1. Local endplate depolarization induced by anticholinesterase application to mouse nerve-diaphragm preparations was taken as a measure of non-quantal release of acetylcholine. 2. Non-quantal acetylcholine release occurred within 20-60 s after anticholinesterase application, either spontaneously or evoked by nerve stimulation. Non-quantal release declined with time and disappeared after 3-5 min. 3. The amplitude of stimulation-evoked non-quantal release increased with the frequency of stimulation and was maximal at frequencies above 50 Hz. Two stimuli were sufficient to evoke the maximal effect. 4. Micromolar concentrations of atropine, pirenzepine and vesamicol reduced the amplitude and shortened the duration of non-quantal release. Oxotremorine (10(-8) M) enhanced the amplitude and ouabain (10(-4) M) prolonged the duration of non-quantal release. 5. Our results support the idea that the non-quantal release is due to the vesicular acetylcholine transport system which becomes transiently a part of the nerve terminal during exocytotic release of quantal acetylcholine.

Institute of Physiology Czechoslovak Academy of Sciences Department of Cellular Neurophysiology Praha

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Neurosci Lett. 1985 Sep 6;59(3):277-80 PubMed

J Physiol. 1957 Oct 30;138(3):434-44 PubMed

Pflugers Arch. 1987 Aug;409(4-5):540-6 PubMed

J Physiol. 1954 Jun 28;124(3):586-604 PubMed

Nature. 1980 Jan 3;283(5742):90-2 PubMed

Pflugers Arch. 1983 Jun 1;397(4):319-22 PubMed

Proc R Soc Lond B Biol Sci. 1981 May 7;212(1186):131-7 PubMed

J Physiol. 1986 Mar;372:395-404 PubMed

J Physiol. 1979 Jan;286:1-14 PubMed

Physiol Bohemoslov. 1978;27(5):449-55 PubMed

Proc R Soc Lond B Biol Sci. 1977 Feb 11;196(1122):59-72 PubMed

J Physiol. 1987 Apr;385:147-67 PubMed

P R Health Sci J. 1988 Aug;7(2):71-4 PubMed

Proc Natl Acad Sci U S A. 1985 May;82(10):3514-8 PubMed

Neurosci Lett. 1989 Sep 11;103(3):293-7 PubMed

J Physiol. 1956 Jun 28;132(3):650-66 PubMed

Mol Pharmacol. 1983 Jul;24(1):48-54 PubMed

Nature. 1984 Feb 2-8;307(5950):457-60 PubMed

Pflugers Arch. 1977 Sep 16;370(3):295-7 PubMed

J Cell Biol. 1985 Nov;101(5 Pt 1):1953-65 PubMed

J Physiol. 1950 Oct 16;111(3-4):408-22 PubMed

J Gen Physiol. 1981 May;77(5):503-29 PubMed

Neuroscience. 1983 Jun;9(2):429-35 PubMed

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