BISC306 Lecture Notes - Lecture 7: Inhibitory Postsynaptic Potential, Neuromuscular Junction, Reversal Potential
20 Feb 2017
School
Department
Course
Professor
Document Summary
At the reversal potential, erev=vm: -ik=ina, -gk(vm-ek)=gna(vm-ena, vm=erev= (gk*ek)/(gk+gna)+(gna*ena)/(gk+gna) Problem: these are recordings from a neuron in snails called an h type cell. Stimulation by ach under physiological conditions (a) will open up chloride channels which hyperpolarize these cells. In this case ach is an inhibitory nt. But under experimental conditions ach can become an excitatory transmitter (b). Explain: difference in the receptor, cells are bathed in saline ringers (physiological, [cl-]in = 6 mm, [cl-]out = 110 mm, cells are bathed in so4. Ringers: [cl-]in = 6 mm, [cl-]out = 25 mm, what is the approximate threshold potential for ap production, what would erev be in saline ringers, what would erev be in so4. Synaptic transmission at vertebrate motor endplates are always excitatory: the post synaptic membrane depolarizes, called an excitatory postsynaptic potential or epsp, increases probability of ap, spiking cells send excitatory.
