1961 年 81 巻 2 号 p. 215-221
The analgesic activity of some sympathomimetic amines and related substances was tested by means of the hot-plate method and the pressure pain method, which were reported in the previous papers. Motor activity of mice on the hot plate was recorded and compared at the same time. The mice, given 1mg./kg. of methamphetamine subcutaneously, became sensitive to heat pain and the secondary reaction time to jump out of the hot plate was reduced. Although larger doses of methamphetamine increased the motor activity on the hot plate, it prolonged the secondary reaction time, which was considered to be the analgesic effect of the drug.
In general, the analgesic activity of sympathomimetics increased along with their stimulatory action, which is clearly shown in the comparison between d- and l-methamphetamine. Adrenaline and ephedrine exhibited a slight analgesic activity. Central stimulants, such as methyl phenidate and caffeine, also showed some analgesic action.
The analgesic action of morphine (2mg./kg.) and methamphetamine (5mg./kg.) was significantly potentiated and the excitatory action of methamphetamine was diminished on combined use.