Inhibition of gastric motor activity by 16,16-dimethyl prostaglandin E2. A possible explanation of cytoprotection.
Effects of 16-dimethyl prostaglandin E2 (16-dmPGE2) and necrotizing agents on gastric motility and gastric mucosa were studied in conscious rats. Gastric motility was determined using a miniature balloon positioned in the glandular part of the stomach, which was connected to a pressure transducer and polygraph. Necrotizing agents, such as absolute ethanol, 0.6 N HCl, 0.2 N NaOH, or 4 M NaCl, were instilled into the stomach through a small fistula prepared in the forestomach. One milliliter of these agents produced streak lesions in the glandular part of the stomach within 1 hr, which were preceded by violent gastric contraction in every case. An intragastric administration of 16-dmPGE2 (0.3-3 micrograms/kg) by itself increased a tonus of the gastric wall but dose-dependently lessened the number and the amplitude of contractions. In those rats treated with 16-dmPGE2 (3 micrograms/kg), necrotizing agents failed to enhance the motility or to induce streak lesions. Pretreatment with 1 M NaCl as a mild irritant also inhibited gastric motility and lesion formation, but those actions were significantly antagonized by indomethacin (5 mg/kg). These results indicate that necrotizing agents induce a violent gastric contraction, followed by development of lesions in the stomach, and that the inhibition of gastric hypercontraction may be involved in a cytoprotective action of a prostaglandin against those induced gastric lesions in rats.
D015064:16,16-Dimethylprostaglandin E2 / Q000494:pharmacology*; D000818:Animals; D004347:Drug Interactions; D000431:Ethanol / Q000378:metabolism; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006851:Hydrochloric Acid / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009336:Necrosis / Q000139:chemically induced; D011459:Prostaglandins E, Synthetic / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride / Q000494:pharmacology; D012972:Sodium Hydroxide / Q000378:metabolism; D014160:Transducers, Pressure
D011459:Prostaglandins E, Synthetic; D000431:Ethanol; D012965:Sodium Chloride; D012972:Sodium Hydroxide; D015064:16,16-Dimethylprostaglandin E2; D006851:Hydrochloric Acid; D007213:Indomethacin