Sleeping Time Responses of Mice—Random Bred, Inbred and F1 Hybrids—to Pentobarbitone Sodium

Abstract

Abstract The sensitivity and the precision of the sleeping time responses to pentobarbitone sodium in 10 per cent ethanol in mice varies with the strain of mouse. In any one strain sleeping time response in animals dosed by weight with pentobarbitone sodium is related to the weight of the animals. As mice aged, the sleeping time for all strains differed between the sexes, the males sleeping longer than the females. If the same mice were reinjected with pentobarbitone sodium the ageing effect was accelerated. It has been confirmed that the responses of F1 hybrids must be determined experimentally, and may resemble that of either parent, or fall between or outside those of their parents. In choosing animals for the estimation of pharmacological responses, therefore, their strain, weight, age and sex are each of importance, and should be as controlled as their environment before and during tests