Chronotropic actions of bPTH-(1-34) in the right atrium of the rat.

Abstract

Bovine parathyroid hormone and its N-terminal (1-34) peptide fragment (bPTH-(1-34] are known to possess direct hypotensive activity in the rat. The purpose of the present study was to determine if bPTH-(1-34) possessed a direct chronotropic action as well. In vivo studies revealed that bPTH-(1-34) did produce a chronotropic effect in the rat comprising both a direct component as well as a reflex tachycardia related to its hypotensive actions. In vitro studies of isolated right atria indicated that while bPTH-(1-34) had no positive inotropic effect, it did produce significant chronotropic effects which were direct and dose-dependent. The potency of bPTH-(1-34) was found to be similar to that of isoproterenol, however, it was only one-third as effective as isoproterenol in maximally increasing atrial rate. A slight but significant increase in atrial cyclic AMP was generated prior to the chronotropic actions of bPTH-(1-34).

• Authors: T E Tenner Jr, S Ramanadham, M C Yang, P K Pang
• Journal: Canadian journal of physiology and pharmacology (Can J Physiol Pharmacol) Vol. 61 Issue 10 Pg. 1162-7 (Oct 1983) ISSN: 0008-4212 [Print] Canada
• PMID: 6315205 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Parathyroid Hormone
• Reserpine
• Propranolol
• Cyclic AMP
• Isoproterenol

Topics

• Adrenergic Fibers (physiology)
• Animals
• Cyclic AMP (physiology)
• Heart (drug effects)
• Heart Rate (drug effects)
• Isoproterenol (pharmacology)
• Male
• Parathyroid Hormone (antagonists & inhibitors, pharmacology)
• Propranolol (pharmacology)
• Rats
• Reserpine (pharmacology)