Failure of severe maternal stress or ACTH during pregnancy to affect emotionality of male rat offspring: implications of litter effects for prenatal studies.

Daily maternal neck restraint, whole body restraint, hyperthermia, and ACTH treatment during the last 3rd of gestation had no reliable effect on open-field and cage-emergence behavior in male Sprague-Dawley offspring. Many of these treatments, however, produced considerable maternal pathology and evidence for maternal adrenocorticoid release. Significant litter effects were found for almost every morphological and behavioral measure. Failure to control for the litter variable may account for many previously reported effects of prenatal stress on emotionality in rats. Female rats showed greater activity and less defecation than males on postpubertal open-field and cage emergence tests.