Abstract
1 Guinea-pig gall bladder strips were contracted by (-)-noradrenaline, 10(-5) M, and by field stimulation at 5 Hz (in the absence or presence of 10(-6) M atropine) and relaxed to 10(-5) M (-)-isoprenaline. (-)-Adrenaline, 10(-5) M, predominantly contracted, but sometimes relaxed, this preparation. 2 In the presence of 10(-6) M phentolamine, contractions to (-)-noradrenaline and to (-)-adrenaline were reversed to relaxations. The relaxations produced by (-)-isoprenaline were unaltered. In the presence of 10(-6) M propranolol, contractions to (-)-noradrenaline increased in magnitude, relaxations to (-)-adrenaline were reversed to contractions, and relaxations to (-)-isoprenaline were abolished. These results demonstrate the presence of postsynaptic alpha-adrenoceptors which mediate contractions, and postsynaptic beta-adrenoceptors which initiate relaxations, in the guinea-pig gall bladder. 3 The contractile responses to continuous field stimulation for 5 min at 5 Hz in Krebs solution alone were reduced in magnitude by propranolol, 10(-6) M. In the presence of 10(-6) M atropine (added to eliminate the cholinergic component of the response), propranolol, 10(-6) M, had no effect on responses to stimulation at 5 Hz. Thus propranolol reduced the response to cholinergic stimulation in this tissue; the basis of this effect is unclear. In the absence or presence of atropine (10(-6) M), the responses to 5 Hz were smaller in magnitude in the presence than absence of phentolamine, 10(-6) M. This suggests that the responses to field stimulation of the guinea-pig gall bladder may, in part, be due to the release of endogenous noradrenaline which acts at postsynaptic alpha-adrenoceptors.
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Selected References
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- Baumgarten H. G., Lange W. Extrinsic adrenergic innervation of the extrahepatic biliary duct system in guinea-pigs, cats and rhesus monkeys. Z Zellforsch Mikrosk Anat. 1969 Sep 22;100(4):606–615. doi: 10.1007/BF00344379. [DOI] [PubMed] [Google Scholar]
- Davison J. S., Al-Hassani M., Crowe R., Burnstock G. The non-adrenergic, inhibitory innervation of the guinea-pig gallbladder. Pflugers Arch. 1978 Oct 18;377(1):43–49. doi: 10.1007/BF00584372. [DOI] [PubMed] [Google Scholar]
- Davison J. S., Fösel S. Interactions between vagus nerve stimulation and pentagastrin or secretin on the guinea pig gallbladder. Digestion. 1975;13(4):251–254. doi: 10.1159/000197715. [DOI] [PubMed] [Google Scholar]
- Impicciatore M. Occurrence of H1- and H2-histamine receptors in the guinea-pig gall bladder in situ. Br J Pharmacol. 1978 Oct;64(2):219–222. doi: 10.1111/j.1476-5381.1978.tb17292.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Persson C. G. Adrenoceptors in the gall bladder. Acta Pharmacol Toxicol (Copenh) 1972;31(3):177–185. doi: 10.1111/j.1600-0773.1972.tb00711.x. [DOI] [PubMed] [Google Scholar]