Tenner T E, Ramanadham S, Yang M C, Pang P K
Can J Physiol Pharmacol. 1983 Oct;61(10):1162-7. doi: 10.1139/y83-173.
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).
已知牛甲状旁腺激素及其N端（1-34）肽片段（bPTH-(1-34)）在大鼠中具有直接的降压活性。本研究的目的是确定bPTH-(1-34)是否也具有直接的变时作用。体内研究表明，bPTH-(1-34)在大鼠中确实产生了变时效应，包括直接成分以及与其降压作用相关的反射性心动过速。对离体右心房的体外研究表明，虽然bPTH-(1-34)没有正性肌力作用，但它确实产生了显著的变时效应，这些效应是直接且剂量依赖性的。发现bPTH-(1-34)的效力与异丙肾上腺素相似，然而，在最大程度增加心房率方面，它的效力仅为异丙肾上腺素的三分之一。在bPTH-(1-34)的变时作用之前，心房环磷酸腺苷（cAMP）有轻微但显著的增加。
