Adrenergic receptors of isolated snake atria

K. W. Chiu, J. S.K. Sham

Research output: Contribution to journalArticle

Abstract

1. 1. Cardiac adrenergic receptors in snakes were examined using an isolated atria preparation of Naja naja and Ptyas korros. Treatments included an examination of the atrial responses to selective α- and β-adrenergic agonists and antagonists. 2. 2. In both species, both phenylephrine and isoproterenol produced dose-dependent increases in the atrial beating rate and tension. Phenylephrine-induced increases were characterized with a high affinity and low affinity components. 3. 3. These positive chronotropic and inotropic effects produced by phenylephrine and isoproterenol were abolished with propranolol and in the phenylephrine-induced response phentolamine also attenuated the low affinity response and blocked the high affinity response. 4. 4. With catecholamines depletion via 6-OH dopamine or reserpine, the high affinity component in the phenylephrine-induced response was no longer observed. 5. 5. It is concluded that β-adrenoceptors are the predominant post-synaptic adrenoceptors in snake atria. Stimulatory presynaptic α-adrenoceptors for modulating noradrenaline release may also be present.

Original languageEnglish (US)
Pages (from-to)445-450
Number of pages6
JournalComparative Biochemistry and Physiology. Part C, Comparative
Volume81
Issue number2
DOIs
StatePublished - 1985
Externally publishedYes

ASJC Scopus subject areas

  • Immunology
  • Pharmacology

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