The role of adrenergic, purinergic and opiate receptors in the control of prostacyclin-induced contraction in the guinea-pig ileum.
The interactions between prostacyclin (PGI2) and adrenergic, opiate, purinergic receptor agonists and antagonists were studied in isolated segments of guinea-pig ileum by recording the changes in isometric tension. The contractile response of these preparations to PGI2 was rapid and qualitatively similar to the effect of acetylcholine. Noradrenaline (30-300 nM) reduced the effect of PGI2 (20 nM) in a concentration-dependent manner. The inhibitory action of noradrenaline on PGI2-induced contractions was prevented by the alpha-blocker phentolamine and unaffected by the beta-blocker D(--)INPEA. Morphine (10,50 nM) antagonized the response of the ileum to PGI2 and naloxone prevented this inhibition. Also N6-phenylisopropyladenosine (PIA) (10,50 nM) inhibited the effect of PGI2, which was restored when theophylline was added before PIA. The present results indicate that presynaptic alpha-adrenergic, opiate and purinergic receptor stimulation operates a negative control on the effect of PGI2 in guinea-pig ileum.
D000818:Animals; D011464:Epoprostenol / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D010660:Phenylisopropyladenosine / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000187:drug effects*; D017981:Receptors, Neurotransmitter / Q000187:drug effects*; D011957:Receptors, Opioid / Q000187:drug effects*; D011983:Receptors, Purinergic; D013806:Theophylline / Q000494:pharmacology
D011941:Receptors, Adrenergic; D017981:Receptors, Neurotransmitter; D011957:Receptors, Opioid; D011983:Receptors, Purinergic; D010660:Phenylisopropyladenosine; D009020:Morphine; D013806:Theophylline; D011464:Epoprostenol; D009638:Norepinephrine; D010646:Phentolamine