The effects of novel catecholamines on blood pressure and ventilation in rainbow trout

Abstract

6-Nitrodopamine (6-ND) is a newly identified catecholamine released from vascular tissues. Its release is significantly reduced upon pharmacological blockade of NO synthesis with Nx-nitro-L-arginine methyl ester (L-NAME), and it functions as a vasodilator through dopamine D2-like receptor antagonism. Elevated blood pressure induced by L-NAME administration coincides with decreased heart rate, suggesting a role for 6-ND. Recently, other NO-catecholamines of endogenous production were identified in rabbit atria and ventricles, including a novel catecholamine class known as 6-cyanodopamine, also identified in human platelets. The evaluation of their physiological role and release mechanisms remains to be investigated. In fish, catecholamine release during acidosis affects ventilatory response, while exogenous catecholamines administered to hypoxic trout elicit hypoventilation. This project investigates the endogenous production of new catecholamines and their physiological role in the cardiorespiratory function of rainbow trout, advancing our understanding of cardiovascular physiology in fishes and the significance of novel catecholamines.