G. ChaturapanichK. SujaritC. PholpramoolMahidol University2018-09-072018-09-071999-01-01Journal of Reproduction and Fertility. Vol.117, No.2 (1999), 199-205002242512-s2.0-0032702914https://repository.li.mahidol.ac.th/handle/20.500.14594/25358This study was undertaken to investigate the effects of sulphapyridine on the transport of spermatozoa through different regions of the epididymis and on the contractility of the epididymal duct in the rat. Sperm transport was investigated by labelling testicular spermatozoa with [3H]thymidine and measuring intraluminal pressures of the epididymis by micropuncture, using a servo-nulling pressure transducer system. In control rats, the transit times of epididymal spermatozoa from the initial segment to the caput, from the caput to the proximal cauda, and from the proximal cauda to the distal cauda were 2, 6 and 3 days, respectively, giving a total transit time of 11 days. The total transit time was shortened to 8 days after treatment with sulphapyridine at a dosage of 450 mg kg-1for 38-52 days. The rate of sperm transport was most affected in the caput epididymidis. Measurements of intraluminal pressures showed that sulphapyridine had no effect on spontaneous contractions in any regions of the epididymis. However, the frequency of contraction of the corpus and cauda epididymides in response to administration of 10 μg noradrenaline kg-1in the sulphapyridine-treated rats was significantly higher (P < 0.05) than it was in the controls. Methacholine, at a dose of 20 μg kg-1, produced a smaller increase in basal pressure in the caput epididymidis of sulphapyridine-treated rats (P < 0.05) compared with controls. The results led to the conclusion that sulphapyridine increases the rate of sperm transport from the caput through the cauda epididymidis, in part, by changes in the responsiveness of the epididymis to the autonomic nervous system.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.1530/jrf.0.1170199