Involvement of muscarinic acetylcholine receptors in chloride secretion by cultured rat epididymal epithelium.
The aim of our present study was to investigate the short-circuit current response to carbachol in cultured rat cauda epididymal epithelia and the signal transduction mechanisms involved. Carbachol added basolaterally induced a concentration-dependent increase in short-circuit current (Isc) across the epididymal epithelium consisting of a rapidly rising phase and a long term sustained response. The response was almost abolished by removing Cl(-) from the extracellular medium and blockable by pretreating the tissues with DPC, indicating a substantial contribution of Cl(-) secretion to the carbachol-induced response. The muscarinic acetylcholine receptor antagonist atropine inhibited the response, but the nicotinic acetylcholine receptors antagonist curarine had no effect, suggesting that only the muscarinic acetylcholine receptors mediated the secretory response of the basolateral side of rat cauda epididymal epithelium to carbachol. Addition of carbachol to the apical side of the tissue was found not to elicit an Isc response. These results suggested that muscarinic receptors are present in the basolateral side of rat cauda epididymal epithelium. Activation of these receptors by acetylcholine released from the nerve endings regulates epididymal transepithelial Cl(-) secretion. Cholinergic stimulation therefore contributes to the formation of luminal fluid microenvironment.
Du
Jian-Yang
JY
School of Life Science, Sun Yat-Sen University, 135 Xingang West Road, Guangzhou 510275, PR China.
Zuo
Wu-Lin
WL
Chen
Min-Hui
MH
Xiang
Hui
H
Zhou
Wen-Liang
WL
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D004822:Epididymis / Q000187:drug effects / Q000378:metabolism*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011976:Receptors, Muscarinic / Q000378:metabolism*; D015398:Signal Transduction
D018118:Chloride Channels; D002712:Chlorides; D018721:Muscarinic Agonists; D011976:Receptors, Muscarinic; D002217:Carbachol