Antinociceptive and anti-inflammatory activities of nicotinamide and its isomers in different experimental models

Abstract

Although there is evidence for the anti-inflammatory activity of nicotinamide, there is no evaluation of its effects in models of nociceptive and inflammatory pain. In addition, there is no information about the potential anti-inflammatory and antinociceptive activities of the nicotinamide isomers, picolinamide and isonicotinamide. Per os (p.o.) administration of nicotinamide (1000mg/kg, −1h) inhibited the first and second phases of the nociceptive response induced by formalin in mice. In the model of nociceptive pain, exposure of mice to a hot-plate (50°C), nicotinamide (1000mg/kg, −1h) also presented antinociceptive activity. Nicotinamide (500mg/kg, −1 and 3h) also inhibited the mechanical allodynia induced by carrageenan in rats, a model of inflammatory pain. In addition to inhibiting the nociceptive response, nicotinamide (500 or 1000mg/kg, −1 and 3h) inhibited the paw edema induced by carrageenan in mice and rats. P.o. administration of picolinamide (125mg/kg, −1h) and isonicotinamide (500 or 1000mg/kg, −1h) inhibited the second phase of the nociceptive response induced by formalin in mice. The paw edema induced by carrageenan in mice was also inhibited by isonicotinamide (500 or 1000mg/kg, −1h) and picolinamide (125mg/kg, −1h and 3h). The results represent the first demonstration of the activity of nicotinamide and its isomers in models of nociceptive and inflammatory pain and provide support to their anti-inflammatory activity. The demonstration of new activities for nicotinamide is important as it may contribute to expand its use in the treatment of other pathological conditions.