Antinociception induced by intraperitoneal injection of gentamicin in rats and mice.
Intraperitoneal administration of gentamicin sulfate (5-800 micrograms/kg), but not gentamicin base (23-92 micrograms/kg) produced antinociception in rats and mice, as assessed by the tail-flick, carrageenan-induced articular incapacity tests, and hot-plate tests. The AD50 s in rats (tail-flick test) and mice (hot-plate test) were 11.48 and 147.9 micrograms/kg, respectively, but doses of 200-800 micrograms/kg were required to reduce the hyperalgesia induced in rats by carrageenan. In both species, bell-shaped dose-response curves were obtained, indicating that high doses of gentamicin had little or no effect. Non-effective doses of gentamicin failed to produce a significant increase in morphine antinociception in either rodent species. The possible involvement of N-type voltage-sensitive Ca2+ channels in the mechanism of antinociception induced by gentamicin is considered.
Prado
W A
WA
Department of Pharmacology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, 14049 Ribeirão Preto, SP, Brazil.
Tonussi
C R
CR
Rego
E M
EM
Corrado
A P
AP
D000818:Animals; D004357:Drug Synergism; D005839:Gentamicins / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects*; D010147:Pain Measurement; D051381:Rats; D011919:Rats, Inbred Strains; D012684:Sensory Thresholds / Q000187:drug effects
D005839:Gentamicins; D009020:Morphine