Original Paper 159 Original Paper ©2003, European Journal of Histochemistry The innervation pattern in the buffalo testis was determined by using histochemical and immunohistochemical methods. Nerves were concentrated in the tunica albuginea and sep- tula testis, and did not show an uniform distribution. The tunica albuginea at the lateral and medial sides and at the free border of the testis is most densely innervated than at the epididymal border. At the cranial pole thick nerve bun- dles were observed between albugineal vessels and muscle bundles. Rare parenchymal nerves were found in perivascu- lar position between seminiferous tubules and their occur- rence is confined to lobules at the cranial and caudal tes- ticular poles. An intense NPY immunoreactivity occurred in nerve bundles and in solitary varicose fibres. Nerves were concentrated in the tunica albuginea at the lateral and medial side and at the free border of the testis, and in the lobules at the cranial and caudal testicular poles. Sub P immunoreactivity was occasionally detected in some thicker nerve bundles and solitary fibers, in the tunica albuginea and in the wall of blood vessels, showing a similar distribu- tion but less intensity and density than NPY immunoreactiv- ity. TH immunoreactivity stained nerve fibers in the buffalo testis with a distribution pattern similar to that obtained with general neuronal markers. The histochemical reaction for AchE was negative, so cholinergic fibers cannot be detected in the buffalo testis. The histochemical NADPHd reaction stained rare nitrergic nerve bundles and solitary fibers. The majority of NADPHd activity was confined to the vascular endothelium, and rarely to the interstitial Leydig cells, where- as the Sertoli and germ cells did not show any reaction. Key words: autonomous innervation, testis, buffalo, immuno- histochemistry. Correspondence: Paolo de Girolamo, Dipartimento di Strut- ture, Funzioni e Tecnologie Biologiche, Università di Napoli “Federico II”, via Veterinaria 1, 80137 Naples, Italy. Phone: international +39.081.5644204 Fax: international +39.081.56230. E-mail: degirola@unina.it Paper accepted on November 15, 2002. European Journal of Histochemistry 2003; vol. 47 issue 2 [Apr-Jun]:159-164 The autonomous innervation of the buffalo (Bubalus bubalis) testis. An immunohistochemical study P. de Girolamo*, C. Costagliola, C. Lucini, G. Gargiulo, L. Castaldo Dipartimento di Strutture, Funzioni e Tecnologie Biologiche; Università di Napoli “Federico II”, Naples, Italy T he autonomic nervous system has an important role in the regulation of the mammalian male reproductive functions (for review, see Dail 1993). It is a general acknowledge that the intrinsic testicular innervation is mainly associated with blood vessels and involved in the control of testicular blood flow and temperature (Hodson, 1970). In species with smooth muscle in the testicular tunica albuginea and visceral serosa the sympathetic nervous system may participate in the extrusion of spermatozoa from the testis (Davies and Langford, 1971; Bell and McLean, 1973). The organization and the chemical coding of tes- ticular nerve fibers of mammals have been the sub- ject of many morphological and physiological stud- ies, mostly focused on laboratory mammals (Greenberg et al., 1985; Campos et al., 1990; Pro- perzi et al., 1992) and man (Vaalasti et al., 1986; Taino, 1994). Other mammalian species including large, breeding mammals have largerly been ignored, altough there is some evidence suggesting the exis- tence of distinct species-dependent variations in the neurochemical coding of nerve fibers innervating the testis (Wrobel and Abu-Ghali, 1997; Wrobel and Brandl, 1998; Wrobel and Moustafa, 2000). Particularly, in the testis of bull, pig and donkey local differences in the innervation quality and quantity have been reported.The porcine testis was complete- ly devoid of intrinsic innervation in adult subject, while displays evident age-related changes (Wrobel and Brandl, 1998). No cholinergic and myelinated fibers have been detected in this species, and NPY was the dominating neuropeptide in the testis (Wrobel and Brandl, 1998). The testicular innerva- tion pattern in the donkey is not uniform, is avoid of cholinergic fibers, and shows NPY as the most fre- quent peptidergic transmitter (Wrobel and Kamel- Moustafa, 2000). In bovine testis there was no evi- dence for a cholinergic innervation,and about half of the testicular nerves are NPY immuno-positive (Wrobel and Abu-Ghali, 1997).