Drug induced changes in cardio-vascular parameters in the Atlantic cod,Gadus morhua

Abstract

Ventral (VAP) and dorsal (DAP) aortic blood pressure, heart rate (HR) and cardiac output (\(\dot Q\)) were recorded simultaneously in unanaesthetized Atlantic cod, and the effects of vasoactive drugs on the cardio-vascular parameters studied. Mean resting values for the parameters were VAP=4,39 kPa, DAP=2,49 kPa, HR=41 beats/min, and\(\dot Q\) = 29,1 ml/min×kg. Adrenaline constricted the systemic vasculature, dilated the branchial vasculature and caused a decrease of HR and\(\dot Q\) due to a cholinergic reflex. After atropine pre-treatment this reflex was abolished, and the effect of adrenaline on blood pressure enhanced. A small decrease in\(\dot Q\) persisted after atropine, presumably reflecting the effect of an increased end-systolic afterload.