ADRENERGIC-RECEPTORS IN THE CEREBELLUM OF OLIVOPONTOCEREBELLAR ATROPHY

Using autoradiographic techniques we studied the changes that in adren ergic receptors occurred in the cerebellum of two olivopontocerebellar atrophy (OPCA) patients as compared with a control group. In OPCA cer ebellum the densities of total beta-adrenoceptors were reduced along t he cortex but increased in the white matter. Although mainly the beta( 1) subtype was decreased along the cerebellar cortex, the increase of beta-receptors over the white matter was due to a selective raise in t he beta(1) subtype. These findings suggest a postsynaptic neuronal loc ation for the beta(1) subtype and a glial location for the beta(2)-adr enoceptor. On the other hand, alpha(2)-adrenoceptors were clearly redu ced all along the cerebellar cortex of these OPCA brains, this probabl y being secondary to the loss of presynaptic adrenergic terminals aris ing from the locus coeruleus. These results help clarify both the subc ellular location of adrenoceptors in human cerebellum and the neuroche mical pathophysiology of OPCA.