Summary
The influence of adenosine upon the process of transmitter release was investigated in Mg2+-paralyzed frog neuromuscular junction by using conventional microelectrophysiological techniques and binomial statistical analysis. The statistical parameters used were: m (mean number of quanta released per impulse), p (the probability of quantal release) and n (store of quanta available for release). Adenosine decreased the mean quantal content m by reducing n. This effect appeared to be dependent upon the free intracellular Ca2+. The nucleoside competed with the transmitter releasing effects of ouabain and increased the amount of effective Ca2+ necessary for quantal release. It did not change the slope of release parameters modification during low-frequency facilitation. The data are discussed in terms of a physical model of release.
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The authors would like to thank Dr. R. L. Volle, Dr. E. Henderson and Dr. A. Pappano from the UConn. Health Center Farmington Dept. of Pharmacology, for helpfull advice in doing this work.
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Brani§teanu, D.D., Haulică, I.D., Proca, B. et al. Adenosine effects upon transmitter release parameters in the Mg2+-paralyzed neuro-muscular junction of frog. Naunyn-Schmiedeberg's Arch. Pharmacol. 308, 273–279 (1979). https://doi.org/10.1007/BF00501393
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DOI: https://doi.org/10.1007/BF00501393