Postsynaptic potential and postsynaptic current in muscle fibres with large time-constant. EPSP amplitude is independent of membrane resistance.
1. Equations have been developed for a computer programmed calculation of synaptic current from synaptic potentials (epsps). 2. The method permits separation of presynaptic and postsynaptic effects in experiments involving drugs which affect synaptic transmission. It is particularly applicable where the postsynaptic cells are large as in the case of commonly employed crustacean muscle fibres. 3. Contrary to a widely held view the theoretical approach used predicts that epsp-amplitude is relatively independent of membrane resistance. 4. Confirmation is provided by experiments involving the application of barium which increases, and of GABA which decreases membrane resistance.
D000818:Animals; D003400:Astacoidea; D001464:Barium / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008954:Models, Biological; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D009431:Neural Conduction / Q000187:drug effects; D013569:Synapses / Q000187:drug effects*; D013570:Synaptic Membranes / Q000502:physiology; D013997:Time Factors
D001464:Barium