Biphasic Effect of Calcium on Tetanic Potentiation at the Frog Neuromuscular Junction

摘要: High frequency stimulation of the motor nerve produces an increase in transmitter release, termed tetanic potentation. Previous work showed that calcium ions extracellular medium are important factor generating potentiation (Rosenthal, 1969; Weinreich, 1971. Using spontaneous mepps as indicator it was suggested accumulation inside terminal is largely responsible for this phenomenon (Erulkar, Rahamimoff & Rotshenker 1978; Erulkar Rahamimoff, Lev-Tov 1980; Meiri, 1980). The intracellular presumably caused by entering via surface membrane and released from stores. Regardless its origin, expected such elevated may produce a change relationship between release calcium.