Prenatal stress alters spine density and dendritic length of nucleus accumbens and hippocampus neurons in rat offspring

Abstract

Prenatal stress alters neuronal morphology of mesocorticolimbic structures such as frontal cortex and hippocampus in the adult offspring. We investigated here the effects of prenatal stress on the spine density and the dendrite morphology of hippocampal pyramidal neurons and medium spiny cells from nucleus accumbens in prepubertal and adult male offsprings. Sprague-Dawley pregnant dams were stressed by restraining movement daily for 2 hours from gestational day 11 until delivery. Control mothers remained free in their home cage without water and food during the stressful event. Male offsprings from immobilized and control rats were left to grow until postnatal day (PD) 35 for the prepubertal group, and until PD 65 for the adult group. Spontaneous locomotor activity was assessed and then brains were removed to study the dendritic morphology by the Golgi-Cox stain method followed by Sholl analysis. Prenatally stressed animals demonstrated increased locomotion and alterations in spine density in the hippocampus and nucleus accumbens at both ages. However, prepubertal males showed an increase in spine density in the CA1 hippocampus with a decrease in CA3 hippocampus, whereas the adult group showed a decrease in the spine density in both of the regions studied. These results suggest that prenatal stress carried out during the middle of pregnancy affect the spine density and basal dendrites of pyramidal neurons of hippocampus, as well as the dendritic morphology of nucleus accumbens which may reflect important changes in the mesocorticolimbic dopaminergic transmission and behaviors associated with the development of psychiatric diseases such as schizophrenia.