Skip to main content
NCBI home page
British Journal of Pharmacology logoLink to British Journal of Pharmacology
. 1989 Oct;98(2):552–556. doi: 10.1111/j.1476-5381.1989.tb12629.x

Demonstration in Tupaia papillary muscle preparations of alpha-adrenoceptors mediating positive inotropic effects: comparison with guinea-pigs.

T Koga 1, Y Shiraki 1, K Sakai 1
PMCID: PMC1854701  PMID: 2573402

Abstract

1. Positive inotropic responses to alpha- and beta-adrenoceptor agonists of isolated papillary muscles from the tree shrew (Tupaia), were compared with those from guinea-pigs. 2. In Tupaia, the concentration-response curve for phenylephrine, unlike that for isoprenaline, was not affected by pindolol in a concentration (10(-8) M) sufficient to block beta-adrenoceptor-mediated responses, but it was significantly shifted to the right by phentolamine (10(-6) M). In guinea-pig papillary muscles, however, the concentration-response curve for phenylephrine, like that for isoprenaline, was shifted to the right by pindolol (10(-8) M) but was unaltered by phentolamine (10(-6) M). Furthermore, when the mean concentrations of agonists inducing maximal positive inotropic responses were compared (relative to that of isoprenaline = 1.0), phenylephrine was found to be only slightly less potent (0.84 +/- 0.04; n = 5) in Tupaia and much less potent (0.33 +/- 0.06; n = 5) in the guinea-pig. 3. Although in Tupaia papillary muscles the increase in developed tension induced by a combination of phenylephrine and isoprenaline did not significantly differ from that by phenylephrine alone, it was approximately 3 times larger than that produced by phenylephrine alone in guinea-pigs. 4. These results indicate that in papillary muscles from Tupaia, unlike the guinea-pig, the positive inotropic effects of phenylephrine can be mediated by alpha-adrenoceptors.

Full text

PDF
552

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ask J. A., Stene-Larsen G., Helle K. B., Resch F. Functional alpha-adrenoceptors in human atrial preparations in the presence of beta-receptor blockade. Acta Physiol Scand. 1987 Nov;131(3):439–445. doi: 10.1111/j.1748-1716.1987.tb08259.x. [DOI] [PubMed] [Google Scholar]
  2. Benfey B. G. Function of myocardial alpha-adrenoceptors. Life Sci. 1982 Jul 12;31(2):101–112. doi: 10.1016/0024-3205(82)90421-0. [DOI] [PubMed] [Google Scholar]
  3. Davey M. J. Alpha adrenoceptors--an overview. J Mol Cell Cardiol. 1986 Nov;18 (Suppl 5):1–15. doi: 10.1016/s0022-2828(86)80457-6. [DOI] [PubMed] [Google Scholar]
  4. Goodman M. Phyletic position of tree shrews. Science. 1966 Sep 23;153(3743):1550–1550. doi: 10.1126/science.153.3743.1550-a. [DOI] [PubMed] [Google Scholar]
  5. McClure H. M., Keeling M. E., Olberding B., Hunt R. D., Melendez L. V. Natural Herpesvirus hominis infection of tree shrews (Tupaia glis). Lab Anim Sci. 1972 Aug;22(4):517–521. [PubMed] [Google Scholar]
  6. Moore G. W., Goodman M. A set theoretical approach to immunotaxonomy: analysis of species comparisons in modified Ochterlony plates. Bull Math Biophys. 1968 Jun;30(2):279–289. doi: 10.1007/BF02476695. [DOI] [PubMed] [Google Scholar]
  7. Noyes W. F. Carcinogen-induced sarcoma in the primitive primate, Tupaia glis. Proc Soc Exp Biol Med. 1968 Feb;127(2):594–596. doi: 10.3181/00379727-127-32750. [DOI] [PubMed] [Google Scholar]
  8. Sakai K., Shiraki Y., Tatsumi T., Tsuji K. The actions of 5-hydroxytryptamine and histamine on the isolated ileum of the tree shrew (Tupaia glis). Br J Pharmacol. 1979 Jul;66(3):405–408. doi: 10.1111/j.1476-5381.1979.tb10845.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Schwaier A. Breeding tupaias (Tupaia belangeri) in captivity. Z Versuchstierkd. 1973;15(5):255–271. [PubMed] [Google Scholar]
  10. Schümann H. J., Endo M., Wagner J. Positive inotropic effects of phenylephrine in the isolated rabbit papillary muscle mediated both by alpha- and beta-adrenoceptors. Naunyn Schmiedebergs Arch Pharmacol. 1974;284(2):133–148. doi: 10.1007/BF00501118. [DOI] [PubMed] [Google Scholar]
  11. Wagner J., Brodde O. E. On the presence and distribution of alpha-adrenoceptors in the heart of various mammalian species. Naunyn Schmiedebergs Arch Pharmacol. 1978 May;302(3):239–254. doi: 10.1007/BF00508293. [DOI] [PubMed] [Google Scholar]
  12. Wenzel D. G., Su J. L. Interactions between sympathomimetic amines and blocking agents on the rat ventricle strip. Arch Int Pharmacodyn Ther. 1966 Apr;160(2):379–389. [PubMed] [Google Scholar]
  13. Williamson K. L., Broadley K. J. Characterization of the alpha-adrenoceptors mediating positive inotropy of rat left atria by use of selective agonists and antagonists. Arch Int Pharmacodyn Ther. 1987 Feb;285(2):181–198. [PubMed] [Google Scholar]

Articles from British Journal of Pharmacology are provided here courtesy of The British Pharmacological Society

RESOURCES