lecture 32 lecture - Lecture 32: Synapses -action...

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Lecture 32: Synapses -action potential: propagation -myelinated neurons: sltatory conduction -current jumps from 1 node to the next. The velocity can reach 150 m/s -voltage gated channels in myelinatex axons are found only at the Nodes of Ranvier -teased sciatic nerve to reveal individual neurons 1- voltage gated channels 2-synapse types 3-neurotransmitters 4- receptor types 5- synaptic integration -the ionic basis of action potential was worked out in the giant axon of the squix -How do we know about channels? Toxins! Na channels: TTX blocks Na K channels: TEA blocks K -voltage gated potassium channel: active channel is composed of 4 subunits that can vary depending upon the tissue -variation provides different dynamics and binding properties -voltage gated sodium channel: very large protein, no structure yet but 4 repeat domains, each with 6 TM domains -s4 region acts as voltage sensor -region between s5 and s6 is selectively filter -patch recordings confirm channel existence
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This note was uploaded on 03/03/2010 for the course BIOG 1101 taught by Professor N/a during the Fall '10 term at Cornell University (Engineering School).

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