Noradrenaline-induced basilar artery vasomotor response also varies in avian species (chickens and ducks)

<p>The basilar artery vasomotor response to noradrenaline (NA) differs between mammalian species (from α-receptor-mediated contraction in horses and β₁ receptor-mediated relaxation in pigs and cattle, to no response in mice), but has not been similarly evaluated in avian species. Accordingly, we aimed to compare the NA-induced response in basilar arteries from two poultry species, the chicken and the duck, to further elucidate species variation in vasomotor mechanisms. </p><p>Method: We measured vasomotor responses to NA under resting tension and after precontraction with 5-hydroxytriptamine (5-HT) with and without phentolamine (PHEN; a non-selective α-antagonist) pretreatment. Isoproterenol (ISO; a non-selective β-agonist) was also applied. </p><p>Results: NA-treated chicken basilar arteries showed contraction under resting tension, and relaxation followed by weak contraction after precontraction with 5-HT; the latter response was augmented with PHEN pretreatment and the relaxation did not significantly differ from maximal ISO-induced relaxation. NA-treated duck basilar arteries showed no response under resting tension, and relaxation after precontraction with 5-HT; the latter response was not augmented with PHEN pretreatment and did not significantly differ from maximal ISO-induced relaxation. </p><p>Conclusion: We demonstrated that NA-induced basilar artery vasomotion response differs between these poultry species. Chicken basilar arteries might possess α &gt; β₁ receptors (involved in contraction and relaxation, respectively), and that duck basilar arteries might possess β₁ receptors (involved in relaxation).</p>