Effect of repeated immobilization stress on central and peripheral adrenoceptors in rats.

Repeated forced immobilization stress (40 times for 2.5 h daily) reduced the number of beta-receptors in the heart, hypothalamus and brain stem, but not in the spleen of rats. Repeated immobilization stress has also been found to decrease the number of alpha1-receptors in the heart and increase the number of alpha2-receptors in the spleen and brain stem, as compared to control unstressed rats. The number of heart alpha1-, spleen and brain stem alpha2-receptors was still decreased or increased, respectively, 24 h after the 39th immobilization stress. However, at the same time the number of beta-receptors in the heart and brain stem returned to the control levels. We concluded, that the changes in the number of rat adrenoceptors in the heart, hypothalamus and brain stem correlate with peripheral catecholamines released during repeated immobilization stress.