Type II corticosteroid receptor-like immunoreactivity in the rat cerebellar cortex: Differential regulation by corticosterone

Type II corticosteroid receptor-like immunoreactivity (type Il-ir) was localized at the light- and electron-microscopic levels in the rat cerebellar cortex using BUGR2 monoclonal antibody. In intact rats, type Il-ir was observed in the nuclei of basket, stellate, Golgi and Purkinje cells. After 1 week of adrenalectomy, type Il-ir was barely resolvable in basket, stellate, Golgi and most Purkinje cells. Vermal Purkinje cells showed intense nuclear and cytoplasmic type Il-ir. After 4 weeks of adrenalectomy, type Il-ir was markedly reduced in most vermal Purkinje cells, however a few in lobules 1-3 and 9 and 10 retained diffuse immunoreactivity. Acute treatment with corticosterone restored nuclear type Il-ir to basket, stellate, Golgi and Purkinje cells in the cerebellar hemispheres, flocculi and paraflocculi. In the vermis most Purkinje cells showed nuclear type Il-ir following corticosterone treatment. Diffuse type Il- ir was, however, retained in a few Purkinje cells in vermal lobules 1-3, 9 and 10. The distribution of GABA-like immunoreactivity (GABA-ir) in the cerebellar cortex was not altered by adrenalectomy or acute corticosterone treatment. 30-60% of type Il-ir Purkinje cells in intact rats were GABA-ir. In adre- nalectomized and corticosterone-treated rats, a similar proportion of type Il-ir Purkinje cells were GABA-ir. The differential regulation of neuronal type Il-ir in the cerebellum by corticosterone may account for some of the known effects of glucocorticoids on motor coordination.