Basal ganglia function

In the classical model of basal ganglia function, neurons in the direct pathway were conceptualized as bearing Dl receptors and co-expressing substance P and dy-norphin. Neurons in the indirect pathway had Dj receptors and co-expressed enkephalin. The direct pathway was viewed as releasing movement through disinhibition of the thalamus, whereas enhancing the excitatory activity of the indirect pathway decreased motor activity (Chevalier and Deniau, 1990). This system of checks and balances can be disrupted in several ways. When there is a decrease of normal dopaminergic input, as it is in PD, the excessive output from... 

Because of the key role which dopamine plays in basal ganglia function, and the evidence that its deficiency results in Parkinson s disease, there are three main approaches to the effective treatment of the symptoms of the disease ... 

Sano H, Yasoshima Y, Matsushita N, Kaneko T, Kohno K, Pastan I, Kobayashi K (2003) Conditional ablation of striatal neuronal types containing dopamine D2 receptor disturbs coordination of basal ganglia function. J Neurosci 23 9078-9088. 

Knockout mice in understanding basal ganglia function and sprouting... 

Overall, as predicted by anatomical organization and connectivity, the ventral tier nigrostriatal dopaminergic system is primarily associated with basal ganglia function related to motor behavior, whereas the dorsal tier mesocorticolimbic system is more linked to the neural structures involved in reinforcement, motivation, emotion and cognitive function. 

As indicated above, the administration of different cannabinoids impairs movement in rodents and humans. It is expected that this effect depends on the direct or indirect action of cannabinoids on the levels of several neurotransmitters that have been classically involved in the control of basal ganglia function. Three neurotransmitters seem to be influenced by cannabinoids in this circuitry, dopamine, y-aminobutyric acid (GABA), and glutamate. In the case ofthe last two neurotransmitters, a direct action is possible since GABAergic and glutamatergic neurons in the basal ganglia contain CBi receptors located presynaptically (see Fig. 1). This... 

Fernandez-Ruiz J, Lastres-Becker 1, Cabranes A, Gonzdlez S, Ramos JA (2002) Endocannabinoids and basal ganglia functionality. Prostaglandins Leukot Essent Patty Acids 66 263-273... 

Although the dopamine input the striatum is the dominant input from the midbrain and brainstem at least two other forebrain projection sytems provide inputs. These include a serotonergic input from the dorsal raphe and a noradrenergic input from the locus coeruleus. Added to the list of sources of afferents to the striatum not covered in depth by this review are those from the amygdala. These inputs will not be dealt with in this review, which does not reflect their probable important contribution to basal ganglia function. 

Fernandez-Ruiz, J., Lastres-Becker, I., Cabranes, A., Gonzalez, S., and Ramos, J.A. (2002) Endocaimabinoids and basal ganglia functionality. Prostaglandins, Leukotrienes and Essential Fatty Acids 66 257-267. 

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