Abstract
The effects of the opioid receptor agonist RX783006 and of the opioid receptor partial agonist (+)-meptazinol have been examined on electrically-induced twitch responses of the guinea-pig isolated ileum and of the mouse isolated vas deferens. Log10 concentration-tissue state curves were determined for (+)-meptazinol and for RX783006, alone, in combination and, when appropriate, in the presence of naloxone (30 nM). Analysis of these log10 concentration-tissue state curves using the null equations derived and verified in the previous paper allows quantitation of the characteristics of the interaction of (+)-meptazinol with the opioid receptors in these tissues. The results indicate that the apparent differences in the actions of (+)-meptazinol on isolated electrically-stimulated guinea-pig ileum and mouse vas deferens can be accounted for without the need to postulate differences between mu-opioid receptors in these two tissues.
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Selected References
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- Bill D. J., Hartley J. E., Stephens R. J., Thompson A. M. The antinociceptive activity of meptazinol depends on both opiate and cholinergic mechanisms. Br J Pharmacol. 1983 May;79(1):191–199. doi: 10.1111/j.1476-5381.1983.tb10512.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Duchesne R. J., Goodall J., Hughes I. E. Pharmacological effects of meptazinol and its enantiomers on guinea-pig ileum and mouse vas deferens. J Pharm Pharmacol. 1984 Aug;36(8):560–562. doi: 10.1111/j.2042-7158.1984.tb04455.x. [DOI] [PubMed] [Google Scholar]
- Hughes I. E., Mackay D. Quantification of the characteristics of antagonists exhibiting both competitive antagonism and functional interaction. Br J Pharmacol. 1985 May;85(1):271–275. doi: 10.1111/j.1476-5381.1985.tb08856.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kenakin T. P., Black J. W. The pharmacological classification of practolol and chloropractolol. Mol Pharmacol. 1978 Jul;14(4):607–623. [PubMed] [Google Scholar]
- Mackay D. A general analysis of the receptor-drug interaction. Br J Pharmacol Chemother. 1966 Jan;26(1):9–16. doi: 10.1111/j.1476-5381.1966.tb01805.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pasternak G. W. High and low affinity opioid binding sites: relationship to mu and delta sites. Life Sci. 1982 Sep 20;31(12-13):1303–1306. doi: 10.1016/0024-3205(82)90367-8. [DOI] [PubMed] [Google Scholar]
- Sayre L. M., Portoghese P. S., Takemori A. E. Difference between mu-receptors in the guinea pig ileum and the mouse vas deferens. Eur J Pharmacol. 1983 May 20;90(1):159–160. doi: 10.1016/0014-2999(83)90232-7. [DOI] [PubMed] [Google Scholar]
- Schulz R., Wüster M. Are there subtypes (isoreceptors) of multiple opiate receptors in the mouse vas deferens? Eur J Pharmacol. 1981 Nov 19;76(1):61–66. doi: 10.1016/0014-2999(81)90009-1. [DOI] [PubMed] [Google Scholar]
- Stephens R. J., Waterfall J. F., Franklin R. A. A review of the biological properties and metabolic disposition of the new analgesic agent, meptazinol. Gen Pharmacol. 1978;9(2):73–78. doi: 10.1016/0306-3623(78)90002-2. [DOI] [PubMed] [Google Scholar]
- Takemori A. E., Portoghese P. S. Comparative antagonism by naltrexone and naloxone of mu, kappa, and delta agonists. Eur J Pharmacol. 1984 Sep 3;104(1-2):101–104. doi: 10.1016/0014-2999(84)90374-1. [DOI] [PubMed] [Google Scholar]
- Wood P. L., Richard J. W., Thakur M. Mu opiate isoreceptors: differentiation with kappa agonists. Life Sci. 1982 Nov 15;31(20-21):2313–2317. doi: 10.1016/0024-3205(82)90145-x. [DOI] [PubMed] [Google Scholar]