GABA B receptor-mediated modulation of the firing pattern of ventral tegmental area dopamine neurons in vivo

2002 ◽  
Vol 365 (3) ◽  
pp. 173-180 ◽  
Author(s):  
Sophie Erhardt ◽  
Jan Mathé ◽  
Karima Chergui ◽  
Göran Engberg ◽  
Torgny Svensson
Keyword(s):  
Ventral Tegmental Area ◽  
Firing Pattern ◽  
Dopamine Neurons ◽  
Ventral Tegmental

Slow Oscillatory Firing: A Major Firing Pattern of Dopamine Neurons in the Ventral Tegmental Area

2005 ◽  
Vol 94 (5) ◽  
pp. 3516-3522 ◽  
Author(s):  
Wei-Xing Shi
Keyword(s):  
Ventral Tegmental Area ◽  
Single Unit ◽  
Firing Pattern ◽  
Receptor Activation ◽  
Dopamine Neurons ◽  
Interspike Intervals ◽  
Firing Activity ◽  
Unit Recording ◽  
Ventral Tegmental

Using spectral analysis and in vivo single-unit recording in rats, the present study revealed a pronounced slow oscillation (SO) in the firing activity of about half the dopamine (DA) neurons recorded in the ventral tegmental area. DA neurons in this group tended to fire repetitive spike clusters, making them appear to be rhythmic bursting cells. However, only some of these burst-like events met the traditional “80/160 ms” burst criteria entirely. The observation that the SO could be found in nonbursting DA cells, occurred at frequencies different from those of bursts, and persisted after bursts were digitally removed from spike trains further supports the suggestion that the SO is different from the traditionally defined bursting. Interspike intervals (ISIs) had been thought to be bimodally distributed in bursting DA neurons. This study found that some nonbursting DA cells also had a bimodal ISI distribution and a significant number of bursting cells did not. In the majority of cells where less than half the spikes occurred in bursts, a bimodal ISI distribution was highly predictive of the presence of the SO. Results further showed that the generation of the SO required forebrain inputs to DA neurons but not the adrenergic α1 receptor activation responsible for psychostimulant-induced increases in the SO. Taken together, these results suggest that the SO is distinct from the traditionally defined bursting and represents a major firing pattern of DA neurons in the ventral tegmental area.

Long-lasting synaptic regulation of dopamine neurons by astrocytes in the Ventral Tegmental Area

2021 ◽  
Author(s):  
Linda Requie ◽  
Marta Gómez-Gonzalo ◽  
Francesca Managò ◽  
Mauro Congiu ◽  
Marcello Melone ◽  
...  
Keyword(s):  
Ventral Tegmental Area ◽  
Metabotropic Glutamate Receptor ◽  
Receptor Activation ◽  
Dopamine Neuron ◽  
Dopamine Neurons ◽  
Neuron Activity ◽  
Astrocytic Process ◽  
Metabotropic Glutamate ◽  
Ventral Tegmental

Abstract The plasticity of glutamatergic transmission in the Ventral Tegmental Area (VTA) represents a fundamental mechanism in the modulation of dopamine neuron burst firing and the phasic dopamine release at VTA target regions. These processes encode basic behavioral responses, including locomotor activity, learning and motivated-behaviors. Here we describe a hitherto unidentified mechanism of long-lasting potentiation of glutamatergic synapses on DA neurons. We found that VTA astrocytes respond to dopamine neuron bursts with Ca2+ elevations that require activation of endocannabinoid CB1 and dopamine D2 receptors colocalized at the same astrocytic process. Astrocytes, in turn, release glutamate that, through presynaptic metabotropic glutamate receptor activation coupled with neuronal nitric oxide production, induces long-lasting potentiation of excitatory synapses on adjacent dopamine neurons. Consistent with this finding, selective activation of VTA astrocytes increases dopamine neuron bursts in vivo and induces locomotor hyperactivity. Astrocytes play, therefore, a key role in the modulation of VTA dopamine neuron activity.

scholarly journals Increased dopamine D2 receptor activity in the striatum alters the firing pattern of dopamine neurons in the ventral tegmental area

2015 ◽  
Vol 112 (12) ◽  
pp. E1498-E1506 ◽  
Author(s):  
Sabine Krabbe ◽  
Johanna Duda ◽  
Julia Schiemann ◽  
Christina Poetschke ◽  
Gaby Schneider ◽  
...  
Keyword(s):  
Ventral Tegmental Area ◽  
Cognitive Deficits ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
Dopamine Neurons ◽  
Tonic Activity ◽  
Functional Deficits ◽  
The Core ◽  
Ventral Tegmental

There is strong evidence that the core deficits of schizophrenia result from dysfunction of the dopamine (DA) system, but details of this dysfunction remain unclear. We previously reported a model of transgenic mice that selectively and reversibly overexpress DA D2 receptors (D2Rs) in the striatum (D2R-OE mice). D2R-OE mice display deficits in cognition and motivation that are strikingly similar to the deficits in cognition and motivation observed in patients with schizophrenia. Here, we show that in vivo, both the firing rate (tonic activity) and burst firing (phasic activity) of identified midbrain DA neurons are impaired in the ventral tegmental area (VTA), but not in the substantia nigra (SN), of D2R-OE mice. Normalizing striatal D2R activity by switching off the transgene in adulthood recovered the reduction in tonic activity of VTA DA neurons, which is concordant with the rescue in motivation that we previously reported in our model. On the other hand, the reduction in burst activity was not rescued, which may be reflected in the observed persistence of cognitive deficits in D2R-OE mice. We have identified a potential molecular mechanism for the altered activity of DA VTA neurons in D2R-OE mice: a reduction in the expression of distinct NMDA receptor subunits selectively in identified mesolimbic DA VTA, but not nigrostriatal DA SN, neurons. These results suggest that functional deficits relevant for schizophrenia symptoms may involve differential regulation of selective DA pathways.

scholarly journals Dendritic Architecture Predicts in vivo Firing Pattern in Mouse Ventral Tegmental Area and Substantia Nigra Dopaminergic Neurons

2021 ◽  
Vol 15 ◽  
Author(s):  
Trinidad Montero ◽  
Rafael Ignacio Gatica ◽  
Navid Farassat ◽  
Rodrigo Meza ◽  
Cristian González-Cabrera ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Ventral Tegmental Area ◽  
Cell Body ◽  
Firing Pattern ◽  
Dendritic Tree ◽  
Dendritic Morphology ◽  
Substantia Nigra Pars Compacta ◽  
Ventral Tegmental ◽  
Firing Properties

The firing activity of ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) dopaminergic (DA) neurons is an important factor in shaping DA release and its role in motivated behavior. Dendrites in DA neurons are the main postsynaptic compartment and, along with cell body and axon initial segment, contribute to action potential generation and firing pattern. In this study, the organization of the dendritic domain in individual VTA and SNc DA neurons of adult male mice, and their relationship to in vivo spontaneous firing, are described. In comparison with dorsal VTA DA neurons, ventrally located VTA neurons (as measured by cell body location) possess a shorter total dendritic length and simpler dendritic architecture, and exhibit the most irregular in vivo firing patterns among DA neurons. In contrast, for DA neurons in the SNc, the higher irregularity of firing was related to a smaller dendritic domain, as measured by convex hull volumes. However, firing properties were also related to the specific regional distribution of the dendritic tree. Thus, VTA DA neurons with a larger extension of their dendritic tree within the parabrachial pigmented (PBP) nucleus fired more regularly compared with those with relatively more dendrites extending outside the PBP. For DA neurons in the SNc, enhanced firing irregularity was associated with a smaller proportion of dendrites penetrating the substantia nigra pars reticulata. These results suggest that differences in dendritic morphology contribute to the in vivo firing properties of individual DA neurons, and that the existence of region-specific synaptic connectivity rules that shape firing diversity.

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