Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
Define types of cellular communication
|
Direct communication-
Connections mediated by released chemical substances- endocrine, paracrine, autocrine |
|
Explain the basis for convergent neurotransmitter (NT) actions.
|
-multiple inputs affect the same effect system
|
|
Explain the basis for divergent neurotransmitter(NT) actions.
|
-one NT activates more than one subtype to elicit more than one type of post-synaptic response
*diff receptors= diff response |
|
Identify and describe the receptor types upon which the different neurotransmitters act.
|
1. Ligand-gated ion channels= ionotropic= Nicotinic
-5 subunits -present at neuromuscular junction 2. G Protein-Coupled Receptors (GPRCs)= metabotropic= Muscarinic -M1-M5 subtypes -differential distribution -differential functions |
|
Identify and describe the Ionotropic receptor subtypes upon which the different neurotransmitters act.
|
Nicotinic:
-NAchRs= pentameric ligand-gated ion channel allows cell to be permeable to Na+ & Ca2+ located at skeletal neuromuscular jxns, autonomic ganglia, adrenal medulla & in CNS Ligand-gated: -nitoctinic Acetylcholine (Na+) -serotonin (Na+, K+) -NMDA, AMPA, & Kainate (glutamate) (Ca2+) -GABA (Cl-) |
|
Identify and describe the Metabotropic receptor subtypes upon which the different neurotransmitters act.
|
GPCR:
-coupled to G proteins -signal transducer |
|
There are both muscarinic/metabotropic & nicotinic/ionotropic cholinergic receptors. Why are they called cholinergic receptors?
|
The are for acetylcholine (ACh)
|
|
What is the consequence of GABA at pentameric ligand-gated channel (NAchRs)?
glutamate? |
depolarization (GABA)
fast depolarization (glutamate) |
|
What are pentameric ligand-gated ion channels blocked by?
|
d-tubocurarine
|
|
(metabotropic/ionotropic) receptors indirectly alter ion conductance & neuron excitability
|
metabotropic
|
|
define autoreceptor & how it decreases NT release
|
-receptors on prejunctional membranes for NE, NPY & ATP feedback (alpha-2)
inhibits AC & NT synthesis |
|
define heteroreceptor & how it decreases NT release
|
-inhibition of sympathetic neurons may also be caused by M2 & M4 muscarinic, serotonin, histamine, & dopamine receptors
inhibits AC & NT synthesis |
|
Describe the signaling mechanism of tyrosine kinase and hormone receptors (nuclear receptors)
|
Phosphorylation within a specific motif on a protein promotes the formation of a scaffolded signaling pathway, and helps to activate and/or localize proteins.
RTKs typically stimulate cell growth and mitosis. |
|
Describe processes for receptor regulation: upregulation
|
-more receptors?
|
|
Describe processes for receptor regulation: downregulation
|
-recycling of receptor back to membrane or degradation of receptor in lysosomal system
|
|
Describe processes for receptor regulation: desensitization
|
-may be a rapid inhibitory effect resulting from phosphorylation or internalization of receptor
-chronic exposure may lead to long-term decrease in responsiveness resulting for receptor down-regulation (degradation) |
|
Describe processes for receptor regulation: denervation supersensitivity
|
-increased response following increased receptor synthesis
-adaptive response resulting from receptor blockade or decreased release of endogenous ligand from pre-synaptic neuron |
|
Describe the role of protein phosphorylation in the regulation of synaptic transmission.
Receptor Sensitivity (e.g., beta-adrenergic receptor desensitization, odorant rec.) |
-can inactivate (desensitize ion receptors)
-alter function of ion channels: open/close more readily & insert into membrane |
|
Describe the role of protein phosphorylation in the regulation of synaptic transmission.
Receptor Trafficking (e.g., AMPA receptor) |
-phosphorylation (by PKa or CaMKII) leads to insertion of AMPA receptor in the membrane
-phosphorylation increases activity HFS---> LTP -dephosphorylation decreases synaptic strength LFS---> LTD |
|
Describe the role of protein phosphorylation in the regulation of synaptic transmission.
Protein Transcription |
-phosphorylation can activate/inactivate enzymes involved in the synthesis of NT
(& in glucose metabolism) |
|
Physiological actions of ionotropic receptors
|
influence synaptic transmission at neuromuscular jxns
|
|
Physiological action of metabotropic receptors
|
-activation of CREB (cAMP response element binding protein) alters gene expression
-leads to changes in neural function |