Summary
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1.
Guinea-pig myenteric plexus-longitudinal muscle preparations were superfused at a constant rate and their mechanical activities were monitored.
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2.
Acetylcholine stores were labelled with [3H] choline during 0.1 Hz supramaximal stimulation and the rate of the release of [3H]ACh evoked by the same supramaximal stimulation was followed in the presence of hemicholinium-3 but without cholinesterase inhibition.
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3.
The evoked release of [3H]ACh had an initial fast and a late slow component. Low concentration (1.26 mM) of Ca2+ reduced the rate but not the releasable pool size of [3H]ACh, while 50 nM oxotremorine depressed the evoked release of [3H]ACh. Both low Ca2+ and oxotremorine caused a contraction of the preparation.
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4.
In the presence of 0.5 mM MnCl2 which suppressed contractions, evoked release proceeded at a single rate. The rate of release, but not the size of the releasable pool, was reduced in low Ca2+ and by oxotremorine. The effect of oxotremorine but not that of low Ca2+ was antagonized by atropine.
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5.
Morphine (1 μM) in the presence of MnCl2 reduced the releasable pool size but not the rate of evoked release. Naloxone overcame the effect of morphine.
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6.
The results suggest that low Ca2+ and oxotremorine reduced the amount of ACh released per action potential because of a decreased influx, of Ca2+. In contrast, morphine reduced the evoked release of [3H]ACh by decreasing the number of neurones excited by field-stimulation but did not interfere with the release of ACh directly.
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References
Balustein, M. P.: Effects of potassium, veratridine and scorpion venom on calcium accumulation and transmitter release by nerve terminals. J. Physiol. (Lond.) 247, 617–655 (1975)
Cowie, A. L., Kosterlitz, H. W., Waterfield, A. A.: Factors influencing the release of acetylcholine from the myenteric plexus of the ileum of the guinea-pig and rabbit. Br. J. Pharmacol. 64, 565–580 (1978)
Cox, B. M., Weinstock, M.: The effect of analgesic drugs on the release of acetylcholine from electrically stimulated guinea-pig ileum. Br. J. Pharmacol. 27, 81–92 (1966)
Dingledine D., Goldstein, A.: Effect of synaptic transmission blockade on morphine action in, the guinea-pig myenteric plexus. J. Pharmacol. Exp. Ther. 196, 97–106 (1976)
Down, J. A. Szerb, J. C.: Kinetics of morphine-sensitive [3H]acetylcholine release from the guinea-pig myenteric plexus. Br. J. Pharmacol. 67, (in press, 1979)
Ehrenpreis, S., Sato, T., Takayanagi, I., Comaty, J. E., Takagi, K.: Mechanism of morphine, block of electrical activity in ganglia of Auerbach's plexus. Eur. J. Pharmacol. 40, 303–309 (1976)
Hadházy, P., Szerb, J. C.: The effect of cholinergic drugs on [3H]acetylcholine release from slices of rat hippocampus, striatum and cortex. Brain Res. 123, 311–322 (1977)
Hirst, G. D. S., Holman, M. E., Spence, I.: Two types of neurones in the myenteric plexus of duodenum in the guinea-pig. J. Physiol. (Lond.) 236, 303–326 (1974)
Hubbard J. I.: Mechanism of transmitter release. Prog. Biophys. Mol. Biol. 21, 33–124, (1970)
Johnson, E. S.: The origin of the acetylcholine released spontaneously from the guinea-pig isolated ileum. Br. J. Pharmacol. 21, 555–568 (1963)
Kilbinger, H.: Modulation by oxotremorine and atropine of acetylcholine release evoked by electrical stimulation of the, myenteric plexus of the guinea-pig ileum. Naunyn-Schmiedeberg's Arch. Pharmacol. 300, 145–151 (1977)
Kilbinger, H., Wagner, P.: Inhibition by oxotremorine of acetylcholine resting release from guinea-pig ileum longitudinal muscle strips. Naunyn-Schmiedeberg's Arch. Pharmacol. 287, 47–60 (1975)
Krnjević, K.: Chemical nature of synaptic transmission in vertebrates. Physiol. Rev. 54, 418–540 (1974)
Lees, G. M., Kosterlitz, H. W., Waterfield, A. A.: Characteristics of morphine sensitive release of neurotransmitter substances. In: Agonist and antagonist action of narcotic analgesic drugs (H. W. Kosterlitz, H. O. J. Collier, J. E. Villarreal, eds.), pp. 142–152. Baltimore: University Park Press 1973
Nishi, S., North, R. A.: Intracellular recording from the myenteric plexus of the guinea-pig ileum. J. Physiol. (Lond.) 231, 471–491 (1973)
North, R. A., Henderson, G.: Action of morphine on guinea-pig myenteric plexus and mouse vas deferens, studied by intracellular recording. In: Opiate narcotics, neurochemical mechanisms in analgesia and dependence (A. Goldstein, ed.), pp. 217–220. New York: Pergamon Press 1975
North, R. A., Katayama, Y., Williams, J. T.: On the mechanism and site of action of enkephalin on single myenteric neurons. Brain Res. 165, 67–77 (1979)
North, R. A., Tonini, M.: the mechanism of action of narcotic analgesics in guinea-pig ileum. Br. J. Pharmacol. 61, 541–549 (1977)
North, R. A., Williams, J. T.: Extracellular recording from the guinea-pig myenteric plexus and the action of morphine. Eur. J. Pharmacol. 45, 23–33 (1977)
Opmeer, F. A., Van Ree, J. M.: Competitive antagonism of morphine action in vitro by calcium. Eur. J. Pharmacol. 53, 395–397 (1979)
Rosenberger, L. B., Ticku, M. K., Triggle, D. J.: The effects of Ca2+ antagonists on mechanical responses and Ca2+ movements in guinea-pig ileal longitudinal muscle. Can. J. Physiol. Pharmacol. 57, 333–347 (1979)
Sato, T., Takayanagi, I., Takagi, K.: Pharmacological properties of electrical activities obtained from neurons in Auerbach's plexus. Jap. J. Pharmacol. 23, 665–671 (1973)
Sawynok, J., Jhamandas, K.: Inhibition of acetylcholine release from cholinergic nerves by adenosine, adenine nucleotides and morphine: Antagonism by theophylline. J. Pharmacol. Exp. Ther. 197, 379–390 (1976)
Sawynok, J., Jhamandas, K.: Muscarinc feedback inhibition of acetylcholine release from myenteric plexus in the guinea-pig ileum and its status after chronic exposure to morphine. Can. J. Physiol. Pharmacol. 55, 909–916 (1977)
Sawynok, J., Jhamandas, K.: Interactions of methylxanthines, nonxanthine phosphodiesterase inhibitors and calcium with morphine in the guinea-pig myenteric plexus. Can. J. Physiol. Pharmacol. 57, 853–859 (1979)
Szerb, J. C.: Endogenous acetylcholine release and labelled acetylcholine formation from [3H]choline in the myenteric plexus of the guineappig ileum. Can. J. Physiol. Pharmacol. 53, 566–574 (1975)
Szerb, J. C.: Storage and release of labelled acetylcholine in the myenteric plexus of the guinea-pig ileum. Can. J. Physiol. Pharmacol. 54, 12–22 (1976)
Szerb, J. C., Hadházy, P., Dudar, J. D.: Release of [3H]acetylcholine from rat hippocampal slices: Effect, of septal lesion and of graded concentrations of muscarinic agonists and antagonists. Brain Res. 128, 285–291 (1977)
Vizi, E. S.: Termination of transmitter release by stimulation of sodium-potassium activated ATPase. J. Physiol. (Lond.) 267, 261–280 (1977)
Waterfield, A. A., Kosterlitz, H. W.: Release of acetylcholine from myenteric plexus of the guinea-pig ileum. In: Proceedings of the fourth international symposium on gastro-intestinal Motility (E. E. Daniel, ed.), pp. 659–666. Vancouver: Mitchell Press 1973
Westfall, T. C.: Local regulation of adrenergic neurotransmission. Physiol. Rev. 57, 659–728 (1977)
Wikberg, J.: Release of 3H-acetylcholine from isolated guinea-pig ileum. A radiochemical method for studying the release of cholinergic neurotransmitter in the intestine. Acta Physiol. Scand. 101, 302–317 (1977)
Williams, J. T., North, R. A.: Effects or endorphins on single myenteric neurons. Brain Res. 165, 57–65 (1979)
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Szerb, J.C. Effect of low calcium and of oxotremorine on the kinetics of the evoked release of [3H]acetylcholine from the guinea-pig myenteric plexus; comparison with morphine. Naunyn-Schmiedeberg's Arch. Pharmacol. 311, 119–127 (1980). https://doi.org/10.1007/BF00510250
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DOI: https://doi.org/10.1007/BF00510250