Effect of chronic intermittent immobilization stress on Fos-like immunoreactivity in rat brain and adrenal medulla

The present study examined the influence of short- and long-term chronic intermittent immobilization stress throughout the brain and on the adrenal medulla of intact rats using Fos-like immunoreactivity (Fos-LI) as a marker of cellular activation. The effect of adreno-medullectomy on the central nervous system (CNS) response to chronic immobilization stress was also examined. It was found that control unoperated, unstressed rats had no Fos-LI cells in the brain or in the adrenal medulla. In intact rats, neither short term (1 week) nor long term (4 weeks) chronic intermittent immobilization stress produced significant increases in Fos-LI in the CNS compared with control animals. However, marked increase in the number of Fos-LI cells was observed in the adrenal medulla of animals stressed for 4 weeks compared with control, unstressed animals or those stressed for 1 or 2 weeks. In adreno-medullectomised rats, 4 weeks, but not 1 week, chronic immobilization stress produced significant increases in numbers of Fos-LI neurons in the paraventricular hypothalamic and supraoptic nuclei and the medial amygdala compared with intact animals stressed for a similar period of time. It is concluded that long term stress produces chronic Fos-LI in the adrenal medulla and that adreno-medullectomy increases the Fos response of the PVN, supraoptic nucleus and medial amygdala to long term stress.     

Effect of levels of exercise on psychological mood states, physical fitness, and plasma beta-endorphin

Aerobic exercise which resulted in a significant improvement in cardiovascular functioning had no more effect on psychological mood states than did the placebo control of participation in nonaerobic recreational games or no exercise and sport at all (N = 430 college students). Beta-endorphin levels with the 41 depressed subjects were not a biochemical link that might explain the possible influence of physical activity on depression.     

Vulnerability of skeletal and autonomic manifestations of memory in the rat to electroconvulsive shock.

A series of experiments was performed to probe the phenomenon of sparing of memory by electroconvulsive shock (ECS) when amnesia is assessed by autonomic indices. Differential vulnerability of memory as indexed by skeletal and autonomic responses was determined to be a function of a higher threshold to disruption for autonomically indexed memories. Autonomic responses spared by ECS were found to reflect underlying memory rather than artifact produced by nonassociative factors arising from the interaction of conditioned stimulus (CS), unconditioned stimulus (US), and ECS. Furthermore, retrograde amnesia gradients of different slopes were observed with skeletal and autonomic measures. Two interpretations of these phenomena are discussed. One hypothesis suggests that individual components of a memory are consolidated at different rates, whereas the other concerns the differentail sensitivity of various measures in assessing memory.