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[Display omitted] • D1R and D2R neurons in the GPi show distinct electrophysiological properties. • D2R neurons exhibit altered action potential responses in 6-OHDA-lesioned mice. • Alterations in D2R neuron electrophysiology may contribute to PD pathophysiology. Parkinson's disease (PD) ranks as the second most prevalent and rapidly growing neurodegenerative disorder. As a primary output nucleus within the basal ganglia (BG), the globus pallidus interna (GPi) is a key structure in BG information processing. It is also a key target for deep brain stimulation (DBS) to alleviate motor symptoms of PD. Previous studies have identified PD patients exhibiting abnormal neuronal activity in the GPi. On the other hand, various types of dopamine receptor (DR)-positive neurons have been identified within the GPi. However, the electrophysiological properties of specific DR-positive neurons within the GPi and their alterations in PD have not been addressed. In the present study, we used whole-cell patch-clamp recordings to identify two neuronal subpopulations within the GPi, dopamine D1 receptor (D1R)-positive, and dopamine D2 receptor (D2R)-positive neurons, which exhibited distinct electrophysiological properties. Additionally, significant alterations of electrophysiological properties of D2R-positive neurons within the GPi were observed in 6-hydroxydopamine (6-OHDA)-lesioned mice. These data suggest that the distinct electrophysiological properties of specific DR-positive neurons and their abnormal alteration in the GPi may be associated with PD's pathogenesis. [ABSTRACT FROM AUTHOR]

In this study, the effect of repetitive transcranial magnetic stimulation (rTMS) on the kindling induced changes in electrophysiological firing properties of hippocampal CA1 pyramidal neurons was investigated. Male Wistar rats were kindled by daily electrical stimulation of the basolateral amygdala in a semi-rapid manner (12 stimulations/day) until they achieved stage-5 seizure. One group (kindled+rTMS (KrTMS)) of animals received rTMS (240 pulses at 1 Hz) at 5 min after termination of daily kindling stimulations. Twenty-four hours following the last kindling stimulation electrophysiological properties of hippocampal CA1 pyramidal neurons were investigated using a whole-cell patch clamp technique, under current clamp condition. Amygdala kindling significantly decreased the adaptation index, post-afterhyperpolarization, rheobase current, utilization time, and delay to the first rebound spike. It also caused an increase in the voltage sag, number of rebound spikes and number of evoked action potential. Results of the present study revealed that application of rTMS following kindling stimulations had antiepileptogenic effects. In addition, application of rTMS prevented hyperexcitability of CA1 pyramidal neurons induced by kindling and conserved the normal neuronal firing. [ABSTRACT FROM AUTHOR]