Receptors I
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29 terms
Terms | Definitions |
|---|---|
 cholinergic receptors divided intwo what two categories? | nicotinic and muscarinic |
| Nicotinic Nn receptor | location: postganglioanic neurons and CNS. result of activation: opeining of Na and K channels, depolarization. |
| Nicotinic Nm receptor | location: skeletal muscle (neuromuscular junction) result of activation: opening of Na and K channels, depolarization |
| receptor channels are compoed of how many subunits? | 5 |
| what distingueses Nn from Nm | the differences in the subunit proteins. |
| Receptor channels; each subunit has.. | 4 different channels hat cross the plasma membrane to make the pore. |
| pore of receptor channels lined by? | M2 unit. (formed by M2 segment from each of the protein subunits.) |
| Pore of receptor channels shape? | narrow in middle. selective for size and charge. (negatively charged at openings). |
| In order for receptor channel to open, it requires? | two molecules of Ach to bind on the alpha subunit. (causes equilibrium state betwen open state and closed state.) |
| Neostigmine: cholinesterase inhibitor added to virtual cat | HR: decreases. Why? blocks acetylcholinesterase. Ach present longer. Acts at SA node at M2 receptor. BP: decreases due to HR change muscle: increased contraction (ach there longer) |
| adrenergic receptor: alpha 1 | tissue: vascular smooth muscle effect: constricsts smooth muscle, increases BP |
| adrenergic receptor: alpha 2 | tissue/ex: auto-receptor effect: decreases neurotransmitter release |
| adrenergic receptor: beta 1 | tissue: heart effect: increase HR and heart force |
| adrenergic receptor: beta 2 | tissue: smooth muscle (bronchial) effect: relaxation of smooth muscle |
| adrenergic receptor: beta 3 | tissue: adipose effect:stimulate breakdown of lipids (active in fight or flight) |
| All muscarinic and adrenergic receptors are? | G protein coupled receptors |
| N terminous end of G protein coupled receptor is where? | extracellular |
| where is C terminous end of G protein coupled receptor? | intracellular |
| Approx. how many G protein coupled receptors are there? | over 1,000 |
| G protein coupled receptors are the largest target for? | drugs |
| Inactive G protein | alpha subunit bound to GDP. beta and gamma subunits boud to alpha. entire complex is together. |
| what is roll of G protein coupled receptor? | promote exchange from GTP to GDP |
| Once alpha subunit sees an available GTP, it will? | bind the GTP and kick off a GDP. |
| After alpha subunit binds the GTP what happens? | the beta and gamma stay together and the alpha dissociates from them and alpha subunit has intrinsic GTPase activity |
| what is alpha subunit's intrinsic GTPase activity? | takes off phosphate leaving GDP. The GDP and alpha then associate with the beta and gamma subunits. this turns off the system. cycle begins again. |
| Gi and Gs tend to work against each other, but have? | overlapping effects. Gs-stimulatory Gi-inhibitory |
| Go receptor? | inhibits voltage-gated Ca2+ channels very similar/overlaps with Gi |
| Gq receptor | activates pospholpase C |
| G 12/13 receptor | promotes growth and differentiation |
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