Substantia nigra 6-hydroxydopamine lesions alter dopaminergic synaptic markers in the nucleus basalis magnocellularis and striatum of rats

Abstract

Recent findings have demonstrated the existence of dopaminergic (DA) markers in the nbM of the human brain and a reduction of these markers in both the nbM and the striatum of patients suffering from Alzheimer's disease (AD). To investigate the source of the DA synaptic markers found in the nbM, rats received unilateral 6‐OHDA lesions of the substantia nigra pars compacta (SNc). The SNc lesions caused signigificant reductions in DA and DOPAC but not HVA in the nbM and the striaum; ³H‐sulpiride binding to D₂ receptors ipsilateral to the SNc lesion was significantly increased in the stratum (16%), consistent with denervation supersensitivity, but single‐point analysis showed no significant changes in the nbM. These data suggest that the decreases in DA and ³H‐spiperone binding levels observed in the nbM of AD patients may be due to partial destruction of DA nbM afferent projections from the brainstem.