Summary
The purpose of the present study was to further characterize the α-adrenoceptors located on parasympathetic fibres. Segments of guinea-pig ileum were stimulated by transmural electrical pulses, and the ensuing contractions, which are due to the release of acetylcholine from postganglionic parasympathetic fibres, were monitored. Clonidine and tramazoline, which are thought to act preferentially on presynaptic α-adrenoceptors, reduced the contractions, whereas phenylephrine and methoxamine, postsynaptic α-adrenoceptor agonists, were ineffective. Contractions induced by acetylcholine were not changed by clonidine but were abolished by atropine. Yohimbine, piperoxan, phentolamine and thymoxamine reversed or prevented the inhibitory effect of clonidine. Prazosin and AR-C239 did not antagonize this effect. The inhibitory effect of tramazoline was antagonized by piperoxan but not by AR-C239 or by prazosin. Naloxone did not alter the action of clonidine, and piperoxan did not change the inhibitory effect of morphine.
In conclusion, these experiments suggest the presence on cholinergic postganglionic fibres of both opiate receptors and α-adrenoceptors. The latter appear to resemble more closely α1-adrenoceptors than α1-adrenoceptors.
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References
Benfey, B. G., Grillo, S. A.: Antagonism of acetylcholine by adrenaline antagonists. Br. J. Pharmacol. 20, 528–533 (1963)
Cambridge, D., Davey, M. J., Massingham, R.: Prazosin, a selective antagonist of post-synaptic α-adrenoceptors. Br. J. Pharmacol. 59, 514–515 P (1977)
Deck, R., Oberdorf, A., Kroneberg, G.: Die Wirkung von 2 (2,6-Dichlorophenylamino)2-imidazolin Hydrochlorid (Clonidin) auf die Kontraktion und die Acetylcholin-Freisetzung am isolierten, koaxial elektrisch gereizten Meerschweinchenileum. Arzneim. Forsch. 21, 1580–1584 (1971)
Drew, G. M.: Effects of α-adrenoceptor agonists and antagonists on pre- and postsynaptically located α-adrenoceptors. Eur. J. Pharmacol. 36, 313–320 (1976)
Drew, G. M.: Pharmacological characterization of the presynaptic α-adrenoceptors regulating cholinergic activity in the guinea-pig ileum. Br. J. Pharmacol. 64, 293–306 (1978)
Fiedling, S., Wilker, J., Hynes, M., Szewczak, K., Novick, W. J., Lal, H.: A comparison of clonidine with morphine for antinociceptive and antiwithdrawal actions. J. Pharmacol. Exp. Ther. 207, 899–905 (1978)
Gillespie, J. S., Khoyi, M. A.: The site and receptors responsible for the inhibition by sympathetic nerve of intestinal smooth muscle and its parasympathetic motor nerve. J. Physiol. (Lond.) 267, 767–789 (1977)
Gold, M. S., Redmond, D. E., Kliber, H. D.: Clonidine in opiate withdrawal. Lancet 1978, 929–930
Kilbinger, H., Wessler, I.: Increase by α-adrenolytic drugs of acetylcholine release evoked by field stimulation of the guinea-pig ileum. Naunyn-Schmiedeberg's Arch Pharmacol. 309, 255–257 (1979)
Kosterlitz, H. W., Watt, A. J.: Kinetic parameters of narcotic agonists and antagonists, with particular reference to-N-allylnoroxymorphone (naloxone). Br. J. Pharmacol. 33, 266–276 (1968)
Langer, S. Z.: Presynaptic regulation on catecholamines release. Biochem. Pharmacol. 23, 1793–1800 (1974)
Mouillé, P., Huchet, A. M., Lucet, B., Chelly, J., Schmitt, H.: Interactions between clonidine and some α-adrenoceptor blocking drugs on the tachycardic response to stimulation of the cardiac nerve in dogs. J. Cardiovas. Pharmacol. 1, 515–528 (1979)
Oberdorf, A., Kroneberg, G.: Alpha- and beta-sympathicomimetische Wirkungen am elektrisch gereizten isolierten Meerschweinchenileum. Naunyn-Schmiedeberg's Arch. Pharmacol, 267, 195–207 (1970)
Paton, W. D. M.: The response of the guinea-pig ileum to electrical stimulation by coaxial electrodes. J. Physiol. (Lond.) 127, 40–41 (1955)
Paton, W. D. M.: The action of morphine and related substances on contraction and on acetylcholine output of coaxially stimulated guinea-pig ileum. Br. J. Pharmacol. 12, 119–127 (1957)
Paton, W. D. M., Vizi, E. S.: The inhibitory action of noradrenaline and adrenaline on acetylcholine output by guinea-pig ileum longitudinal muscle strip. B. J. Pharmacol. 35, 10–28 (1969)
Seno, N., Nakazato, Y., Ohga, A.: Presynaptic inhibitory effects of catecholamines on cholinergic transmission in the smooth muscle of the chick stomach. Eur. J. Pharmacol. 51, 229–237 (1978)
Starke, K.: Alpha sympathomimetic inhibition of adrenergic and cholinergic transmission in the rabbit heart. Naunyn-Schmiedeberg's Arch. Pharmacol. 274, 18–24 (1972)
Starke, K.: Regulation of noradrenaline release by presynaptic receptor system. Rev. Physiol Biochem. Pharmacol. 77, 1–24 (1977)
Starke, K., Endo, T., Taube, H. D.: Relative pre- and postsynaptic potencies of α-adrenoceptor agonists in the rabbit pulmonary artery. Naunyn-Schmiedeberg's Arch. Pharmacol. 291, 55–78 (1975)
Taube, H. D., Starke, K., Borowski, E.: Presynaptic receptor system on the noradrenergic neurones of rat brain. Naunyn-Schmiedeberg's Arch. Pharmacol. 299, 123–141 (1977)
Werner, V., Starke, K., Schumann, H. J.: Actions of clonidie and 2-(2-methyl-6-ethyl-cyclohexylamino)-2-oxazoline on postganglionic autonomic nerves. Arch. Int. Pharmacol. 195, 282–290 (1972)
Wikberg, J.: Localization of adrenergic receptors in guinea-pig ileum and rabbit jejunum to cholinergic neurons and to smooth muscle cells. Acta Physiol. Scand. 99, 190–207 (1977)
Wikberg, J.: Differenciation between pre- and postjunctional α-receptors in guinea-pig ileum and rabbit aorta. Acta Physiol. Scand. 103, 225–239 (1978)
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Andréjak, M., Pommier, Y., Mouillé, P. et al. Effects of some α-adrenoceptor agonists and antagonists on the guinea-pig ileum. Naunyn-Schmiedeberg's Arch. Pharmacol. 314, 83–87 (1980). https://doi.org/10.1007/BF00498434
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DOI: https://doi.org/10.1007/BF00498434