Author: Kalinichev, Mikhail; Easterling, Keith W.; Plotsky, Paul M.; Holtzman, Stephen G.
Description: Early neonatal environmental factors appear to have powerful and long-lasting influences on an organism’s physiology and behavior. Long-Evans male rats separated from their dam for 3 h daily over the first 2 weeks of life (maternally separated, MS rats) when tested as adults exhibit exaggerated behavioral and neuroendocrine responses to stress compared to 15-min separated (handled, H) animals. The purpose of this study was to compare male and female adult rats that were MS, H or were undisturbed (nonhandled, NH) as neonates in anxiety-like behaviors, in the elevated plus-maze, and in response to startle-inducing auditory stimuli. We confirmed that MS males oversecrete corticosterone (CORT; 2.5-5 times) in response to mild handling stress. MS males and females were less likely to explore open arms of the plus-maze. MS males exhibited 35% higher startle amplitudes compared to controls. Furthermore, MS males were more likely to emit ultrasonic vocalizations in response to startle than were H controls. However, MS and control females did not differ in auditory startle response or in startle-induced ultrasonic vocalizations. Therefore, experiencing maternal separation results in a long-lasting increase in anxiety-like behaviors that occurs in a sex-dependent manner.
Subject headings: Acoustic Stimulation; Animals; Animals, Newborn; Anxiety; Corticosterone; Female; Male; Maternal Deprivation; Pregnancy; Rats; Rats, Long-Evans; Stress, Physiological; Time; Vocalization; Animal
Publication year: 2002
Journal or book title: Pharmacology, Biochemistry, and Behavior
Volume: 73
Issue: 1
Pages: 131-140
Find the full text: https://www.sciencedirect.com/science/article/pii/S0091305702007815
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Serial number: 3794