The effect of the timing of ethanol exposure during early postnatal life on total number of Purkinje cells in rat cerebellum

We have previously shown that exposing rats to a high dose of ethanol on po stnatal d 5 can affect Purkinje cell numbers in the cerebellum whilst simil ar exposure on d 10 had no such effect. The question arose whether a longer period of ethanol exposure after d 10 could produce loss of Purkinje cells . We have examined this question by exposing young rats to a relatively hig h dose (similar to 420-430 mg/dl) of ethanol for 6 d periods between the ag es of either 4 and 9 d or 10 and 15 d of age. Exposure was carried out by p lacing the rats in an ethanol vapour chamber for 3 h per day during the exp osure period. Groups of ethanol-treated (ET), separation controls (SC) and mother-reared controls (MRC) were anaesthetised and killed when aged 30 d b y perfusion with buffered 2.5 % glutaraldehyde. Stereological methods were used to determine the numbers of Purkinje cells in the cerebellum of each r at. MRC, SC and rats treated with ethanol between 10-15 d of age each had, on average, about 254-258 thousand cerebellar Purkinje cells; the differenc es between these various groups were not statistically significant. However , the rats treated with ethanol vapour between 4-9 d of age had an average of only about 128 000 +/- 20000 Purkinje cells per cerebellum. This value w as significantly different from both the MRC and group-matched SC animals. It is concluded that the period between 4 and 9 d of age is an extremely vu lnerable period during which the rat cerebellar Purkinje cells are particul arly susceptible to the effects of a high dose of ethanol. However, a simil ar level and duration of ethanol exposure commencing after 10 d of age has no significant effect on Purkinje cell numbers.