Current-voltage relation and reversal potential at junctional and extrajunctional ACh-receptors of the frog neuromuscular junction.
The relationship between synaptic current and membrane potential has been examined at junctional and extrajunctional end-plate receptors of the frog. At junctional receptors, the synaptic current-membrane potential relationship is linear for close range iontophoretic ACh application and non-linear when it is delivered from some distance. At extra-junctional receptors the current-voltage relationship is always non-linear. These non-linearities can be related to the fact that in both cases [ACh] on membrane outlasts the mean life-time of the synaptic channels. When their mean life-time is varied, the current-voltage relationship obtained at junctional receptors is no longer linear and the peak synaptic conductance increases or decreases with hyperpolarization as the channel life time is shortened or lengthened, respectively.
D000109:Acetylcholine / Q000008:administration & dosage / Q000502:physiology*; D000818:Animals; D004553:Electric Conductivity; D007478:Iontophoresis; D009045:Motor Endplate / Q000502:physiology; D009431:Neural Conduction; D009469:Neuromuscular Junction / Q000502:physiology*; D011950:Receptors, Cholinergic; D013570:Synaptic Membranes / Q000502:physiology
D011950:Receptors, Cholinergic; D000109:Acetylcholine