Regulation of central alpha-adrenoceptors by serotoninergic denervation

Alpha 1- and alpha 2-adrenoceptors were assessed by binding studies using [3H]prazosin and [3H]p-aminoclonidine as ligands in membrane preparations from the cortex, hippocampus and hypothalamus of rats, 3 weeks after intracerebroventricular injection of the neurotoxin 5,7-dihydroxytryptamine. Cortical alpha 1 and hippocampal alpha 2 adrenoceptors were significantly increased. Treatment also affected the affinity of cortical alpha 2 adrenoceptors. These results suggest a heterologous, region-specific regulation of both subtypes of central alpha-adrenergic receptors by serotonin.