Pharmacological and histological evidence for adrenergic innervation of the myoid cells in the rat seminiferous tubule.

Although the existence of seminiferous tubule contractions attributed to peritubular myoid cells is established, the control of the contractions is poorly understood. In this communication, it is shown that the rat seminiferous tubule responds to autonomic drugs and to stimulation of the perivascular nerve running along the spermatic vessels, by means of recording the intratubular pressure with a servo-null micropressure measuring device. Furthermore, the presence of nerve fibers close to the myoid cells is shown using a silver impregnation technique. Furthermore, the nature of the neurotransmitter contained in synaptic vesicles using 5-hydroxydopamine and L-DOPA as markers of adrenergic nerve elements with electron microscopy is shown in this report. It is concluded that there are adrenergic alpha- and beta-receptors and muscarinic receptors in myoid cells of the rat seminiferous tubule and that the contractions of seminiferous tubules are regulated by adrenergic nerve fibers.