NPB 100 Lecture Notes - Lecture 11: Dorsal Root Ganglion, Mechanotransduction, Axon Hillock
13 Feb 2018
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Mechanotransduction (cid:498)stretch-activated(cid:499) mechano sensitive ion channels: called (cid:498)receptor (cid:523)or (cid:498)generator(cid:499)(cid:524) potential(cid:499) depolarize nerve ending, receptor potential is graded,, transmitted to site of voltage-gated na+ and k+ channels (at first myelin sheath in myelinated axons) If receptor potential exceeds threshold, it will generate action potential. Unipolar somatosensory neurons: axon hillock not at the soma in unipolar neurons, some is in the dorsal root ganglion, can have receptor rather than true dendrites, action potential initiated distally, goes right past soma. Mechanisms of mechanotransduction: stretch-activated ion channels open when forces in the lipid bilayer change, tethered: some mechanically gated channels require links to extracellular or cytoskeletal proteins. Displacements that change tension on these links open the channel. The links may directly transmit force to the channel protein or alter membrane forces around stretch-sensitive channels: indirect gated: mechanosensitive protein regulates ion- channel opening through an intracellular second messenger.
