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

Abstract

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 less than 0.01-0.05) were found in almost every 50-micron-long segment over a distance of 500 microns 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.

Dendritic Alterations of Cortical Pyramidal Neurons in Postnatally Lead-Exposed Kittens: A Golgi-Cox Study

“…These facts would thus argue that malnourishment is not a fac tor in the formation of hyperspiny neurons in this study. Ferrer [26] suggested that the increase in spines in alcohol-treated rats was due to a failure of the normal elimination of redundant synapses and that it may reflect delayed maturation of cortical circuits. In a Golgi study of reticular and nonreticular brainstem neurons from infants succumbing to sudden infant death syndrome (SIDS), Quattrochi et al [55] described hyper spiny dendrites in both cell populations.…”

Ethanol enhances growth factor activation of mitogen-activated protein kinases by a protein kinase C-dependent mechanism.

“…We previously reported that enhancement of NGF-induced neurite outgrowth by ethanol was inhibited by downregulation of ,B, 6, and s isoforms of protein kinase C (PKC) (14). We also found that exposure to 25-100 mM ethanol for 2-6 days increased levels of mRNA (15) and protein (16) for 8 and s PKC and activated PKC in PC12 cells (16). Taken together, these findings suggest that ethanol enhances neurite formation by activating specific isozymes of PKC.…”

“…Although early studies showed that ethanol inhibited neurite growth in some neurons (3,4), several reports (5)(6)(7)(8)(9)(10) indicate that ethanol markedly enhances neurite growth in several brain regions. For example, in adult rats, chronic ethanol exposure increases the length of dendrites in cerebellar Purkinje cells and hippocampal dentate granule cells and the number of dendritic spines on dentate granule cells and somatosensory cortical neurons (5)(6)(7)(8). Prenatal ethanol exposure increases dendritic arborization in layer Vb somatosensory corticospinal neurons and causes hyperdevelopment of hippocampal dentate granule cell axons (9,10).…”

“…PC12 cells were grown in flasks for 4 days with or without 100 mM ethanol and then were plated on polyornithine-coated 100-mm dishes at [6][7][8] containing 0.2% Tween 20 (TBS-T). Blots were then incubated with anti-phosphotyrosine antibody (1 ,tg/ml in blocking solution) for 2-3 hr at 25°C and washed for 10 min three times in TBS-T. After incubation for 1 hr at 25°C with peroxidaseconjugated anti-mouse antibody (1:1000 dilution), blots were washed four times in TBS-T, incubated with ECL detection reagent, and exposed to Kodak X-Omat AR film.…”

Ethanol‐Induced Cas Tyrosine Phosphorylation and Fyn Kinase Activation in Rat Brain

“…Results are representative of two independent experiments with similar results. dendritic segments in cerebellar Purkinje cells (Pentney and Quackenbush, 1990) and the number of dendritic spines on dentate granule cells (King et al, 1988) and somatosensory cortical pyramidal cells (Ferrer et al, 1989). In addition, ethanol has been shown to enhance neurite growth in cultured cerebellar neurons (Zou et al, 1993) and in growth factor-treated PC12 cells (Messing et al, 1991).…”