Week%204%20-%20Teacher%20Edition

Week%204%20-%20Teacher%20Edition - B IPN 100 Dr. Fortes...

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BIPN 100 Chris Childers Dr. Fortes Winter 09 Lecture 7 – January 21 st Lecture 8 – January 23 rd Lecture 9 - January 26 th Lecture 10 - January 28 th Ionotropic vs. metabotropic Ach receptors – nicotinic Currare, Cobra Venom, Myasthenia Gravis Neurotransmitters & their derivatives Neurotransmitters cont. Spatial and temporal summation Convergence and divergence Long term potentiation Spinal chord anatomy Spinal Reflexes Neuroanatomy – Brain Stem Diencephalon Telencephalon Cerebral Cortex Phinease Gage Lateralization Language association areas Order the following events for synaptic transmission in the correct order…. A. Voltage gated Ca2+ channels are opened and Ca2+ enters the cell B. Ach reacts with acetylcholinesterase C. Depolarization of axon hillock of pre synaptic cell D. Ach diffuses across the synaptic cleft and binds to a post-synaptic receptor E. Depolarization of post synaptic cell F. Exocytosis of synaptic vesicles G. Depolarization of axon terminal H. Action potential is conducted down the axon C H G A F D E B There are two broad categories of post synaptic receptor, ionotropic and metabotropic. Whereas ionotropic receptors are opened directly by binding of a ligand, metabotropic receptors require signaling cascades. Describe the basic mechanism of G-protein coupled signal transduction. 1. Ionotropic The reeptor itself is a ligand-gated channel – when the NT binds, the channel will open (possibly leading to a depolarization or a hyperpolarization depending on the ion). These are quick responses. 2. Metabotropic The receptors are not channels themselves. Instead, binding of the NT to the receptor causes signal transduction through a variety of pathways. One of the largest family – G Protein coupled receptor. In the absence of a stimulation by a hormone or NT, the G proteins are in the “inactive” position (alpha subunit has GDP bound). Binding of the hormone causes a conformational change in the receptor (seven transmembrane segments) activating the alpha subunit (by changing out GDP with GTP). The dissociated beta and gamma subunits have additional effects on ion channels. In turn, G proteins (specifically the enzymatic activity of the alpha subunit) can turn on additional enzymes which will synthesize second messengers (cAMP, Ca2+, DAG, IP3) which will activate protein kinases (enzymes that phosphorylate proteins, specifically serine and threonine amino acids). Eventually GTP will be hydrolyzed back to GDP which “turns off” the switch.
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BIPN 100 Chris Childers Dr. Fortes Winter 09 What are the two types of acetylcholine receptors? Where are they primarily found? What channels do they open? Are they excitatory? Inhibitory? Both? Ionotropic? Metabotropic? 1.
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Week%204%20-%20Teacher%20Edition - B IPN 100 Dr. Fortes...

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