Prenatal morphine exposure alters the layer II/III pyramidal neurons morphology in lateral secondary visual cortex of juvenile rats.

Altered cortical neuronal morphology and juvenile behavior manifestation by prenatal morphine exposure were well documented. However, this developmental morphine exposure affect the lateral secondary visual area (V2L), which may be critically involved in the multisensory of auditory and visual stimulus, remained poorly understood. To clarify the neuronal architecture changes possibly occurring in the V2L, Golgi-Cox staining was used in this study to count dendritic length and the spine density of the layer II/III pyramidal neurons in the V2L of the juvenile rats (postnatal day 25, PND25) prenatally exposed to morphine (gestation days 11-18). Quantitative analysis showed that prenatal morphine exposure decreased the total length, branch number, and spine density of the layer II/III pyramidal neurons in the V2L, and selectively altered the total length of the basal dendrites but not of the apical dendrites. The findings may provide the mechanistic understanding of the behavioral changes in the children whose mothers abuse opiates during pregnancy.