Phenylpyrazolone derivatives inhibit gastric emptying in rats by a capsaicin-sensitive afferent pathway.
Dipyrone (Dp), 4-aminoantipyrine (AA) and antipyrine (At) administered iv and Dp administered icv delay gastric emptying (GE) in rats. The participation of capsaicin (Cps)-sensitive afferent fibers in this phenomenon was evaluated. Male Wistar rats were pretreated sc with Cps (50 mg/kg) or vehicle between the first and second day of life and both groups were submitted to the eye-wiping test. GE was determined in these animals at the age of 8/9 weeks (weight: 200-300 g). Ten minutes before the study, the animals of both groups were treated iv with Dp, AA or At (240 micromol/kg), or saline; or treated icv with Dp (4 micromol/animal) or saline. GE was determined 10 min after treatment by measuring % gastric retention (GR) of saline labeled with phenol red 10 min after orogastric administration. Percent GR (mean +/- SEM, N = 8) in animals pretreated with Cps and treated with Dp, AA or At (35.8 +/- 3.2, 35.4 +/- 2.2, and 35.6 +/- 2%, respectively) did not differ from the GR of saline-treated animals pretreated with vehicle (36.8 +/- 2.8%) and was significantly lower than in animals pretreated with vehicle and treated with the drugs (52.1 +/- 2.8, 66.2 +/- 4, and 55.8 +/- 3%, respectively). The effect of icv administration of Dp (N = 6) was not modified by pretreatment with Cps (63.3 +/- 5.7%) compared to Dp-treated animals pretreated with vehicle (62.3 +/- 2.4%). The results suggest the participation of capsaicin-sensitive afferent fibers in the delayed GE induced by iv administration of Dp, AA and At, but not of icv Dp.
Departamento de Pediatria, Universidade Estadual de Campinas, Campinas, SP, Brasil.
A M
AM
Vinagre
E F
EF
Collares
D000344:Afferent Pathways / Q000187:drug effects*; D000675:Ampyrone / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D000983:Antipyrine / Q000008:administration & dosage / Q000494:pharmacology*; D002211:Capsaicin; D004177:Dipyrone / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005746:Gastric Emptying / Q000187:drug effects; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000675:Ampyrone; D004177:Dipyrone; D002211:Capsaicin; D000983:Antipyrine