Studies on Adrenergic and Gholinergic Receptors in the Isolated Hearts of Lampetra fluviatilis (Cyclostomata) and Pleuronectes platessa (Teleostei)

Abstract

Abstract An attempt has been made to characterize the adrenergic and cholinergic receptors in the isolated hearts of the lamprey Lampetra fluviatilis and the plaice Pleuronectes platessa. In both species hearts respond to adrenaline, noradrenaline and isoprenaline in the same way as the isolated mammalian heart and the effect of these agents is blocked by a β‐receptor blocking agent. The adrenergic receptors thus are of the β‐type. The cholinergic receptors are different in the heart of the two species. In the lamprey heart the cholinergic receptors are of the curaresensitive type and these receptors seem to be the only existing type of cholinergic receptors in the heart of this species. In the plaice heart, however, the cholinergic receptors are of the same nature as in the mammalian heart i.e. of the hexamethonium and the atropine sensitive type. The effects of nicotine and tyramine on the isolated lamprey and plaice hearts have been discussed with regard to the existence and localization of catecholamines in the hearts of these species.