Polyviewed expression of the altered contractility of the guinea-pig ileum after ischemia in situ and superfusion in vitro.
This study deals with the polyviewed expression of the altered contractility of the isolated ileum of the guinea-pig after ischemia/superfusion (I/S). Intestinal ischemia was produced by clamping the superior mesenteric artery for 40, 80 or 160 min. Ischemic and non-ischemic segments taken from the same guinea-pig were mounted for tension recording in organ baths and superfused (120 min) with an oxygenated Krebs-bicarbonate solution. Data were analyzed by means of the Polyview System software, which allows detecting simultaneously several events of one response. Histopathological changes in myenteric neurons were also examined. We found that ischemia in situ followed by superfusion in vitro (reoxygenation) severely reduces the spontaneous intestine contractile activity, and significantly decreases the maximal contractile response to ACh and to electrical field stimulation (EFS), the maximal rate of tension, and the sensitivity of the tissue to EFS. In addition, these ischemic intestines respond with a long-lasting contracture when electrical stimulation was started at supramaximal voltage. Functional alterations were time dependent. Neurons exhibited features of necrosis. These results provide clear evidence of detrimental effects of I/S on intestine contractile function. Digital analysis allows quantification of additional parameters important for evaluation of functional changes after I/S and of the degree of neuroprotection.
Santiago-Mejia
J
J
Department of Pharmacology, School of Medicine, National University of Mexico, Mexico City, Mexico. rodcar@servidor.unam.mx.
Ventura-Martinez
R
R
Gomez
C
C
Parra-Gamez
L
L
Gonzales-Rios
J
J
Rodriguez
R
R
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D006168:Guinea Pigs; D017665:Hydroxyl Radical; D007082:Ileum / Q000098:blood supply* / Q000502:physiology; D007511:Ischemia / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction
D017665:Hydroxyl Radical; D000109:Acetylcholine