HSC 350 Chapter Notes - Chapter 6: Lateral Geniculate Nucleus, Optic Tract, Ganglion Cell
Document Summary
In the dark, lots of sodium comes in through cgmp binding to the channel. When light comes in, it changes conformation of rhodopsin, activates g-protein and also activates phosphodiesterases. It cleaves the cgmp, so there is no cgmp to open the channel so the channel is closed. Shining light on a photoreceptor (rod or cone) leads to membrane. The resting potential of photoreceptors is about -30mv, however it can hyperpolarize to -60 mv in the light. Some ganglion cells also have phtoreceptors called melanopsin. Note that the amacrine, bipolar, and horizontal cells don"t have action potentials. Interactions with horizontal and amacrine cells that release the inhibitory neurotransmitter. Gaba influence signaling laterally (make the visual process more complex) Two classes of bipolar cells: on bipolar cells. G-protein-coupled receptors (mglur6) hyperpolarize to glutamate released by photoreceptors (cascade closes cgmp-gated na channels) depolarize when there is light: off bipolar cells.
