RESUMO
Dopamine (DA) depletion in the dorsal striatum underlies symptoms of basal ganglia pathologies, including Parkinson's disease (PD). Various drug compounds are used to enhance DA levels for therapeutic purposes. Understanding neural signaling and movement patterns associated with over and understimulation of the DA system is essential. This study investigated striatal local field potential (LFP) oscillation and locomotor activity following treatments with morphine, a DA release enhancer, and haloperidol (HAL), a DA D2 receptor (D2R) antagonist in mice. After intracranial electrodes were placed into the dorsal striatum of male Swiss albino ICR mice, intraperitoneal injections of morphine or HAL were administered. LFP signals and spontaneous motor activity were recorded simultaneously. The results showed that morphine significantly increased locomotor speed, both low (30.3-44.9 Hz) and high (60.5-95.7 Hz) LFP gamma powers and delta (1-4 Hz)gamma (30.3-95.7 Hz) phaseamplitude coupling. In contrast, HAL treatments were found to significantly decrease these parameters. Moreover, regression analyses also revealed significant positive correlations between locomotor speed and high gamma powers. Taken together, these results demonstrate opposite LFP oscillations in the dorsal striatum with low and high gamma activities, and deltagamma couplings in response to a DA release enhancer and D2R antagonist by morphine and HAL, respectively. These parameters reflect fluctuation of neuronal activity in the dorsal striatum that might be useful for pathological research and drug discovery for PD.
