Physiological and biochemical concomitants of restraint stress in rats

Restraint stress of 30 min increases plasma CS and lowers hypothalamic NE. Restraints of longer durations are associated with an attenuation of these changes. Daily repetitive restraint enhances the CS response on the second day and progressively diminishes it on subsequent days. Whole brain NE increases on the first day and decreases on Day 2 to 5. The CS response to acute restraint is similar in 5 different normotensive rat strains, but is enhanced in the genetically hypertensive SH rat, its normotensive backbreed WKY, and the DOCA hypertensive Sprague-Dawley rat. Comparison with other stressors (electric foot shock and novel environment) indicate that the responses to restraint are different at least in time course, if not qualitatively.