scholarly journals Presynaptic Modulation of Spontaneous Inhibitory Postsynaptic Currents by Gamma-hydroxybutyrate in the Substantia Nigra Pars Compacta

2003 ◽  
Vol 29 (3) ◽  
pp. 537-543 ◽  
Author(s):  
Alfredo Brancucci ◽  
Nicola Berretta ◽  
Nicola B Mercuri ◽  
Walter Francesconi
Keyword(s):  
Substantia Nigra ◽  
Substantia Nigra Pars Compacta ◽  
Presynaptic Modulation ◽  
Inhibitory Postsynaptic Currents ◽  
Postsynaptic Currents ◽  
Gamma Hydroxybutyrate

scholarly journals Regulation of Inhibitory Synapses by Presynaptic D4 Dopamine Receptors in Thalamus

2010 ◽  
Vol 104 (5) ◽  
pp. 2757-2765 ◽  
Author(s):  
Gubbi Govindaiah ◽  
Tongfei Wang ◽  
Martha U. Gillette ◽  
Shane R. Crandall ◽  
Charles L. Cox
Keyword(s):  
Substantia Nigra ◽  
Globus Pallidus ◽  
Receptor Agonist ◽  
Receptor Activation ◽  
Substantia Nigra Pars Compacta ◽  
Inhibitory Synapses ◽  
Reticular Nucleus ◽  
Postsynaptic Currents ◽  
Presynaptic Site ◽  
Site Of Action

Dopamine (DA) receptors are the principal targets of drugs used in the treatment of schizophrenia. Among the five DA receptor subtypes, the D4 subtype is of particular interest because of the relatively high affinity of the atypical neuropleptic clozapine for D4 compared with D2 receptors. GABA-containing neurons in the thalamic reticular nucleus (TRN) and globus pallidus (GP) express D4 receptors. TRN neurons receive GABAergic afferents from globus pallidus (GP), substantia nigra pars reticulata (SNr), and basal forebrain as well as neighboring TRN neuron collaterals. In addition, TRN receives dopaminergic innervations from substantia nigra pars compacta (SNc); however, the role of D4 receptors in neuronal signaling at inhibitory synapses is unknown. Using whole cell recordings from in vitro pallido-thalamic slices, we demonstrate that DA selectively suppresses GABAA receptor-mediated inhibitory postsynaptic currents (IPSCs) evoked by GP stimulation. The D2-like receptor (D2,3,4) agonist, quinpirole, and selective D4 receptor agonist, PD168077, mimicked the actions of DA. The suppressive actions of DA and its agonists were associated with alterations in paired pulse ratio and a decrease in the frequency of miniature IPSCs, suggesting a presynaptic site of action. GABAA receptor agonist, muscimol, induced postsynaptic currents in TRN neurons were unaltered by DA or quinpirole, consistent with the presynaptic site of action. Finally, DA agonists did not alter intra-TRN inhibitory signaling. Our data demonstrate that the activation of presynaptic D4 receptors regulates GABA release from GP efferents but not TRN collaterals. This novel and selective action of D4 receptor activation on GP-mediated inhibition may provide insight to potential functional significance of atypical antipsychotic agents. These findings suggest a potential heightened TRN neuron activity in certain neurological conditions, such as schizophrenia and attention deficit hyperactive disorders.

scholarly journals The tectonigral pathway regulates appetitive locomotion in predatory hunting in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Meizhu Huang ◽  
Dapeng Li ◽  
Xinyu Cheng ◽  
Qing Pei ◽  
Zhiyong Xie ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Superior Colliculus ◽  
Dopamine Release ◽  
Dorsal Striatum ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Neuronal Circuitry ◽  
Locomotion Speed ◽  
Brain Circuit ◽  
Goal Directed Behavior

AbstractAppetitive locomotion is essential for animals to approach rewards, such as food and prey. The neuronal circuitry controlling appetitive locomotion is unclear. In a goal-directed behavior—predatory hunting, we show an excitatory brain circuit from the superior colliculus (SC) to the substantia nigra pars compacta (SNc) to enhance appetitive locomotion in mice. This tectonigral pathway transmits locomotion-speed signals to dopamine neurons and triggers dopamine release in the dorsal striatum. Synaptic inactivation of this pathway impairs appetitive locomotion but not defensive locomotion. Conversely, activation of this pathway increases the speed and frequency of approach during predatory hunting, an effect that depends on the activities of SNc dopamine neurons. Together, these data reveal that the SC regulates locomotion-speed signals to SNc dopamine neurons to enhance appetitive locomotion in mice.

Struktur und Efferenzen der Substantia nigra pars compacta beim idiopathischen Parkinson-Syndrom

2020 ◽  
Vol 88 (09) ◽  
pp. 591-599
Author(s):  
Peter Urban ◽  
Bjorn Falkenburger ◽  
Wolfgang H. Jost ◽  
Gerhard Ransmayr ◽  
Peter Riederer ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Substantia Nigra Pars Compacta

ZusammenfassungEs besteht Konsens, dass das neuropathologische Merkmal des idiopathischen Parkinson-Syndroms (IPS) der neuronale Zellverlust der Substantia nigra pars compacta (SNc) in Verbindung mit einer Lewy-Pathologie ist. Die transsynaptische Ausbreitung der Lewy-Pathologie wird als wesentlich in der Parkinson-Pathogenese angesehen. Daher ist die Kenntnis präexistenter neuroanatomischer Verbindungen der SNc wesentlich. Wir beschreiben hier neuere tierexperimentelle Befunde zu den afferenten und efferenten Projektionen der SNc und diskutieren die Evidenz für und gegen die sequentielle transsynaptische Ausbreitung der Lewy-Pathologie in der Pathogenese des IPS.

scholarly journals Substantia nigra neuromelanin magnetic resonance imaging in patients with different subtypes of Parkinson disease

2021 ◽  
Author(s):  
Lu Wang ◽  
Yayun Yan ◽  
Liyao Zhang ◽  
Yan Liu ◽  
Ruirui Luo ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Substantia Nigra ◽  
Parkinson Disease ◽  
Clinical Symptoms ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Resonance Imaging ◽  
Mean Values

AbstractNeuromelanin (NM) is a dark pigment that mainly exists in neurons of the substantia nigra pars compacta (SNc). In Parkinson disease (PD) patients, NM concentration decreases gradually with degeneration and necrosis of dopamine neurons, suggesting potential use as a PD biomarker. We aimed to evaluate associations between NM concentration in in vivo SN and PD progression and different motor subtypes using NM magnetic resonance imaging (NM-MRI). Fifty-four patients with idiopathic PD were enrolled. Patients were divided into groups by subtypes with different clinical symptoms: tremor dominant (TD) group and postural instability and gait difficulty (PIGD) group. Fifteen healthy age-matched volunteers were enrolled as controls. All subjects underwent clinical assessment and NM-MRI examination. PD patients showed significantly decreased contrast-to-noise ratio (CNR) values in medial and lateral SN (P < 0.05) compared to controls. CNR values in lateral SN region decreased linearly with PD progression (P = 0.001). PIGD patients showed significant decreases in CNR mean values in lateral SN compared to TD patients (P = 0.004). Diagnostic accuracy of using lateral substantia nigra (SN) in TD and PIGD groups was 79% (sensitivity 76.5%, specificity 78.6%). NM concentration in PD patients decreases gradually during disease progression and differs significantly between PD subtypes. NM may be a reliable biomarker for PD severity and subtype identification.

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