PHGY 314 Lecture 39: PHGY314 Sharif 4 Pathology of NeP
8 Dec 2016
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Outline of all 4 lectures: peripheral sensory transduction, dev of subset of sensory neurons, dorsal horn of spinal cord"s interneurons/info processing, pathology of neuropathic pain (nep) Primary a-beta fibre sends quick aps to synapse, avg 40hz, to excitatory chain and collateral inhibitory interneurons. Pv neurons receive info from primary touch afferents at 40hz, need to slow down firing in excitatory chain. This is a mechanism for less inhibition = spike frequency adaptation: slows down the firing rate. Influx of ca++ into neurons via vgcc when a-beta inputs to pv neuron: activate ca-gated k+ channel (sk) conductance, big conductance) Sk/ik/bk. (small conductance k+ channel gated by ca++, intermediate. Pv neurons get sk channels that cause repolarization when depolarized, this is homeostatic: so no repolarization. Pv chelates the calcium to prevent it from activating k+ channels, so typically the pv neuron will fire constantly.
