Control of gallbladder contractions by cholecystokinin through cholecystokinin-A receptors on gallbladder interstitial cells of Cajal.
OBJECTIVE
To identify the cholecystokinin (CCK)-A receptors (CCK-AR) on the guniea pig gallbladder interstitial cells of cajal (ICC) and to study CCK-8 induced gallbladder muscle strip contractions through the CCK-AR.


METHODS
The existence of CCK-AR was examined by immunohistofluorescence on sectioned tissue and cultured cells. In vitro contractile response of guinea pig gallbladder muscle strips and the strips with ICC removed were also studied with CCK-8 receptors added.


RESULTS
In tissue sections, intensely CCKAR-immunoreactive interstitial cells were found mainly in the muscular layers. In cultured cell sections, distinctive double staining of C-kit and CCK-AR ICCs were found. When we removed the ICC of the gallbladder, CCK-8 induced muscle strip contraction dose response curve significantly shifted to the right.


CONCLUSIONS
We proved that both the existence of CCK-AR on the guinea pig gallbladder ICC and CCK evoked contraction are mediated through direct action on CCK-AR on the gallbladder ICC.
Xu
Dan
D
Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China.
Yu
Bao-Ping
BP
Luo
He-Sheng
HS
Chen
Ling-Dan
LD
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002478:Cells, Cultured; D002756:Cholagogues and Choleretics / Q000494:pharmacology*; D002766:Cholecystokinin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005704:Gallbladder / Q000187:drug effects / Q000502:physiology*; D006168:Guinea Pigs; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D043886:Receptor, Cholecystokinin A / Q000187:drug effects / Q000378:metabolism*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D002756:Cholagogues and Choleretics; D018727:Muscarinic Antagonists; D010446:Peptide Fragments; D043886:Receptor, Cholecystokinin A; D026941:Sodium Channel Blockers; C410885:cholecystokinin 8; D013779:Tetrodotoxin; D001285:Atropine; D002766:Cholecystokinin