Neuropathological characteristics and alteration of the dopamine D2 receptor in hypoxic-ischemic basal ganglia necrosis

The neuropathological characteristics and alteration of the dopamine D2 receptor (D2R) were investigated in 27 cases of hypoxic-ischemic basal ganglia necrosis (BGN) by means of neuropathological and immunohistochemical methods. Perinatal hypoxic-ischemic BGN manifested neuronal karyorrhexis as well as eosinophilia, karyorrhexis being more predominant in preterm infants and eosinophilia more predominant in full-term infants. Immunoreactivity to D2R was detected in the cytoplasm and dendrites of small and large neurons in the basal ganglia, and increased with neuronal maturation during the late gestational period in normal human basal ganglia. The number of D2R-positive neurons was smaller in all cases of acute BGN than that in controls, the areas of decreased D2R-positive neurons corresponding to the damaged regions observed on HE staining. Furthermore, neurons showed high expression of D2R in a few cases of remote BGN, suggesting some plasticity as to the recovery of D2R. Thus, the neuropathological characteristics of perinatal hypoxic-ischemic BGN may be related to neuronal maturation during different developmental stages in each region, and D2R development may play a role in the basal ganglia vulnerability to hypoxic-ischemia.