We have previously shown that exposing rats to a high dose of ethanol on postnatal d 5 can affect Purkinje
cell numbers in the cerebellum whilst similar 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 high dose (∼420–430 mg/dl) of ethanol for
6 d periods between the ages of either 4 and 9 d or 10 and 15 d of age. Exposure was carried out by placing
the rats in an ethanol vapour chamber for 3 h per day during the exposure period. Groups of ethanol-treated (ET), separation controls (SC) and mother-reared controls (MRC) were anaesthetised and killed
when aged 30 d by perfusion with buffered 2.5% glutaraldehyde. Stereological methods were used to
determine the numbers of Purkinje cells in the cerebellum of each rat. 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
differences 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 128000±20000 Purkinje cells per
cerebellum. This value was 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 vulnerable period during which the rat
cerebellar Purkinje cells are particularly susceptible to the effects of a high dose of ethanol. However, a
similar level and duration of ethanol exposure commencing after 10 d of age has no significant effect on
Purkinje cell numbers.