Effects of chronic ethanol consumption beginning at adolescence: increased numbers of dendritic spines on cortical pyramidal cells in the adulthood

Summary To increase our understanding of the effects of chronic ethanol consumption beginning at adolescence, 25% ethanol in drinking water (v/v) was administered daily to young rats aged 45–50 days for 5 months. Increased numbers of dendritic spines on the apical dendrite of layer V pyramidal neurons of the somatosensory cortex (U-Mann-Whitney test,P<0.01–0.05) were found in almost every 50-m-long segment over a distance of 500 m from the cell body in ethanol-treated rats at the age of 195–200 days when compared with age-matched controls. Although the mechanisms leading to this unusual finding are not know, it is suggested that impairment of the naturally occurring elimination of redundant synapses can not be ruled out.