Brain Noradrenergic Receptors in Major Depression and Schizophrenia

The binding of [125I]p-iodoclonidine to alpha-2, and/or [125I]iodopindolol to beta-1 and beta-2 adrenoceptors was measured in right prefrontal cortex (Brodmann’s area 10) and right hippocampus from subjects with DSM-III-R diagnoses of major depression (n = 15) or schizophrenia (n = 8) as well as from control subjects (n = 20). No significant differences between study groups were observed in binding to alpha-2 adrenoceptors in any of the six layers of prefrontal cortex or in any of the hippocampal fields. Likewise, there were no significant differences in beta-1 or beta-2 adrenoceptor binding in any of the hippocampal fields between control and major depressive subjects. In contrast, binding to beta-1 adrenoceptors, but not beta-2 adrenoceptors, was significantly lower (−13 to −27%) in most hippocampal fields of schizophrenic subjects as compared to control subjects or to major depressives. Alterations in beta-1 adrenoceptor binding in the hippocampus of schizophrenics provide further evidence for a role of central noradrenergic neurons in the neurochemical pathology of schizophrenia.