title: The effects of hemicholinium-3 (Hc-3) during tetanic (TP) and posttetanic potentiation (PTP) on sympathetic ganglion.
abstract: An electrophysiological analysis has been made of the synaptic plasticity in the eighth sympathetic ganglion of the toad. The mean amplitude of Compound Action Potential (CAP) recorded extracellularly was taken as a measure of the synaptic transmission. Repetitive stimulation of the preganglionic axonal fibers at 50 Hz for 40 seconds in the presence of Hc-3 led to facilitatory and depressant actions on ganglionic synaptic transmission. Hc-3 in the presence of elevated extracellular Ca2+ concentration (5.4 mM) increased Tetanic Potentiation (TP) and Posttetanic Potentiation (PTP) on eighth sympathetic ganglion. Hc-3 plus 3,4-diaminopyridine (3,4-DAP) increased synaptic transmission, TP, and PTP from postganglionic CAP responses to supramaximal preganglionic stimulation.
mesh_terms: D015761:4-Aminopyridine / Q000031:analogs & derivatives*; D000200:Action Potentials / Q000187:drug effects; D000077770:Amifampridine; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D001001:Anura; D002118:Calcium / Q000494:pharmacology; D004558:Electric Stimulation; D004594:Electrophysiology; D005728:Ganglia, Sympathetic / Q000187:drug effects* / Q000502:physiology; D006426:Hemicholinium 3 / Q000494:pharmacology*; D009119:Muscle Contraction; D013569:Synapses / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D000631:Aminopyridines; D006426:Hemicholinium 3; D015761:4-Aminopyridine; D000077770:Amifampridine; D002118:Calcium