1973 Volume 37 Issue 10 Pages 1265-1270
Shortly after the beginning of immobilization stress a remarkable elevation in the arterial pressure, a significant increase in plasma renin levels and plasma corticosterone concentrations were observed. However the changes of plasma renin levels throughout the immobilization stress did not coincided with those of plasma corticosterone concentrations and adrenocortical biosynthetic activity. There seem to be the different mechanisms to activate the renin angiotensin system and the pituitary-adrenocortical system. The changes of the EEG activity during the stress suggested that the homeostatic mechanisms mediated by the activity of the mesencephalic reticular formation and the mesencephalic central grey seemed to regulate the blood pressure. The involvement of the mesencephalic reticular formation and the mesencephalic central grey was also suggested by the stimulation experiments; that is, the mesencephalic reticular formation, the mesencephalic central grey and the posterior hypothalamic area seemed to be more effective on the release of renin than on the release of corticosterone, while the other areas in the brain such as the hippocampus, the amygdala and the anterior hypothalamic area were not so effective on the release of renin.
