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 neurons1- voltage gated channels2-synapse types3-neurotransmitters4- receptor types5- 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 NaK 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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atropine, Curare Atropine Receptor, channels Synapses A., channels 2-synapse types