The effects of short-term isolation on systolic blood pressure and heart rate in rats.

The effect of short-term isolation on the systolic blood pressure and heart rate of rats has been studied. Five days continuous isolation in glass metabolic cages caused systolic arterial hypertension in all animals. Isolation in standard cages for this time period caused hypertension, but only in 55% of the animals. Both forms of isolation caused an initial tachycardia. Handling and contact with other animals for 1 hr daily prevented the development of hypertension in some animals but did not alter the blood pressure once the hypertension had developed. Group-housing of animals after a 3 week period of isolation restored blood pressure to control levels within 24 hr. It is possible that stress imposed by isolation activated the sympatho-adrenal system and thereby caused these changes.