Esophageal and gastric smooth muscle activity after carbon dioxide pneumoperitoneum.
BACKGROUND
The metabolic changes associated with carbon dioxide (CO(2)) pneumoperitoneum include metabolic acidosis and lowered intra-abdominal pH values. An experimental study was performed to evaluate the effect of CO(2) pneumoperitoneum on esophageal and gastric smooth muscle sensitivity in response to several agonists.


METHODS
Wistar albino rats, weighing 200-250 g, were allocated into three groups. After anesthetization with ketamine hydrochloride and xylazine, abdominal esophagus, gastroesophageal junction, and gastric fundus were removed via median laparotomy in the control group. In the oxygen (O(2)) group, a 16G catheter was inserted into the abdomen above the umbilicus and insufflated with 95% O(2) and 5% CO(2) with a pressure of 10 mm Hg. In the CO(2) group, CO(2) was insufflated at the same pressure within the same time and the tissues were removed at the end of a 60 min period of pneumoperitoneum. Abdominal esophageal segment (n:6), gastroesophageal junction (n:6) and gastric fundus (n:12) were suspended under 0.5 to 2 g resting tension in Tyrode solution in organ baths. Contraction responses were obtained by carbachol and serotonin and relaxation responses were evaluated by isoproterenol in each group. All the responses were compared by nonparametric Kruskal Wallis test.


RESULTS
Carbachol and serotonin induced contractile responses of abdominal segments, gastroesophageal junction, and gastric fundus showed no difference between the control, O(2), and CO(2) groups (P > 0.05). Isoproterenol relaxation responses of the three groups were also not statistically different from each other (P > 0.05).


CONCLUSIONS
CO(2) pneumoperitoneum of 60 min has no influence on esophageal and gastric smooth muscle responses to different agonists in rats.
Soyer
Tutku
T
Department of Pediatric Surgery, Kirikkale University, Faculty of Medicine Kirikkale, Turkey. tutku@sanalofis.net
Aktuna
Zuhal
Z
Reşat Aydos
Tolga
T
Osmanoğlu
Gökhan
G
Korkut
Oğuzhan
O
Akman
Hülya
H
Cakmak
Murat
M
D000005:Abdomen / Q000503:physiopathology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002245:Carbon Dioxide / Q000494:pharmacology; D004947:Esophagus / Q000187:drug effects / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology; D007813:Laparotomy / Q000379:methods; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000503:physiopathology*; D011027:Pneumoperitoneum / Q000139:chemically induced / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D013270:Stomach / Q000187:drug effects / Q000503:physiopathology*
D002245:Carbon Dioxide; D012701:Serotonin; D002217:Carbachol; D007545:Isoproterenol