Pertussis toxin blocks the action of morphine, norepinephrine and clonidine on isolated guinea-pig ileum.
Administration of pertussis toxin (60 micrograms/kg i.p.) to guinea-pigs blocked the ability of morphine, norepinephrine and clonidine to inhibit electrically stimulated contractions in the isolated ileum. The toxin reached its maximum effect 6 days after its administration. The effect of the toxin was reversible; a slow but full recovery of the response to morphine was observed in ilea from guinea-pigs treated with toxin 18 days before the experiment. It is suggested, based on the known action of pertussis toxin, that inhibition of adenylate cyclase through Ni (guanine-nucleotide regulatory protein) is involved in the acute action of morphine, norepinephrine and clonidine in the motoneurons of the myenteric plexus of the ileum.
D037361:Adenylate Cyclase Toxin; D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology*; D003000:Clonidine / Q000037:antagonists & inhibitors*; D004558:Electric Stimulation; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors*; D009046:Motor Neurons / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000037:antagonists & inhibitors*; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella
D037361:Adenylate Cyclase Toxin; D001427:Bacterial Toxins; D010566:Virulence Factors, Bordetella; D009020:Morphine; D037342:Pertussis Toxin; D003000:Clonidine; D009638:Norepinephrine