Immunolocalization of alpha(1A)-adrenoceptors in rat and human epididymis

Immunohistochemistry was conducted to analyze the cellular localization of alpha(1A)-adrenoceptors along rat and human epididymis. ADR-A, a polyclonal antibody that recognizes the specific C-terminal region of alpha(1A)-adrenoceptors, immunostained this adrenoceptor subtype in smooth muscle cells surrounding the epididymal tubules and interstitial blood vessels and in subpopulations of epithelial cells from adult rat and human caput and cauda epididymidis. the same cell types from rat epididymidis were immunostained by ADR-1, a polyclonal antibody that recognizes a common region of the three alpha(1)-adrenoceptor subtypes, alpha(1A), alpha(1B), and alpha(1D). Immunostaining with both antibodies was also conducted in adult rat and human vas deferens and seminal vesicle used as positive controls because of the abundance of alpha(1A)-adrenoceptors in these tissues. ADR-A- and ADR-1-positive immunostaining was differentially distributed depending on the antibody, method of tissue fixation (Bouin-fixed and fresh frozen tissues), species (rat and human), tissue (caput and cauda epididymidis), and age (immature and adult rats) analyzed. This is the first report immunolocalizing alpha(1A)-adrenoceptor along rat and human epididymis. the presence of this adrenoceptor subtype in epididymal smooth muscle and epithelial cells indicates their contribution to smooth muscle contractile responses and a possible role in the absorptive and/or secretory activities of the epithelium lining the epididymal duct. Taken together, our results should contribute to a better understanding of the physiological role of alpha(1)-adrenoceptors in the epididymidis and the importance of the sympathetic nervous system for male (in)fertility.Universidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, Sect Expt Endocrinol,INFAR, BR-04044020 São Paulo, BrazilUniv N Carolina, Labs Reprod Biol, Dept Cell & Dev Biol & Pediat, Chapel Hill, NC 27599 USAUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, Sect Expt Endocrinol,INFAR, BR-04044020 São Paulo, BrazilWeb of Scienc

Serotonin concentration, synthesis, cell origin, and targets in the rat caput epididymis during sexual maturation and variations associated with adult mating status: Morphological and biochemical studies

The caput epididymis of some mammals contains large quantities of serotonin whose origin, targets, and physiological variations have been poorly studied. We combined morphological and biochemical techniques to begin approaching these aspects of serotonin in the rat caput epididymis. Serotonin immunostaining was detected in mast, epithelial, and neuroendocrine cells. Epithelial cells displayed immunoreactivity to 5HT(1A), 5HT(2A), and 5HT(3) serotonin receptors. Endothelial and mast cells labeled positive for 5HT(1B) serotonin receptors and spermatozoa displayed 5HT2A and 5HT3 serotonin receptor immunoreactivity. Epithelial, endothelial, and mast cells stained positive for serotonin transporters. Only epithelial cells showed tryptophan hydroxylase immunoreactivity; this enzyme catalyzes the limiting step in the serotonin synthetic pathway. in addition, Western blot analyses of caput homogenates documented the presence of 2 protein bands (approximate to 51 kd and 48 kd) that were immunoreactive for tryptophan hydroxylase. Chromatographic analyses documented the presence of tryptophan hydroxylase in the caput, and showed that both its activity and serotonin availability increased with sexual maturation and decreased following p-chlorophenylalanine treatment, an inhibitor of tryptophan hydroxylase activity. Interestingly, serotonin concentration and tryptophan hydroxylase activity tended to be higher in breeding males than in those with no mating experience. We think that these results support the existence of a local serotoninergic system in the rat caput epididymis that might regulate some aspects of male reproductive function.Natl Autonomous Univ Mexico, Biomed Res Inst, Dept Cell Biol & Physiol, Mexico City 04510, DF, MexicoUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, Sect Expt Endocrinol, São Paulo, BrazilNatl Autonomous Univ Mexico, Fac Sci, Dept Reprod Biol, Mexico City 04510, DF, MexicoXXI Century Natl Med Ctr, Unit Med Invest Neurol Dis, Mexico City, DF, MexicoUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, Sect Expt Endocrinol, São Paulo, BrazilWeb of Scienc