Effects of mu and kappa opioid receptor agonists and antagonists on contraction of isolated colon strips of rats with cathartic colon.
OBJECTIVE
To study the effects of mu and kappa opioid receptor agonists and antagonists on the isolated colon strips of rats with cathartic colon.


METHODS
Cathartic colon model was established by feeding rats with contact laxatives, and effects of mu and kappa opioid receptor agonists and antagonists on electricity-stimulated contraction of isolated colon strips of rats with cathartic colon were observed.


RESULTS
Compared with control group, exogenous mu and kappa agonists inhibited significantly electricity-stimulated contraction of strips of cathartic colon (8.50+/-0.89 mm, 6.24+/-0.91 mm, 3.35+/-0.6 mm vs 11.40+/-0.21 mm P<0.01; 8.98+/-0.69 mm, 6.89+/-0.71 mm, 4.43+/-0.99 mm vs 11.40+/-0.21 mm, P<0.01). In contrast, the exogenous mu antagonist significantly enhanced electricity-stimulated contraction of isolated colon strips (13.18+/-0.93 mm, 15.87+/-0.98 mm, 19.46+/-1.79 mm vs 11.40+/-0.21 mm, P<0.01), but kappa antagonist had no effect on the isolated colon strips of rats with cathartic colon.


CONCLUSIONS
Mu and kappa opioid receptors are involved in the regulation of colon motility of rats with cathartic colon.
Liu
Bao-Hua
BH
Department of General Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China. lbh57268@163.com
Mo
Ping
P
Zhang
Sheng-Ben
SB
D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D002400:Cathartics / Q000494:pharmacology; D003106:Colon / Q000187:drug effects / Q000502:physiology; D003109:Colonic Diseases, Functional / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D003248:Constipation / Q000188:drug therapy*; D004558:Electric Stimulation; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / Q000494:pharmacology; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017473:Receptors, Opioid, kappa / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000378:metabolism
D000701:Analgesics, Opioid; D002400:Cathartics; D009292:Narcotic Antagonists; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009270:Naloxone