Effect of peritonitis on gallbladder smooth muscle contractility in guinea pigs.
BACKGROUND
The mechanisms involved in the impaired gallbladder contractile response in peritonitis are unknown. The aim of this study was to determine the effect of peritonitis on the contraction and relaxation responses to different agonists in gallbladder smooth muscle in guinea pig.


METHODS
Peritonitis was induced by cecal ligation and puncture (CLP) in 10 guinea pigs. Another group of 10 guinea pigs underwent a sham operation and acted as controls. Twenty-four hours after the operation, the guinea pigs were killed, and gallbladder strips were placed in organ bath. The contraction responses to KCl, carbachol, and histamine, and relaxation responses to cyclooxygenase inhibitors (indomethacin, nimesulide, and DFU) on KCl-induced contractions were recorded.


RESULTS
There was no significant difference between the contractile responsiveness to KCl, but maximum contractile responses (E(max)) to carbachol and histamine were significantly reduced. Indomethacin, nimesulide, and DFU concentration dependently inhibited on KCl-induced contractions of gallbladder smooth muscle. E(max) values of indomethacin, nimesulide, and DFU were significantly reduced in the peritonitis group compared with controls (P < 0.05). The inhibitor effects of nimesulide and DFU were considerably similar, but inhibitor effect of indomethacin was significantly less than that measured for nimesulide and DFU in both control and peritonitis groups (P < 0.05).


CONCLUSIONS
The contraction responses to carbachol and histamine and relaxation responses to COX inhibitors on gallbladder smooth muscle are significantly decreased by peritonitis. Although the mechanism of the decrease in contraction and relaxation responses in CLP-induced peritonitis is completely unknown, we speculate that impaired smooth muscle responses may be related to an alteration in the regulation of receptor/postreceptor excitation-response coupling and/or through changes on Ca(2+) influx.
Kaya
Tijen Temiz
TT
Department of Pharmacology, Faculty of Medicine, Cumhuriyet University, 58030 Sivas, Turkey.
Koyluoglu
Gokhan
G
Karadas
Baris
B
Yildiz
Turan
T
Bagcivan
Ihsan
I
Ceran
Canan
C
Gökgöz
Sehsuvar
S
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002432:Cecum; D018679:Cholinergic Agonists / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D005704:Gallbladder / Q000503:physiopathology*; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D008026:Ligation; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000503:physiopathology*; D010538:Peritonitis / Q000209:etiology / Q000503:physiopathology*; D011677:Punctures
D018679:Cholinergic Agonists; D016861:Cyclooxygenase Inhibitors; D006632:Histamine; D002217:Carbachol