Role of gap junctions in fluid secretion of lacrimal glands.
In glands such as the liver and pancreas, gap junctions containing connexin 26 and 32 (Cx26 and Cx32, respectively) couple the secretory cells. Uncoupling these junctions compromises the secretory function of these glands. Lacrimal glands also contain extensive arrays of gap junctions consisting of Cx26 and Cx32. We wanted to determine the role of these junctions in fluid secretion. In Cx32-deficient mice, immunocytochemistry showed that, in the male lacrimal gland, the remaining Cx26 was found evenly distributed in the membrane whereas there was little in the membranes of female glands. Western blot analysis of Cx26 showed that female Cx32-deficient mice expressed Cx26. Patch-clamp analyses of acinar cell coupling showed that the cell pairs from male glands were coupled whereas those from female glands were not. Stimulated fluid production by the glands from Cx32-deficient mice was abnormally low in female glands compared with controls at low topical doses of carbachol. The protein secretory response to different doses of carbachol was the same in all animals. These data suggest that gap junctions are essential for optimal fluid secretion in lacrimal glands.
Walcott
Benjamin
B
Department of Neurobiology and Behavior, State University of New York, Stony Brook, NY 11794, USA. bwalcott@ms.cc.sunysb.edu
Moore
Leon C
LC
Birzgalis
Aija
A
Claros
Nidia
N
Valiunas
Virginijus
V
Ott
Thomas
T
Willecke
Klaus
K
Brink
Peter R
PR
D000704:Analysis of Variance; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002478:Cells, Cultured; D018679:Cholinergic Agonists / Q000494:pharmacology; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D017629:Gap Junctions / Q000378:metabolism*; D007765:Lacrimal Apparatus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D018408:Patch-Clamp Techniques; D013666:Tears / Q000378:metabolism*; D000097002:Gap Junction beta-1 Protein
D002217:Carbachol; D018679:Cholinergic Agonists; D000072259:Connexin 26; D017630:Connexins; D000097002:Gap Junction beta-1 Protein; C000607043:Gjb2 protein, mouse