1985 Volume 10 Issue 3 Pages 195-201
The effects of methamphetamine and morphine on the vertical (VMA) and horizontal motor activity (HMA) in male mice of the ddY strain, weighing 24-28g, were investigated, using an optical movement counter developed by Itoh and collaborators. All measurments were taken at 10 min. intervals during the 180 min. period following administration of the drugs. The results are summarized as follows.
When administering methamphetamine;
1) With 0.1mg/kg, s.c., the VMA and HMA slightly decreased.
2) With 1mg/kg, s.c., the VMA and HMA increased.
3) With 10mg/kg, s.c., the VMA and HMA markedly increased, showing biphasic patterns that quantatively differ from the changes found in a low dose (1mg/kg)-induced VMA and HMA.
When administering morphine;
1) With any dose used in this study, the VMA decreased.
2) With a low dose (2mg/kg), the HMA decreased, but with a high dose (10mg/kg or more) the HMA increased dosedependently.
These results show that methamphetamine and morphine exert different effects on the VMA and HMA in mice, depending upon the dosage.
