Effects of mexiletine on formalin-induced nociceptive responses in mice.
We investigated the effect of mexiletine on the formalin-induced nociceptive response and its modulation by diabetes. We also investigated the effects of mexiletine on intrathecally-administered substance P- and somatostatin-induced nociceptive responses in both non-diabetic and diabetic mice. Intraperitoneal injection of mexiletine (30 mg/kg) significantly reduced the duration of the formalin-induced nociceptive response in both non-diabetic and diabetic mice. When mexiletine (30 mg/kg, i.p.) was injected 30 min before injection of substance P (SP), it significantly inhibited SP-induced nociceptive responses in both non-diabetic and diabetic mice. Furthermore, mexiletine also significantly inhibited the intensity of somatostatin (SST)-induced antinociceptive effect of mexiletine in diabetic mice involves the inhibition of SP- and SST-mediated nociceptive transmission in the spinal cord.
Kamei
J
J
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Hitosugi
H
H
Kasuya
Y
Y
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology; D005557:Formaldehyde; D007274:Injections, Intraperitoneal; D007278:Injections, Spinal; D008297:Male; D008801:Mexiletine / Q000494:pharmacology*; D051379:Mice; D008813:Mice, Inbred ICR; D009619:Nociceptors / Q000187:drug effects; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D013004:Somatostatin / Q000008:administration & dosage / Q000037:antagonists & inhibitors; D013311:Streptozocin; D013373:Substance P / Q000008:administration & dosage / Q000037:antagonists & inhibitors
D005557:Formaldehyde; D008801:Mexiletine; D013373:Substance P; D013004:Somatostatin; D013311:Streptozocin