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163 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Which organs have sympathetic predominance?
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Liver
Spleen Adrenal medulla sweat glands most blood vessels |
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Which organs have parasympathetic predominance?
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GI tract
gastric secretion ciliary body |
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Which organs are stimulated by ACh from SNS neurons?
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sweat glands
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True/False. Horse sweat glands are stimulated by NE and ACh.
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True
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True/False. 3,4 dihydroxy substiuents are necessary for maximal sympathomimetic activity.
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True.
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What are 2 mechanisms of indirect sympathomimetic drugs?
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1) displace stored catecholamines
2) inhibit reuptake of released catecholamines |
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How is adrenergic transmission terminated?
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1) diffusion
2) reuptake into nerve terminal 3) transport into postsynaptic cell |
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What is the major termination mechanism of dopaminergic transmission?
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reuptake
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What are the primary effector organs with a1 adrenergic receptors?
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arterioles in skin, mucosa, viscera and kidney
veins uterus |
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What are the primary effector organs with a2 receptors?
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Presynaptic nerve terminals
Postsynaptic nerve terminals in CNS |
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What are the primary effector organs with b1 receptors?
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Heart (increases force and rate of contraction)
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What are the primary effector organs with b2 receptors?
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Arterioles (dilation)
Bronchial and uterine smooth muscle (relaxation) |
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What are the primary effector organs with D1 receptors?
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Arterioles of kidney and mesentery
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For which adrenergic receptor is Epi much more potent than NE?
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Beta-2
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Which adrenergic agonists have greater selectivity for the alpha receptors?
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Phenylephrine
Clonidine |
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Which adrenergic agonists have greater selectivity for the beta receptors?
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Dobutamine
Isoproterenol |
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What is the mechanism of action of the a1 receptor?
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Increase Ca++
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What is the mechanism of action of the a2 receptor?
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Decrease cAMP
Open K+ channel Close Ca++ channel |
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What is the mechanism of action of the beta receptors?
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Increase cAMP
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What is the mechanism of action of the beta1 receptor at the heart?
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Increase cAMP and ultimately increase Ca++
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What is the mechanism of action of the D1 receptor?
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Increase cAMP
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What is the mechanism of action of the D2 receptor?
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Decrease cAMP
Open K+ channel Decrease Ca++ flux |
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Pharmacological effects of catecholamines on blood pressure?
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Increased by a1
Decreased by b2 Indirectly increased by b1 (<a1) |
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Most general anesthetics work through which type of receptor?
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GABA
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True/False. Only volatile anesthetic action is interrupted when mutation are made in the alpha subunit of GABA.
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True.
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How do 2-pore-domain K+ channels inhibit neuronal activity?
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Hyperpolarize the cell membrane
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Where are NMDA receptors located? How do general anesthetics work through them?
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pre, post, and extrasynaptically
blocked by anesthetics |
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Where are glycine receptors located?
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Lower brain stem
Spinal cord |
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True/False. Barbiturates enhance the action of GABA at its receptor, but cannot activate the receptor directly.
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False. Barbiturates can activate the receptor in the absence of GABA.
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True/False. While Etomidate and propofol modulate NMDA receptor, ketamine produces its actions by inhibiting the GABA receptor.
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False. Switch the drugs.
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True/False. Inhalant anesthetics are some of the most high-risk drugs used.
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True.
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True/False. Halogenated alkanes are popular agents because of fewer side effects and best pharmacokinetic profile.
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False. Halogenated ethers.
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How do halogenated anesthetics work?
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Change the physical conformation of the GABAa and glycine receptors, increasing their affinity for their substrates
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How do non-halogenated anesthetics work?
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inhibit excitatory postsynaptic currents by inhibiting NMDA receptors.
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True/False. All halogenated alkane and ether anesthetics can bind to proteins involved in vesicle release and inhibit NT release.
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True
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What are the most important sites of action of the general anesthetics?
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hippocampus
reticular activating system |
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Anesthesia
Stage 1 |
Voluntary movement
Epinephrine release --> tachycardia and hypertension Conscious |
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Anesthesia
Stage 2 |
Excitement and increased CNS stimulation
Beginning of loss of consciousness and voluntary control |
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Anesthesia
Stage 3 |
Plane 1: Palpebral reflexes intact, eye position may change
Plane 2: Palpebral reflexes absent, withdrawal reflex absent, eye position unchanged from Plane 1, muscle relaxation Plane 3: Palpebral reflex absent, eye position forward, abdominal respiration |
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Anesthesia
Stage 4 |
Medullary paralysis.
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Most general anesthetics decrease responsiveness to autonomic reflexes and result in hypotension, decreased heart contractility, bradycardia. Exceptions?
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Nitrous oxide
ketamine |
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True/False. Usually, the hypoxic drive is preserved under general anesthesia.
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True, although there may be decreased responsiveness to CO2
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Explain what a blood:gas partition coefficient of 1.4 means.
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The concentration of the drug in the blood is 1.4 times that in the gas (alveolar) phase at equilibrium. Equilibrium relates to partial pressure.
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What is the relationship between solubility and induction time of inhaled anesthetics?
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The less soluble, the faster partial pressure in the blood increases, the faster rate of rise of anesthesia in the brain.
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Which anesthetic has the fastest onset and termination of action of the volatile anesthetics?
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Sevoflurane
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Which volatile anesthetic agent is used to induce anesthesia and is commonly used in exotic patients?
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Sevoflurane
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Which volatile anesthetic is popular in lab animal medicine?
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Methoxyflurane
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True/False. Nitrous oxide can be used to maintain anesthesia alone.
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False. However, it can be used to decrease the required dose of another agent.
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Administration of which drug will inhibit liver metabolism of barbiturates and prolong duration of recovery?
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Chloramphenicol
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Which injectable GA is used with patients with brain disease?
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Thiopental because it decreases cerebral metabolism and oxygen consumption.
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Which injectable GA is used in sighthounds and why?
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Methohexital. Redistribution and metabolism of thiopental is relatively slower in these breeds.
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What is the mechanism of action of propofol?
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acts at GABAa receptors to cause hyperpolarization of postsynaptic cell membranes
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Chemical classes of drugs that constitute neuroleptics
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Phenothiazine
Butyrophenone Rauwolfia Alkaloid |
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Chemical classes of drugs that constitute anxiolytics
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Benzodiazepine
Non-Benziodiasepine (Buspirone) |
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Chemical classes of drugs that constitute sedatives-hypnotics.
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Barbiturates
Benzodiazepines Chloral Hydrate Alpha 2 Adrenergic Agonists |
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Use and MOA of phenothiazine
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antagonist to D2, alpha, muscarinic and H2 receptors
Antipsychotic, behavior modification, anti-emetic, hypotensive, anti-pruritic |
Hypothalamic in nature:
Impair temperature regulation Increased ADH release Decrease GnRH, GH, ACTH, PIF increased appetite hypotension and tachycardia |
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Use and MOA of xylazine
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alpha 2 agonist
sedation by suppressing ARAS pain suppression by inhibiting NA inhibition of 5-HT |
Contraindicated with heart disease (interference with cardiac conductivity)
Bradycardia Emesis Diarrhea Tympany |
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Use and MOA of benzodiazepine
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anxiolytic, anticonvulsant, muscle relaxant
Potentiate neural inhibition by GABA |
drowsiness, ataxia
potentiate other CNS depressants (alcohol) hepatotoxicity in cats |
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Use and MOA of barbiturates
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anesthetic induction, anticonvulsant
Potentiate neural inhibition by GABA. |
Cardiovascular and respiratory depression
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Reveral agent for benzodiazepines?
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Flumazenil
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Reversal agents for xylazine?
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Alpha 2 antagonists
Yohimbine atipamezole tolazoline |
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Why use a2 agonists with caution in sheep?
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Causes dyspnea w/ cyanosis
pulmonary edema |
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Why inject benzodiazepines slowly?
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Formulated in propylene glycol
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What is the prototypical phenothiazine?
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Chlorpomazine/acepromazine
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What is the prototypical a2 agonist?
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Xylazine
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What effect do the phenothiazines with high noradrenergic affinity have (relative to those with high dopaminergic affinity)?
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Sedative
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What effect is seen by specific phenothiazines and why?
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Antipsychotics as they have high affinity for dopaminergic neurons.
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Which sedative is also used to relax the penis in bulls for examination?
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Phenothiazines
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True/False. Phenothiazines are often used as a pre-anesthetic and provide analgesia.
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False. Used in pre-anesthetic but have little to no analgesic activity
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True/False. Butyrophenones share many of the same properties as Phenothiazines.
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True.
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Other than tranquilization, what are other effects of butyrophenone?
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anti-emetic
anti-psychotic relaxation (spasticity at high doses) tachycardia |
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What receptor effects are seen with the new antipsychotics?
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Antagonism of both 5-HT2 and D2 receptors
Fewer extrapyramidal side effects |
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Which sedative can cause retrograde amnesia?
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Benzodiazepines
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Which sedative can cause hepatotoxicity in cats?
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Benzodiazepines
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Which sedative is metabolized by the liver to active metabolites with long effects?
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Benzodiazepines
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Which anxiolytic is used to treat spraying in cats and lacks anticonvulsant and muscle relaxant activity?
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Buspirone
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Which sedative is used on large animals in the field (international vet med)?
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Chloral hydrate
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Which sedative is much more potent in ruminants than other animals?
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Xylazine
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True/False. Xylazine is typically administered orally.
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False, not absorbed well. Administered IM
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True/False. Sedative doses of a2 agonists typically raise the blood pressure.
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True.
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Which sedative causes profuse salivation, in addition to loss of tone in large intestine?
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Xylazine
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Which sedative causes partial penile paralysis?
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Xylazine
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True/False. Xylazine-ketamine combinations may be responsible for anesthetic deaths.
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True.
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True/False. All local anesthetics are weak bases.
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True. Administered as HCl salt
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True/False. Local anesthetics work by blocking Ca++ channels and therefore neurotransmission.
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False. Block voltage-gated Na channels
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True/False. Local anesthetics bind to the receptor near the extracellular end of the Na++ channel.
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False. Intracellular.
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True/False. The effect of a given concentration of local anesthetic is more marked in rapidly firing axons than resting fibers.
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True.
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For myelinated nerves, how many successive nodes must be blocked to halt impulse propagation?
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3
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What effect does elevated serum calcium have on local anesthetics?
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Partial antagonism
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What effect does elevated potassium have on local anesthetics?
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Increases effects by depolarizing the membrane and favoring an inactivated state.
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Severe liver disease and reduced liver blood flow may lead to significant increase in concentration of which type of local anesthetic?
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Amide local anesthetic
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Prilocaine or benzocaine may produce what in cats and rabbits?
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methemoglobinuria
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Whcih species is most susceptible to cardiovascular toxicity of lidocaine?
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Cats
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Sulfonamides should not be used with what local anesthetics?
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PABA containing, such as procaine. Will interfere with inhibition of folate synthesis.
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What effects make local anesthetics useful as antiarrhythmics?
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Block fast Na+ channel in cardiac cell membrane
decrease HR Increase AP duration Lengthen refractory period |
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True/False. The Nm receptor is a ligand-gated Na+ channel.
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True.
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Which ANS receptors act by formation of IP3 and DAG and increasing intracellular Ca++
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M1, M3, alpha 1
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Which ANS receptors act by stimulating AC and increasing cAMP?
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beta receptors
D1 |
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Which ANS receptors act by inhibiting AC?
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M2, M4 (in addition to opening K+ channels)
alpha 2 |
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Hemicholinum
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Inhibit choline reuptake
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ACh receptor antagonists
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Curare (NM junction)
Atropine (Muscarinics) Hexamethonium (ganglionic) Succinylcholine (NM junction) |
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scribo, scribis, scribit, scribunt
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write, writes, are writing
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CNS effects of the opioids?
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Analgesia
Sedation Cough suppression Nausea and Vomiting Respiratory depression Thermoregulatory changes |
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True/False. Opioids are inhibitory to deep pain, pressure and touch.
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False. Analgesia against dull aching pain
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What is the mechanism of analgesia of opioids in the spinal cord?
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Inhibit NT release by closing Ca++ channels
Inhibit pain transmission neurons directly Inhibitory to interneurons and thus antagonizes action of substance P |
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What is the mechanism of analgesia of opioids in the supraspinal structures?
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Inhibition of output neurons of the spinothalamic tract to higher centers of the brain.
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Why administer opioids epidurally?
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Minimizes unwanted respiratory depression, nausea and vomiting
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Which animals are excited by opioids?
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horses
pigs cows sheep cats |
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Which animals are sedated by opioids?
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primates
dogs |
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If respiratory depression following an opioid administration, what can be given to reverse the effects?
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Naxolone
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Why should opiates be avoided in dogs with comprimised respiratory function?
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Causes bronchoconstriction in dogs
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Which opioids are used as antitussives?
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codein
dextromethorphan butorphanol |
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Which species show increased body temp in response to opioids?
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cats
goats cattle horses |
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Which species show decreased body temp in response to opioids?
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dogs
rabbits monkeys |
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Which opioids are used as antidiarrhetics?
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loperamide
diphenoxylate |
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Which species show mydriasis in response to opioids?
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cats
horses sheep |
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How can tolerance to opioids be minimized?
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give small amounts of drug less fequently
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Which features of opioids are unaffected by development of tolerance?
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Gi motility
convulsions eye |
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What opioid structural modification incrases narcosis and respiratory depression?
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Alcoholic hydroxyl substitutions
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What is the primary use of etorphine?
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immobilization of wild animals?
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What drug is recommended for reversal of etorphine effects?
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diprenorphine
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For what conditions are opioids contraindicated?
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hypothyroidism
renal insufficiency adrenocortical insufficiency head trauma/seizures compromised respiratory function |
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Name 2 opioid mixed agonist/antagonists
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buprenorphine (agonist at mu, antagonist at kappa)
Butorphanol |
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What other opioids are reversed by butorphanol?
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morphine
oxymorphone |
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True/False. Naloxone has been shown to be beneficial in treatment of septic, hypovolemic and cardiogenic shock.
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True
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True/False. Certain toxins can cause seizures by increasing the availability of excitatory neurotransmitters in the brain.
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True.
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What are the 2 mechanisms of action of common anticonvulsants?
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Enhancement of GABAergic transmission
Inhibition of excitatory (glutaminergic) transmission |
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True/False. Hyperpolarization decreases the seizure threshold.
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False.
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MOA of phenobarbital.
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Potentiates GABAergic inhibition
Opens Cl- channels |
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Side effects of phenobarbital
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sedation
ataxia polyphagia PU/PD hyperexcitability (rare) |
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Doses of which other drugs need to be increased if given with phenobarbital?
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digitoxin
glucocorticoids doxycycline estrogens |
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Which drugs increase the CNS depressive response of phenobarbital?
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sulfonamides
salicylates |
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True/False. Primidone is metabolized to phenobarbital and PEME, and all three are active anticonvulsants.
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True.
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True/False. Primidone is more toxic in dogs than cats.
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False. The opposite
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What is the drug of choice to treat status epilepticus in dogs and cats?
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Diazepam
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Why should diazepam be administered slowly?
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The propylene glycol can cause cardiac arrhythmias
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MOA of potassium bromide?
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synergistic inhibition with drugs that open the Cl- channel via GABA receptor activation
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MOA of phenytoin?
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Inhibits Na+ channels on axon hillock of excitatory neurons.
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What is the drug of choice for digitalis-induced ventricular arrhythmias?
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Phenytoin because of its lidocaine-like effects
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Which broad classes of drugs may induce seizures?
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Phenothiazines
Local anesthetics |
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Which drug may increase toxicity of anticonvulsants by decreasing their metabolism?
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Chloramphenicol
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Name 2 muscarinic agonists that are:
a) direct acting b) indirect acting |
a) bethanechol
b) physostigmine |
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What is the mechanism of indirect acting cholinergic drugs?
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Inhcrease the concentration of ACh
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True/False. Like ACh, indirect cholinergics undergo a 2 step hydrolysis sequence by ACh esterase.
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True.
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True/False. Phenothiazines have similar structure to atropine and thus have significant antimuscarinic effects.
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True.
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In what conditions should ACh esterase inhibitors be given with caution?
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Liver disease (pseudocholinesterase produced by liver)
Respiratory disease (bronchoconstriction) Late pregnancy (abortion) |
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Antimuscarinic drugs should be used with caution in patients with:
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gastric ulcer
glaucoma |
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True/False. Herbivores are more resistant to atropine.
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True.
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What is a nondepolarizing neuromuscular blocker?
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d-tubocurarine
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What is a depolarizing neuromuscular blocker?
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succinylcholine
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Which type of neuromuscular blocker is enhanced by ACh esterase inhibitors?
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Depolarizing
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True/False. All the neuromuscular blocking drugs bear a structural resemblance to atropine.
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False. To ACh
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True/False. Neuromuscular blocking drugs have poor lipid solubility and are always administered IV.
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True.
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True/False. Muscles capable of rapid movement, such as those of the jaw and eye are paralyzed before larger muscles of the limb and trunk.
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True.
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Which sedatives are also used as muscle relaxants?
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Diazepam
Xylazine |
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What are the effects of M3 activation?
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increased secretion of exocrine glands
relaxation of sphincters bronchoconstriction |
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Atropine is mostly excreted unchanged in the urine, except in which species?
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Rabbits havae a specific enzyme that metabolizes it.
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Why should one be careful using AChE inhibitors with phenothiazines?
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They also inhibit AChE
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What are the 2 indirect mechanisms for adrenergic drugs?
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1) displacement of stored catecholamines
2) inhibition of reuptake of atecholamines already released |
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Isoprotenerol is most ptoent at which receptor(s)?
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b1 and b2
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True/False. NE preferentially activates b1 receptors compared to b2 receptors.
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True.
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True/False. Isoprotenerol preferentially activates alpha receptors relative to beta.
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False. The opposite is true.
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True/False. All adrenergic agonists are catecholamines and can be metabolized by COMT.
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False.
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