Abstract
Effect of NAN-190, a selective 5-HT
1A receptor antagonist, on methamphetamine-induced locomotor activity, anorexia, analgesia, and hyperthermia was investigated in male mice. Methamphetamine (1.5
mg/kg, i.p) produced a significant increase in locomotor activity, which was significantly antagonized by NAN-190 at a dose of 4
mg/kg, i.p. NAN-190 did not alter the antinociceptive activity of mice when it was administered alone. Methamphetamine (2
mg/kg, i.p) produced a significant decrease in food intake of mice, which were deprived of food during the previous 24
h. This anorectic activity of methamphetamine was significantly antagonized by NAN-190 at a dose of 2
mg/kg, i.p. NAN-190 did not alter the food intake of mice when it was administered alone. Methamphetamine (2
mg/kg, i.p) also produced a significant increase in body temperature of mice, which was significantly antagonized by NAN-190 at a dose of 0.5
mg/kg, i.p. NAN-190 did not alter the body temperature of mice when it was administered alone. In the writhing test, methamphetamine (1
mg/kg, i.p) produced a significant antinociceptive effect in mice. This was significantly antagonized by NAN-190 at a dose of 1
mg/kg, i.p. NAN-190 did not alter the antinociceptive activity of mice when it was administered alone. The results of the present study indicate a possible role for serotonergic mechanisms, in addition to the catecholaminergic systems, in the above-studied activities of methamphetamine in mice. This role is possibly mediated through direct stimulation of the 5-HT
1A receptor subtype. All of the above-studied activities of methamphetamine were antagonized by NAN-190, which may indicate that NAN-190 is a possible antagonist for methamphetamine.