Long-lasting antinociceptive effect of RC-160, a somatostatin analog, in mice and rats.
The effect of RC-160 (D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2) was studied in mice by means of the hot plate test and in rats with the tail flick test. In mice, 512 micrograms/kg (s.c.) induced an antinociceptive effect maximal (+88 +/- 17%) at the 6th hour after injection but still significant at the 24th hour; 16 micrograms/kg (s.c.) was active for 3 h; 64, 256 and 1024 micrograms/kg were active 30 min, 3 and 24 h after injection. The effects of these last three doses were not different. The antinociceptive action was as high at 24 h as at 3 h (e.g. for 512 micrograms/kg, 44 +/- 9% and 51 +/- 12%, respectively); 48 h after injection the scores of the treated groups were not different from the score for saline treatment in the tail flick test, 512 micrograms/kg induced a significant antinociceptive effect for 12 h (maximal at the 3rd hour: +60%). No behavioral changes, and particularly no motor activity modifications were observed.
Laboratoire de Pharmacologie Médicale, INSERM U195, Faculté de Médecine, Clermont-Ferrand, France.
A
A
Eschalier
O
O
Aumaître
D
D
Ardid
J
J
Fialip
P
P
Duchêne-Marullaz
D000595:Amino Acid Sequence; D000700:Analgesics; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000494:pharmacology
D000700:Analgesics; C051458:vapreotide; D013004:Somatostatin