Possible prostaglandin-dopamine interactions during experimental gastric ulcer formation.
The effects of dopamine (DA) agonists and antagonists were investigated on indomethacin--and restraint stress (6 hr at RT)--induced gastric ulcer formation in rats. The DA-agonists, apomorphine and bromocryptine (both at 5 mg/kg) significantly attenuated the frequency and severity of gastric mucosal lesions in both experimental models. The DA-antagonist, haloperidol (0.05 and 1.0 mg/kg) aggravated the gastric ulcerogenesis of both indomethacin and stress, the effects with the lower dose being statistically significant. Haloperidol (0.05 mg/kg) also prevented the cytoprotective effects of apomorphine on indomethacin-ulcers. The atypical DA-antagonist, sulpiride (10 and 50 mg/kg), however, showed differential dose- and model-specific effects. Whereas, the lower dose attenuated indomethacin-ulcers, the higher dose (50 mg/kg) tended to aggravate this phenomenon. The trend of results were reversed in the restraint stress model. Indomethacin (1 mg/kg) aggravated stress-ulcers, an effect which was also appreciably neutralised by apomorphine (5 mg/kg) pretreatment. These results are discussed in light of possible prostaglandin-DA interactions during such experimental gastric pathology.
Ray
A
A
Department of Pharmacology, University College of Medical Sciences, Delhi, India.
Khanna
N
N
Sen
P
P
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001971:Bromocriptine / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology*; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D007213:Indomethacin / Q000633:toxicity*; D008297:Male; D011453:Prostaglandins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013276:Stomach Ulcer / Q000378:metabolism*; D013312:Stress, Physiological
D015259:Dopamine Agents; D018492:Dopamine Antagonists; D011453:Prostaglandins; D001971:Bromocriptine; D006220:Haloperidol; D001058:Apomorphine; D004298:Dopamine; D007213:Indomethacin