Inflammatory mediators involved in the nociceptive and oedematogenic responses induced by Tityus serrulatus scorpion venom injected into rat paws.
The present study investigated the role of kinins, prostaglandins (PGs) and nitric oxide (NO) in mechanical hypernociception, spontaneous nociception and paw oedema after intraplantar (ipl) injection of Tityus serrulatus venom (Tsv) in male Wistar rats. Tsv was ipl-injected in doses of 0.01-10microg/paw. Pre-treatment (30min prior) with DALBK (100nmol/paw) and icatibant (10nmol/paw), B1 and B2 selective kinin receptor antagonists, L-NAME (50mg/kg, i.p., a non-selective nitric oxide synthase inhibitor) or celecoxib, selective COX-2 inhibitor, was given 1h prior per os (5mg/kg, p.o.), significantly reduced the hypernociceptive response (Von Frey method), the spontaneous nociception (determined by counting the number of flinches) and paw oedema (plethysmometer method) induced by Tsv at doses of 1.0 and 10microg/paw for both nociceptive and oedematogenic responses, respectively. Nevertheless, indomethacin (5mg/kg, i.p., 30min prior) was ineffective in altering all of these events. The results of the present study show that Tsv, injected ipl into the rat paw, causes a dose-dependent paw oedema, mechanical hypernociception and flinches (a characteristic biphasic response) in which kinins and NO are substantially involved. Although celecoxib was effective against the oedema and pain caused by Tsv, COX-2 does not seem to be involved in the inflammatory response caused by Tsv.
Departamento de Física e Quimica, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/n, 14040-903, Ribeirão Preto, São Paulo, Brasil.
Andréa C
AC
Pessini
Alexandre
A
Kanashiro
David do C
Ddo C
Malvar
Renes R
RR
Machado
Denis M
DM
Soares
Maria J
MJ
Figueiredo
Evanguedes
E
Kalapothakis
Glória E P
GE
Souza
D000818:Animals; D004487:Edema / Q000139:chemically induced* / Q000378:metabolism; D015777:Eicosanoids / Q000502:physiology; D007267:Injections; D007705:Kinins / Q000502:physiology*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D010146:Pain / Q000139:chemically induced* / Q000378:metabolism; D011453:Prostaglandins / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012604:Scorpion Venoms / Q000008:administration & dosage / Q000633:toxicity*; D013997:Time Factors
D015777:Eicosanoids; D007705:Kinins; D011453:Prostaglandins; D012604:Scorpion Venoms; D009569:Nitric Oxide