Post-tetanic potentiation in ganglia which are blocked with hexamethonium.
1 Post-tetanic potentiation (p.t.p.) of the compound action potential in the presence of hexamethonium was observed in the isolated stellate ganglion of the hamster using extracellular postganglionic recordings. 2 The magnitude of the p.t.p. was small (less than a 20% increase) in the control solution, but increased as the depth of blockade with hexamethonium was increased. 3 The magnitude of the p.t.p. was frequency-dependent between 1 and 40 Hz. 4 Atropine partially blocked the p.t.p. 5 McN-A-343, a muscarinic agonist, potentiated ganglionic transmission which had been partially blocked by hexamethonium. 6 Repetitive stimulation in the presence of hexamethonium potentiated the discharges induced by DMPP, a nicotonic agonist. The potentiation was blocked by atropine. 7 It was concluded that the p.t.p. in the presence of hexamethonium has the same characteristics as p.t.p. in the control solution. There appears to be both a muscarinic component and a presynaptic component of the p.t.p.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D006224:Cricetinae; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006584:Hexamethonium Compounds / Q000494:pharmacology*; D066298:In Vitro Techniques; D010277:Parasympathomimetics / Q000494:pharmacology; D013233:Stellate Ganglion / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D013997:Time Factors
D006584:Hexamethonium Compounds; D010277:Parasympathomimetics; D004246:Dimethylphenylpiperazinium Iodide; D001285:Atropine