The adrenergic nerve supply to the female reproductive tract of the cat

Pilot studies on the fluorescence histochemistry of the adrenergic innervation to the female reproductive tract in different mammals revealed a conspicuously well developed innervation in the cat. Moreover, the female genital tract of the cat is studied extensively with regard to the pharmacology of adrenergic mechanisms. An exact knowledge of the adrenergic innervation apparently would make the cat a particularly suitable model for functional studies on the involvement of neuronal adrenergic mechanisms in the reproductive tract. Fluorimetrically, noradrenaline was the only catecholamine occurring in measurable amounts in nonpregnant cats. The amine seemed to have an exclusively neuronal distribution, although a comparatively small fraction may be also located in “chromaffin” cells present in relation to ganglion formations. A considerable number of adrenergic nerve terminals were found in all organs of the reproductive tract. Consistent numbers of these terminals were directed to various structures forming the ovarian parenchyma and to the smooth muscle coats of the oviduct, uterus, and vagina. The rest of the innervation seemed to be of vasomotor nature. The histochemical results agree well with the high level of noradrenalin, 1.22–4.93 μg/gm, found in the different organs. Denervation experiments revealed that the postganglionic sympathetic innervation reaches the oviduct, uterus, and vagina partly by way of the hypogastric nerves, and partly by way of short adrenergic neurons originating from adrenergic ganglia that could be directly visualized in the region of the uterovaginal junction. The ovarian adrenergic innervation seemed to arise more proximally, probably directly from the sympathetic chain.