Transient elevation of cardiac beta-adrenoceptor responsiveness and receptor number in the streptozotocin-diabetic rat

C E Austin, R Chess-Williams

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

1. The effects on cardiac responsiveness of diabetes of up to 12 weeks duration has been examined in streptozotocin-pretreated rats. 2. Two weeks of diabetes resulted in a supersensitivity of isolated left atria and papillary muscles to isoprenaline, which was associated with an increase in the density of ventricular [3H]-dihydroalprenolol binding sites. 3. The beta-adrenoceptor supersensitivity was still evident in both tissues after 4 weeks of diabetes, but in left atria the supersensitivity was reduced compared with that observed at 2 weeks, while for papillary muscles it was greater than at 2 weeks. 4. Following 12 weeks of diabetes, responses of papillary muscles to isoprenaline were similar to controls, while beta-mediated responses of left atria were significantly depressed. 5. The alpha-adrenoceptor-mediated responses of cardiac tissues to phenylephrine were similar to controls following diabetes of 2 or 4 weeks duration. At 12 weeks, however, papillary muscle alpha-adrenoceptor-mediated responses were enhanced. The change in ventricular responsiveness to phenylephrine was not accompanied by any change in [3H]-prazosin binding to ventricular membranes. 6. The results demonstrate a transient elevation of cardiac beta-adrenoceptor sensitivity and receptor density during acute diabetes and illustrate the time- and tissue-dependence of diabetes-induced changes in cardiac adrenoceptor sensitivity.

Original languageEnglish
Pages (from-to)205-14
Number of pages10
JournalJournal of Autonomic Pharmacology
Volume12
Issue number4
DOIs
Publication statusPublished - 31 Aug 1992

Keywords

  • Animals
  • Binding Sites
  • Blood Glucose/analysis
  • Calcium/pharmacology
  • Diabetes Mellitus, Experimental/physiopathology
  • Dihydroalprenolol/metabolism
  • Female
  • Heart Atria/drug effects
  • Insulin/pharmacology
  • Isoproterenol/pharmacology
  • Myocardial Contraction/drug effects
  • Myocardium/metabolism
  • Papillary Muscles/drug effects
  • Phenylephrine/pharmacology
  • Prazosin/metabolism
  • Rats
  • Rats, Inbred Strains
  • Receptors, Adrenergic, beta/drug effects

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