Dopamine input to the striatum is required for voluntary motor movement, behavioral reinforcement, and responses to drugs of abuse. It is speculated that these functions are dependent on either excitatory or inhibitory modulation of corticostriatal synapses onto medium spiny neurons (MSNs). While dopamine modulates MSN excitability, a direct presynaptic effect on the corticostriatal input has not been clearly demonstrated. We combined optical monitoring of synaptic vesicle exocytosis from motor area corticostriatal afferents and electrochemical recordings of striatal dopamine release to directly measure effects of dopamine at the level of individual presynaptic terminals. Dopamine released by either electrical stimulation or amphetamine acted via D2 receptors to inhibit the activity of subsets of corticostriatal terminals. Optical and electrophysiological data suggest that heterosynaptic inhibition was enhanced by higher frequency stimulation and was selective for the least active terminals. Thus, dopamine, by filtering less active inputs, appears to reinforce specific sets of corticostriatal synaptic connections.
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http://dx.doi.org/10.1016/s0896-6273(04)00265-x | DOI Listing |
Zhejiang Da Xue Xue Bao Yi Xue Ban
January 2025
School of Medicine, Hangzhou City University, Zhejiang Provincial Key Laboratory of Novel Targets and Drug Study for Neural Repair, Hangzhou 310015, China.
Objectives: To investigate the protective effects and underlying mechanisms of extract on motor dysfunction in mouse model of Parkinson's disease (PD).
Methods: Eighty C57BL/6 male mice were randomly divided into five groups: control group, PD model group, levodopa treatment group (positive control group), low-dose GP treatment group (LD-GP group), and high-dose GP treatment group (HD-GP group), with 16 mice per group. The PD model was induced by injection of 6-hydroxydopamine into the substantia nigra pars reticulata in mice of last 5 groups.
Brain Behav Immun
January 2025
Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA; Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA. Electronic address:
Inflammatory stimuli administered to humans and laboratory animals affect mesolimbic and nigrostriatal dopaminergic pathways in association with impaired motivation and motor activity. Alterations in dopaminergic corticostriatal reward and motor circuits have also been observed in depressed patients with increased peripheral inflammatory markers. The effects of peripheral inflammation on dopaminergic pathways and associated neurobiologic mechanisms and consequences have been difficult to measure in patients.
View Article and Find Full Text PDFJ Neurosci
January 2025
Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, 9 Gronostajowa street, 30-387 Kraków, Poland.
Dopaminergic (DA) neurons of the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) play a crucial role in controlling animals' orienting and approach behaviors toward relevant environmental stimuli. The ventral midbrain receives sensory input from the superior colliculus (SC), a tectal region processing information from contralateral receptive fields of various modalities. Given the significant influence of dopamine release imbalance in the left and right striatum on animals' movement direction, our study aimed to investigate the lateralization of the connection between the lateral SC and the midbrain DA system in male rats.
View Article and Find Full Text PDFCurr Top Behav Neurosci
January 2025
Department of Neurobiology, University of Maryland, School of Medicine, Baltimore, MD, USA.
In the last two decades, the endocannabinoid system has emerged as a crucial modulator of motivation and emotional processing. Due to its widespread neuroanatomical distribution and characteristic retrograde signaling nature, cannabinoid type I receptors and their endogenous ligands finely orchestrate somatic and axon terminal activity of dopamine neurons. Owing to these unique features, this signaling system is a promising pharmacological target to ameliorate dopamine-mediated drug-seeking behaviors while circumventing the adverse side effects of, for instance, dopaminergic antagonists.
View Article and Find Full Text PDFbioRxiv
January 2025
Department of Physiology; David Geffen School of Medicine, University of California, Los Angeles, California.
The medial prefrontal cortex (mPFC) is required for learning associations that determine whether animals approach or avoid potential threats in the environment. Dopaminergic (DA) projections from the ventral tegmental area (VTA) to the mPFC carry information, particularly about aversive outcomes, that may inform prefrontal computations. But the role of prefrontal DA in learning based on aversive outcomes remains poorly understood.
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