Adaptation and habituation of heart rate to handling in the rat.

Abstract

To determine effects of removal from home cage, manual manipulation, and placement in a new environment on heart rate (HR), dermal EKG electrodes were implanted in albino rats. HR was recorded for 13 Ss placed in a wood box for 2 min. on each of 20 consecutive days in Phase 1 and for 7 Ss placed in the box for 1 hr. on each of 10 consecutive days in Phase 2. Subsequently, 4 of these Ss were given 5 additional daily 4-hr. exposures and a single 24-hr. exposure to the apparatus. Handling produced marked acceleration in HR which dissipated in a negatively accelerated fashion over 3 hr. Successive experiences with handling did not reduce HR acceleration.