Barbiturate-induced transmitter release at a frog neuromuscular junction.
1. The influence of barbiturates on neuromuscular transmission at end-plates of frog sartorius muscles was investigated electrophysiologically on preparations bathed in Ringer solution containing a low concentration of calcium and a high concentration of magnesium.2. Effects of a convulsant barbiturate, 5-(2-cyclohexylideneëthyl)-5-ethyl barbituric acid (CHEB), were compared with those of phenobarbitone.3. CHEB and phenobarbitone increased the mean quantum content of the end-plate potentials and decreased the mean amplitude of the miniature end-plate potentials.4. Both barbiturates enhanced the duration of the nerve-terminal action potential and had little or no effect on the effective resistance of the skeletal muscle membrane.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001001:Anura; D001463:Barbiturates / Q000494:pharmacology*; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D009132:Muscles / Q000187:drug effects; D009411:Nerve Endings / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects*; D010634:Phenobarbital / Q000494:pharmacology; D011894:Rana pipiens; D009435:Synaptic Transmission; D013997:Time Factors
D001463:Barbiturates; D010634:Phenobarbital