Abstract
Summary and Conclusions
1. A method is described for measuring stimulation produced by analeptics, which consists of suspending white rats or other small animals in small cages from wire springs and summating the amount of movement by connecting the springs to Harvard work adders. The activities resulting over periods of hours, are recorded by electrical contacts on the work adders through signal magnets writing on a kymograph drum. The apparatus is kept in a lighted constant temperature chamber between 27 and 29° C as conditions for minimum activity. The amounts of activity shown by the animals after injections of normal saline solution are designated as control levels of activity, and subtracted from those observed during the action of a drug to give the net stimulation produced by the agent in question.
2. Metrazol, in doses from 10 to 40 mg per kilo, produced no increase in general activity except during convulsions resulting from doses of 40 mg. Picrotoxin, in doses from 0.1 to 1.6 mg per kilo also produced no increase in activity, except after doses of 1.6 mg, when the animals were in generalized convulsions. Therefore, these two agents showed no evidence of stimulating the higher levels of the nervous system, particularly the areas for purposeful coordinated movement.
3. Coramine, in doses of 20 mg per kilo, produced just perceptible degrees of increase of coordinated and purposeful activity, and with 40, 80, and 160 mg doses these changes were so large as to be unmistakable. The highest dose caused generalized convulsions in some animals. The actions of 160 mg persisted for about 7 hours, whereas those of 40 and 80 mg lasted 2 1/2 and 4 hours, respectively.
4. Caffeine sodiobenzoate in doses of 10 mg per kilo, produced threshold increases in activity similar to that of coramine.
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