PSL300H1 Lecture Notes - Lecture 16: Adenylyl Cyclase, Axon Hillock, Ligand-Gated Ion Channel
Document Summary
Ionotropic opens ion channels: metabotropic initiates metabolistic cascade, doesn"t necessarily change. Mp: receptor, not transmitter, epsp excitatory, depolarizing, na+/k+ channel targets. Ipsp inhibitory, hyperpolarizing, cl- /k+ channel targets: as long as ligand is bound to receptor, acetylcholine -> binding results in cation influx -> depolarization -> epsp, happens very fast, hyperpolarization. Ipsp: yes, na binding -> adenylyl cyclase activation -> camp production -> phosphorylation of ca+ channel -> ca+ influx -> heart contraction, decrease ca+ influx and decrease heart contractions. Epsp at higher frequency: temporal involves successive inputs before previous epsp dies out, spatial involves all at the same time, cell body between synapse and trigger zone. Location allow shunting of depolarizing currents through cl- influx: very near -70mv, channels can open when membrane is depolarized to shunt epsp. Ipsp: depolarization sustained at trigger zone for more than 500ms -> continuous streams of aps, hyperpolarization to overcome refractory period.
