Shock-induced activity changes, adrenal lipid depletion and brain weight in mice: a genetic study.

Motor activity was evaluated before and after a brief electric shock. Whereas small genetic differences in activity were apparent prior to shock, large group differences occurred following shock. C57 mice did not freeze following a shock; DBA mice showed prolonged freezing; and the F1 hybrids froze only briefly. Backcross groups revealed segregation for postshock activity. Adrenal lipid depletion, as revealed by the absence of Sudan staining in the adrenal cortex, was detected in many male mice, but no correlation with either preor postshock activity was detected. Inheritance of adrenal lipid depletion clearly was not monogenetic.