Final Review Session, 3/19/2012
(hippocampal)Slight elevation of calcium favors phosphatases and clips of phosphates on ampa receptors so that fewer receptors are in the postsynaptic membrane and some are dephosphoylated. (reversing LTP).
NO NMDA? receptors involved in cerebellar, metabotropic receptors in cerebellum kick off PIP2 pathway, get PKC activation and causes internalization of AMPA receptors. Parallel and climbing fiber activity must correlate.
Climbing fibers and parallel fibers are associative LTD in the cerebellum and can also be heterosynaptic, certainly not homosynaptic.
Alpha causes muscles to contract, gamma motorneurons. Stretch receptors sense contractile state of the muscle and the stretch receptors get unloaded and there is no more tension on the stretch receptor and the gamma motor neurons retract so that there is tension on the alpha motor neurons and bring back tension.
Photoadaption has to do with drop in calcium channels, calcium is at high levels in steady state sitiation in the dark current and when light goes down, channels close and lights drop. Rhodopsin kinase, phosphylates rdohopsin. Calcium drops, inhibitions are released, channels open and become available for light response in the next available range.disinhibitions releases the strain off of GC which produces more cGMP and binds to the cGMP receptor more, less cGMP is chewed up by PDE and the metarhodopsinII shutsoff. You want to shut off the light response… activated rhodopsin causes activated phosphodisesterase to chew up the ligand. The last 15 AA from c-terminus of rhodopsin it cannot be phosphylated anymore and stays active.
There is also adaptation in the primary olfactory cells, calcium comes in binds to CaM. Channels are normally closed and these ORC depolarize, cAMP is produced and opens channels, calcium comes in and amplifyings the effect by gating