Dilated bile canaliculi and attenuated decrease of nerve-dependent bile secretion in connexin32-deficient mouse liver.
Gap junction channels in the rodent liver are composed of connexin26 (Cx26) and connexin32 (Cx32) proteins. Gap junctional intercellular communication in the mouse liver enhances the effects of hormonal or sympathetic stimulation of glucose release from glycogen stores. To determine whether contraction of bile canaliculi and bile secretion are dependent on the function of gap junction channels, we compared wild-type and connexin32-deficient mice. Confocal laser scanning microscopy of the wild-type mouse liver confirmed the close association of connexin26 and -32 proteins with the zona occludens-1 protein and actin filaments of the bile canaliculi. The decrease of bile flow after electrical stimulation of sympathetic nerves in the perfused liver was attenuated in the Cx32-deficient liver compared with wild-type controls. The amount of secreted bile, however, was similar in wild-type and Cx32-deficient livers. Furthermore, Cx32-deficient mice exhibited dilated bile canaliculi, suggesting that the contraction of bile canaliculi could be impaired in these animals.
Temme
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Institut für Immunologie, Medizinische Fakultät Carl Gustav Carus, TU Dresden, Germany.
Stümpel
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F
Söhl
G
G
Rieber
E P
EP
Jungermann
K
K
Willecke
K
K
Ott
T
T
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001646:Bile / Q000378:metabolism* / Q000502:physiology; D001648:Bile Canaliculi / Q000473:pathology*; D000072259:Connexin 26; D017630:Connexins / Q000032:analysis / Q000172:deficiency* / Q000502:physiology; D004108:Dilatation, Pathologic; D004558:Electric Stimulation; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D017629:Gap Junctions / Q000737:chemistry / Q000502:physiology; D008099:Liver / Q000294:innervation / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D051379:Mice; D018613:Microscopy, Confocal; D013564:Sympathetic Nervous System / Q000503:physiopathology; D000097002:Gap Junction beta-1 Protein
D000410:Alanine Transaminase; D001219:Aspartate Aminotransferases; D000072259:Connexin 26; D017630:Connexins; D005456:Fluorescent Dyes; D000097002:Gap Junction beta-1 Protein