Substantia nigra pars reticulata

Substantia nigra pars reticulata is the area with highest neuronal activity and metabolic rate in the brain. This region also shows highest expression rates of SUR1/ Kir6.2 channels. These KATP channels are present... 

EFFECTS OF AMPHETAMINE ON SUBSTANTIA NIGRA PARS RETICULATA NEURONS IN BEHAVING RATS... 

FIGURE 3. Amphetamine increases the firing rate of a substantia nigra pars reticulata neuron in the chronically implanted, behaving rat... 

Waszezak, B.L., and Walters, J.R. Dopamine modulation of the effects of y-aminobutyric acid on substantia nigra pars reticulata neurons. Science 220 218-221, 1983. 

Mesencephalon substantia nigra-pars reticulata, interpeduncular nucleus, central gray ventral tegmental area, laterodorsal tegmental nucleus, interpeduncular nucleus... 

Cerebral cortex (layer I-VI, selected interneurons and principal cells) hippocampus (selected interneurons and principal cells) pallidum striatum (interneurons) thalamic relay nuclei olfactory bulb (mitral cells and interneurons) cerebellum (Purkinje cells and granule cells) deep cerebellar nuclei amygdala basal forebrain substantia nigra pars reticulata inferior colliculus brainstem... 

H3 receptor activation selectively inhibits dopamine D receptor-dependent [3H]GABA release from depolarization-stimulated slices of rat substantia nigra pars reticulata. Neuroscience 80 241-249. 

Garcia, M., Floran, B., Arias-Montano, J.A., Young, J.M. and Aceves, J. (1997). Histamine H3-receptor activation selectively inhibits dopamine Di-dependent [3H]-Y-aminobutyric acid release from depolarisation-stimulated slices of rat substantia nigra pars reticulata. Neuroscience, in press. 

Autoradiographic localization of brain cannabinoid receptors using a labeled probe has revealed a unique distribution. Binding is most dense in the outflow nuclei of the basal ganglia, in the substantia nigra pars reticulata, the globus pallidus, the hippocampus, and cerebellum. 

A major effect of Huntington s chorea is the loss of neostriatal neurons, accompanied by the loss of dopamine Dj receptors. A group of investigators has found that this loss of neurons also causes a 97.5% reduction of CBj receptors in the substantia nigra pars reticulata. On the basis of these data, the authors have suggested a role for cannabinoids in the control of movement in, and possibly in the therapeutics or symptomology of, hyperkinetic and dystonic disorders, such as Huntington s disease, as well is in the treatment of Parkinson s disease. 

A G protein-coupled cannabinoid receptor (CB1) is most numerous in the outflow nuclei of the basal ganglia, the substantia nigra, pars reticulata, globus pallidus, hippocampus, and brainstem. Positron emission tomographic (PET) studies have revealed increases in metabolism following THC in the same areas in which receptors are localized, suggesting that these receptors are closely involved in the clinical actions of the drug. 

A final general observation on Table 1 is that, in several cases, both facilitation through Di-like and inhibition by D2-like receptors have been reported. This holds true for noradrenaline release in rat nucleus accumbens, acetylcholine release in rat striatum, GABA release in rat striatum, nucleus accumbens, and ventral tegmental area (VTA), and glutamate release in rat substantia nigra pars reticulata. 

Marino, M. J., Wittmann, M., Bradley, S. R., Hubert, G. W., Smith, Y., and Conn, P. J. (2001). Activation of group I metabotropic glutamate receptors produces a direct excitation and disinhi-bition of GABAergic projection neurons in the substantia nigra pars reticulata. J. Neurosci. 15,... 

Stanford IM, Lacey MG. Differential actions of serotonin, mediated by 5-HT1B and 5-HT2C receptors, on GABA-mediated synaptic input to rat substantia nigra pars reticulata neurons in vitro. J Neurosci 1996 16 7566-7573. 

On the other hand, the presence of abundant 5-HT1B receptors in the basal ganglia and their role in modulating the activity of output GABAergic neurons in the substantia nigra pars reticulata (191) suggests a possible role of 5-HT1B... 

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