Lai K B, Fu W O, Ko W H, Chan H C, Wong P Y
Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin, New Territories.
Am J Physiol. 1994 Aug;267(2 Pt 1):C607-16. doi: 10.1152/ajpcell.1994.267.2.C607.
Primary cultured rat efferent ductal epithelia and cauda epididymal epithelial were mounted in Ussing chambers to study the effect of arginine vasopressin (AVP) on chloride secretion in the male excurrent duct. The regional differences in the signal transduction pathways involved were also investigated. In both the efferent duct and the cauda epididymidis, basolateral addition of AVP resulted in a dose-dependent increase in the short-circuit current (Isc), which was mediated via V1 receptor. Replacement of ambient Cl- with gluconate or pretreatment of a Cl- channel blocker, diphenylamine-2-carboxylate (apical, 1 mM), completely abolished the response, whereas addition of amiloride had no effect on the Isc. Pretreating the epithelia of the efferent duct with indomethacin (apical, 5 microM) or forskolin (basolateral, 1 microM), but not thapsigargin (apical, 1 microM) or trifluoperazine (apical, 20 microM), significantly inhibited the AVP response (P < 0.001). By comparison, pretreating the epithelia of the cauda epididymidis with any of the four agents significantly reduced the AVP-evoked response. These results suggested that the stimulation of chloride secretion by AVP in the efferent duct and the cauda epididymidis is mediated by prostaglandin synthesis and involves adenosine 3',5'-cyclic monophosphate (cAMP) as a second messenger. In the cauda epididymidis, calcium, in addition to cAMP, may play a role in mediating the AVP-induced response.
将原代培养的大鼠输出小管上皮细胞和附睾尾上皮细胞置于尤斯灌流小室中，以研究精氨酸加压素（AVP）对雄性输出管中氯离子分泌的影响。同时还研究了所涉及信号转导途径的区域差异。在输出小管和附睾尾中，从基底外侧加入AVP均导致短路电流（Isc）呈剂量依赖性增加，这是通过V1受体介导的。用葡萄糖酸盐替代细胞外氯离子或用氯离子通道阻滞剂二苯胺 - 2 - 羧酸盐（顶端，1 mM）预处理，可完全消除该反应，而加入阿米洛利对Isc无影响。用吲哚美辛（顶端, 5 μM）或福斯可林（基底外侧, 1 μM）预处理输出小管上皮细胞，但用毒胡萝卜素（顶端, 1 μM）或三氟拉嗪（顶端, 20 μM）预处理则不会，可显著抑制AVP反应（P < 0.001）。相比之下，用这四种药物中的任何一种预处理附睾尾上皮细胞，均可显著降低AVP诱发的反应。这些结果表明AVP对输出小管和附睾尾中氯离子分泌的刺激是由前列腺素合成介导的，并且涉及腺苷3',5'-环磷酸（cAMP）作为第二信使。在附睾尾中，除了cAMP外，钙可能在介导AVP诱导的反应中起作用。
