Parvalbumin‐containing GABAergic neurons in the basal ganglia output system of the rat

Abstract

The output of the basal ganglia is directed through the entopeduncular nucleus (EPN) and the substantia nigra pars reticulata (SNR) and pars lateralis (SNL), which provide a gamma-aminobutyric acidergic (GABAergic) projection to various nuclei of the thalamus and brainstem. Although many neurons within the SNR and EPN have been described as modality specific, the morphological and neurochemical similarities preclude their precise identification. In the present study, the immunocytochemical localization of parvalbumin, a calcium-binding protein, is used in combination with axonal tracing to verify neuronal heterogeneity within the SNR, SNL, and EPN. The results reveal that the majority of neurons in all three centers contain parvalbumin. The parvalbumin-containing neurons are distributed in the caudal two-thirds of the EPN, the rostral part of the SNL, and the lateral two-thirds of the entire rostrocaudal extent of the SNR, the areas involved in sensorimotor function of the basal ganglia. Moreover, the nigrothalamic, nigrocollicular, and EPN-thalamic neurons possess parvalbumin immunoreactivity, whereas the EPN-habenular neurons are devoid of parvalbumin immunoreactivity. The results indicate a neurochemical heterogeneity within the GABAergic output neurons of the basal ganglia and suggest that the parvalbumin-containing neurons of the SNR, SNL, and EPN are the tonically active output neurons that form a major link in the disinhibitory neuronal circuit of the basal ganglia, especially that concerned with sensorimotor function.

Neurogenesis in the mammalian neostriatum and nucleus accumbens: Parvalbumin-immunoreactive GABAergic interneurons

“…In agreement with previous studies (Gerfen et al, 1985;Celio, 1990;Cowan et al, 1990;Kita et al, 1990;Coté et al, 1991;Bennett and Bolam, 1994a,b;Rajakumar et al, 1994;Hussain et al, 1996;Sadikot et al, 1996), we find that PV-immunoreactive cell density at the lateral aspect of the precommissural striatum is greater than the medial part (Fig. 1).…”

“…In the basal ganglia, PV is localized in interneurons of the neostriatum and nucleus accumbens (Gerfen et al, 1985;Celio, 1990;Coté et al, 1991, Cowan et al, 1990Kita et al, 1990;Lapper et al, 1992;Bennett and Bolam, 1994a,b;Hussain et al, 1996;Sadikot et al, 1996), large GABAergic projection neurons of the pallidal segments, GABAergic neurons of the pars reticulata of the substantia nigra, and subpopulations of subthalamic nucleus cells (Gerfen et al, 1985;Celio, 1990;Coté et al, 1991;Rajakumar et al, 1994). Most neurons of the neostriatum and nucleus accumbens are medium-sized spiny projection neurons that use GABA as a neurotransmitter (Kitai et al, 1979;Chronister et al, 1981;Somogyi et al, 1981;Chang and Kitai, 1985).…”

Control of the Subthalamic Innervation of Substantia Nigra Pars Reticulata by D1 and D2 Dopamine Receptors

“…3C). Parvalbumin-positive cells of the SNr have been shown to contain GAD67 and be GABAergic projection neurons (Gerfen et al 1985;GonzalezHernandez and Rodriguez 2000;Hontanilla et al 1997;Parent et al 1996;Rajakumar et al 1994). These data then suggest that the most abundant neuron recorded was the GABAergic projection neuron of the SNr (Nakanishi et al 1987;Richards et al 1997).…”

Constitutively Active TRPC3 Channels Regulate Basal Ganglia Output Neurons

“…2). PV is a reliable marker for SNr GABA projection neurons whereas GABA synthesis enzyme GAD is not because of its low level at the soma (Rajakumar et al, 1994;Gonzalez-Hernandez and Rodriguez, 2000).…”