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. 1987 Aug;91(4):789–798. doi: 10.1111/j.1476-5381.1987.tb11277.x

Mechanical and electrical responses to alpha-adrenoceptor activation in the circular muscle of guinea-pig stomach.

S Chihara 1, T Tomita 1
PMCID: PMC1853569  PMID: 2889489

Abstract

1 In the circular muscle of the corpus region of the guinea-pig stomach, the effects of catecholamines on mechanical activity were studied with simultaneous recording of membrane potential by use of intracellular microelectrodes. In order to investigate responses mediated through alpha-adrenoceptors, the beta-adrenoceptors were blocked by propranolol (10(-6) M) in most experiments. 2 Adrenaline (less than 10(-6) M) produced a monophasic contraction with little change in membrane potential. At higher concentrations (greater than 10(-5) M), adrenaline usually produced an early transient contraction followed by a slow tonic contraction. During the early phase, the membrane was hyperpolarized and slow waves were reduced in amplitude. 3 The phasic contractions superimposed on the late slow phase of the contractile response were higher in frequency and larger in amplitude than in controls before adrenaline application. These changes were associated with an increase in the amplitude and frequency of slow waves, and with a spike-like component appearing on the top of each slow wave. 4 Adrenaline-induced changes in mechanical and electrical activity were inhibited by prazosin, but largely unaffected by yohimbine. In some preparations, there was a transient weak inhibition of phasic contraction before muscle tone was increased by adrenaline, and this became more pronounced in the presence of yohimbine. 5 Phenylephrine, selective for alpha 1-receptors, produced responses very similar to those of adrenaline, whereas agonists selective for alpha 2-receptors, clonidine and B-HT 920, produced only a small slow contraction without any clear change in membrane potential.(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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

  1. Bailey D. M. Inhibitory and excitatory effects of sympathomimetic amines on muscle strips from the stomach of the guinea-pig. Br J Pharmacol. 1971 Feb;41(2):227–238. doi: 10.1111/j.1476-5381.1971.tb08024.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Daniel E. E., Jager L. P., Jury J. Catecholamines release mediators in the opossum oesophageal circular smooth muscle. J Physiol. 1987 Jan;382:489–508. doi: 10.1113/jphysiol.1987.sp016380. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Guimarães S. Alpha excitatory, alpha inhibitory and beta inhibitory adrenergic receptors in the guinea-pig stomach. Arch Int Pharmacodyn Ther. 1969 May;179(1):188–201. [PubMed] [Google Scholar]
  4. Haffner J. F. -adrenergic receptor stimulation with phenylephrine in rabbit fundus muscle exposed to carbachol. Acta Pharmacol Toxicol (Copenh) 1972;31(1):121–128. doi: 10.1111/j.1600-0773.1972.tb00704.x. [DOI] [PubMed] [Google Scholar]
  5. Haffner J. F. The adrenergic receptors in isolated rabbit stomach muscle. Acta Pharmacol Toxicol (Copenh) 1971;29(4):327–338. doi: 10.1111/j.1600-0773.1971.tb00594.x. [DOI] [PubMed] [Google Scholar]
  6. Ito Y., Kuriyama H. Responses to field stimulation of the smooth muscle cell membrane of the guinea pig stomach. Jpn J Physiol. 1975;25(3):333–344. doi: 10.2170/jjphysiol.25.333. [DOI] [PubMed] [Google Scholar]
  7. Langer S. Z., Hicks P. E. Alpha-adrenoreceptor subtypes in blood vessels: physiology and pharmacology. J Cardiovasc Pharmacol. 1984;6 (Suppl 4):S547–S558. doi: 10.1097/00005344-198406004-00001. [DOI] [PubMed] [Google Scholar]
  8. Magaribuchi T., Obu T., Sakamoto Y., Yamamoto Y. Some electrical properties of the slow potential changes recorded from the guinea pig stomach in relation to drug actions. Jpn J Physiol. 1972 Jun;22(3):333–352. doi: 10.2170/jjphysiol.22.333. [DOI] [PubMed] [Google Scholar]
  9. Ohba M., Sakamoto Y., Tomita T. Effects of sodium, potassium and calcium ions on the slow wave in the circular muscle of the guinea-pig stomach. J Physiol. 1977 May;267(1):167–180. doi: 10.1113/jphysiol.1977.sp011806. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Ohkawa H. Evidences for alpha excitatory action of catecholamines on the electrical activity of the guinea-pig stomach. Jpn J Physiol. 1976;26(1):41–52. doi: 10.2170/jjphysiol.26.41. [DOI] [PubMed] [Google Scholar]
  11. Sahyoun H. A., Costall B., Naylor R. J. Benzamide action at alpha 2-adrenoceptors modifies catecholamine-induced contraction and relaxation of circular smooth muscle from guinea-pig stomach. Naunyn Schmiedebergs Arch Pharmacol. 1982 Apr;319(1):8–11. doi: 10.1007/BF00491470. [DOI] [PubMed] [Google Scholar]
  12. Sahyoun H. A., Costall B., Naylor R. J. Catecholamines act as alpha 2-adrenoceptors to cause contraction of circular smooth muscle of guinea-pig stomach. J Pharm Pharmacol. 1982 Jun;34(6):381–385. doi: 10.1111/j.2042-7158.1982.tb04734.x. [DOI] [PubMed] [Google Scholar]
  13. Yamaguchi T., Tomita T. Mechanical responses to catecholamines in isolated strips of the guinea-pig stomach muscle. Jpn J Pharmacol. 1974 Dec;24(6):911–922. doi: 10.1254/jjp.24.911. [DOI] [PubMed] [Google Scholar]
  14. el-Sharkawy T. Y., Szurszewski J. H. Modulation of canine antral circular smooth muscle by acetylcholine, noradrenaline and pentagastrin. J Physiol. 1978 Jun;279:309–320. doi: 10.1113/jphysiol.1978.sp012346. [DOI] [PMC free article] [PubMed] [Google Scholar]

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