Autoradiographic analysis of D 1 and D 2 dopaminergic receptors in rat brain after paradoxical sleep deprivation

Abstract

Previous work had shown that paradoxical sleep deprivation (PSD) results in potentiation of several apomorphine-induced behaviors, leading to the suggestion that PSD induces an upregulation of brain dopamine receptors. In this study, quantitative receptor autoradiography was used to verify whether PSD does, in fact, induce alterations in D 1 or D 2 receptor binding, and to investigate the regional brain specificity of such effects. After 96 h of PSD, [ 3H]SCH-23390 binding to D 1 receptors was examined in 30 different brain areas of 10 experimental and 10 cage control rats. [ 3H]Spiperone was used to label D 2 sites in adjacent tissue sections. Results revealed a 39% increase in [ 3H]SCH 23390 binding in the entorhinal cortex of PSD rats ( p < 0.05), but no other changes in any of the remaining 29 brain areas examined. In contrast, [ 3H]spiperone binding was significantly elevated in the n. accumbens (+45%) and in all subrogions of the caudate-putamen (range: +13% to +23%). These results, thus, provide evidence that PSD increases D 2 but not D 1 receptor binding in brain. The present results also suggest that upregulated D 2 receptors can account for the previously reported changes in apomorphine-induced behaviors after PSD.