Adrenergic activity of the avian oviduct in vivo

Abstract

The effect of noradrenaline or isoproterenol, alone or in the presence of an alpha (phenoxybenzamine) or beta (propranolol) adrenergic blocking drugs on the oviducts of anesthetized laying hens was investigated. The results show that both alpha and beta adrenergic activity is present in the avian oviduct with the exception of the uterus which does not appear to have alpha excitatory activity. Norepinephrine induced a strong contraction followed by a brief relaxation period in the infundibulum, magnum and is thmus; administration of phenoxybenzamine blocked this response in all the three segments, indicating the presence of alpha adrenergic receptors. The uterus, however, exhibited an inhibitory response in the majority of the hens and this response was not affected by the administration of phenoxybenzamine. Isoproterenol always induced relaxation in all the four segments of the oviduct. This response was blocked by propranolol, a beta adrenergic blocker, indicating the presence of beta adrenergic receptors. The role of autonomic nerves innervating the reproductive tract in the regulation of reproduction is discussed.