Mechanisms of ethanol-induced degeneration in the developing, mature, and aging cerebellum

The adverse effects of acute and chronic ethanol exposure on cerebellar functions have been acknowledged for decades, in terms of impaired control of movement and balance. In addition to the motor impairment, cerebellar degeneration has recently been shown to contribute to distinct neuropsychological deficits in chronic alcoholics, as well as in children with prenatal ethanol exposure. The basic mechanisms underlying these ethanol-induced functional alterations and the related neuropathology in the cerebellum have mostly been clarified only recently. These mechanisms include: (i) excitotoxicity; (ii) dietary factors, especially thiamine depletion; (iii) glial abnormalities; (iv) changes in growth factors; (v) apoptotic mechanisms; (vi) oxidative stress; and (vii) compromised energy production. Although these mechanisms widely apply not only to the mature cerebellum, but also to the developing and the aging cerebella, the developing and the aged cerebellum have some special characteristics, which may make them even more vulnerable to ethanol-induced degeneration. These special instances will be discussed along with the general mechanisms of ethanol-induced cerebellar degeneration.