Release of Noradrenaline from the Dog Heart In Situ after Intravenous and Intracoronary Administration of 5‐Hydroxytryptamine

Publisher Website
Google Scholar
Abstract
The following experiments have been carried out in order to establish the validity of the hypothesis that the cardiac stimulatory effects of 5‐hydroxytryptamine (5‐HT) are mediated by catecholamines. Release of cardiac noradrenaline (NA) has been observed after administration of 5‐HT either intravenously or intracoronarily. After labelling the heart with3H‐5‐HT, it was possible to release this amine by cardioaccelerator nerve stimulation even after treatment with an adrenergic β blocker. It is concluded that the cardiac stimulatory effects of 5‐HT are mediated by NA; this NA is mainly derived from sympathetic nerve endings by intra‐neuronal exchange for 5‐HT.