Vasoconstrictory effects of adrenalin on the perfused head of the eel (Anguilla anguilla L.)

Adrenalin (5.0 x 10-5 M) increased gill vascular resistance up to 23.2 ± 6.8% in the isolated and perfused head of the european eel (Anguilla anguilla L.). This vasoactive response is nearly abolished by the α-adrenergic blocking agent phentolamine mesylate (5.0 x 10-5 M), while it is increased by the β-blocker propranolol (5.0 x 10-4 M). From these results it may be inferred that, in our experimental conditions, the major response to the catecholamine is a vasoconstriction mediated via α-adrenoceptors.