Roles of CLCA and CFTR in electrolyte re-absorption from rat saliva.
A molecular basis for Cl- re-absorption has not been well-characterized in salivary ductal cells. Previously, we found strong expression of a rat homologue proposed to be Ca2+-dependent Cl- channels (rCLCA) in the intralobular ducts of the rat submandibular gland. To address the question as to whether rCLCA and cystic fibrosis transmembrane conductance regulator (CFTR) are involved in Cl- re-absorption, we evaluated the electrolyte content of saliva from glands pre-treated with a small interfering RNA (siRNA). Retrograde injection into a given submandibular duct of an siRNA designed to knock down either rCLCA or CFTR reduced the expression of each of the proteins. rCLCA and CFTR siRNAs significantly increased Cl- concentration in the final saliva during pilocarpine stimulation. These results represent the first in vivo evidence for a physiological significance of rCLCA, along with CFTR, in transepithelial Cl- transport in the ductal system of the rat submandibular gland.
Ishibashi
K
K
Department of Functional Bioscience, Fukuoka Dental College, Japan.
Yamazaki
J
J
Okamura
K
K
Teng
Y
Y
Kitamura
K
K
Abe
K
K
D000042:Absorption; D000818:Animals; D018118:Chloride Channels / Q000235:genetics / Q000502:physiology*; D002712:Chlorides / Q000032:analysis / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000502:physiology*; D015151:Immunoblotting; D007150:Immunohistochemistry; D018721:Muscarinic Agonists / Q000494:pharmacology; D010862:Pilocarpine / Q000494:pharmacology; D011188:Potassium / Q000032:analysis; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D012463:Saliva / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D018987:Salivary Ducts / Q000187:drug effects / Q000378:metabolism; D012964:Sodium / Q000032:analysis; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism
D018118:Chloride Channels; D002712:Chlorides; C504023:Clca5 protein, rat; D018721:Muscarinic Agonists; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D010862:Pilocarpine; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D012964:Sodium; D011188:Potassium