Vascular reactivity of the efferent branchial arteries of the lemon shark, Negaprion queenslandicus

Abstract

1. Efferent branchial artery tissue rings from Negaprion queenslandicus were used to examine the effects of adrenergic and cholinergic drugs on the vasculature.

2. The presence of α- and β-adrenoceptors were demonstrated.

3. Adrenaline and noradrenaline produced variable, including biphasic, responses.

4. Acetylcholine produced concentration-dependent contractions in the presence of a predominantly intact endothelium.