Receptor modification in the brains of spontaneously hypertensive and Wistar-Kyoto rats: regionally specific and selective increase in cerebellar beta 2-adrenoceptors.

Quantitative in vitro autoradiography was used to study beta-adrenergic and benzodiazepine receptor density in discrete regions from sagittal brain sections of 20 week old hypertensive (SHR) and normotensive (WKY) rats. The density of beta-adrenoceptors was increased by 68% in the granule cell layer of the cerebellum of the SHR without a change in receptor affinity; this increase was specific for receptors of the beta 2-subtype. On the other hand, benzodiazepine receptor density was unchanged in the cerebella of SHR. These results indicate that brain beta-adrenoceptors are differentially modulated by the hypertensive state which may be either a cause or a consequence of alterations in adrenergic nervous system activity found in the SHR.