[Resistance factor in emotional stress in the brain of rats]

The authors review the results of extraction from the brain of emotional stress-resistant donor rats of fractions containing "factor" that causes the increased resistance to stress in recipient rats predisposed to stress. Brain homogenates of donor rats were subjected to thermal treatment, gel filtration on Sephadex G-15 and lyophilization. The fractions extracted are low-molecular weight, thermostable, resistant to pronase hydrolysis and significantly (P less than 0.05) increase the resistance of recipient rats to stress.