Effect of alcohol on neurons of iso-cortex--a histomorphometric study

Effect of chronic intake of alcohol and its subsequent withdrawal was studied in albino mice on the layers of neurons of the iso-cortex. Neuronal density per mm2 of section in different layers of iso-cortex was counted and compared in 3 groups of animals (control, ethanol fed and withdrawal). Qualitative changes on nissl granules of neurons and myelinated fibres were also studied. Mice fed with 10% ethanol v/v ad libitum for 6 months showed loss of nissl granules and nucleolus and discontinuity of nuclear membrane. Quantitatively, significant reduction in neuronal density (P<0.001) was observed in layers II+III IV and V neurons of iso-cortex. Withdrawal of ethanol for 2 months showed continued reduction of counts of neuronal density in layers II+III and V only whereas reversal of count was found significantly (P<0.001) in layer IV of iso-cortex. Qualitatively, only few neurons showed prominent nissl granules after withdrawal of ethanol. More afferent synaptic connection in layer IV may be suggested as probable factor helping relative replenishment of neuronal count after withdrawal of alcohol.