Effect of sumatriptan in different models of pain in rats.
The effect of sumatriptan in two standard algesimetric tests and in a model of cephalalgia was evaluated in rats. The pain threshold was measured by the hot-plate and the writhing tests; cephalalgia was produced by injecting bradykinin (10 microg in a volume of 10 microl) into a common carotid artery. Sumatriptan was subcutaneously (s.c.) injected at the doses of 4, 8, 24 or 42 mg/kg; morphine (5 or 10 mg/kg s.c.) and indomethacin (5 or 10 mg/kg s.c) were used as standard analgesic drugs. Sumatriptan had no analgesic activity either in the hot-plate test or in the writhing test. On the other hand, at 24 and 42 mg/kg it dose-dependently reduced the response to the intracarotid injection of bradykinin (vocalization and tachypnea), this effect being prevented by the 5-HT(1B) receptor antagonist, isamoltane. The 5-HT(1D) receptor antagonist BRL15572 prevented the effect of sumatriptan on bradykinin-induced tachypnea, but not the effect of sumatriptan on bradykinin-induced vocalization. These data demonstrate that sumatriptan is significantly effective in a reliable animal model of cephalalgia, while having no systemic analgesic activity.
Ottani
Alessandra
A
Department of Biomedical Sciences, University of Modena and Reggio Emilia, Section of Pharmacology, Via G. Campi 287, 41100 Modena, Italy. alessandraottani@yahoo.it
Ferraris
Eleonora
E
Giuliani
Daniela
D
Mioni
Chiara
C
Bertolini
Alfio
A
Sternieri
Emilio
E
Ferrari
Anna
A
D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D008297:Male; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D018170:Sumatriptan / Q000494:pharmacology*
D018170:Sumatriptan