scholarly journals KV7 Channels Regulate Firing during Synaptic Integration in GABAergic Striatal Neurons

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
M. Belén Pérez-Ramírez ◽  
Antonio Laville ◽  
Dagoberto Tapia ◽  
Mariana Duhne ◽  
Esther Lara-González ◽  
...  

Striatal projection neurons (SPNs) process motor and cognitive information. Their activity is affected by Parkinson’s disease, in which dopamine concentration is decreased and acetylcholine concentration is increased. Acetylcholine activates muscarinic receptors in SPNs. Its main source is the cholinergic interneuron that responds with a briefer latency than SPNs during a cortical command. Therefore, an important question is whether muscarinic G-protein coupled receptors and their signaling cascades are fast enough to intervene during synaptic responses to regulate synaptic integration and firing. One of the most known voltage dependent channels regulated by muscarinic receptors is theKV7/KCNQ channel. It is not known whether these channels regulate the integration of suprathreshold corticostriatal responses. Here, we study the impact of cholinergic muscarinic modulation on the synaptic response of SPNs by regulatingKV7 channels. We found thatKV7 channels regulate corticostriatal synaptic integration and that this modulation occurs in the dendritic/spines compartment. In contrast, it is negligible in the somatic compartment. This modulation occurs on sub- and suprathreshold responses and lasts during the whole duration of the responses, hundreds of milliseconds, greatly altering SPNs firing properties. This modulation affected the behavior of the striatal microcircuit.

Synapse ◽  
2018 ◽  
Vol 73 (4) ◽  
pp. e22079 ◽  
Author(s):  
Brisa García-Vilchis ◽  
Paola Suárez ◽  
Miguel Serrano-Reyes ◽  
Mario Arias-García ◽  
Dagoberto Tapia ◽  
...  

2013 ◽  
Vol 109 (4) ◽  
pp. 1140-1151 ◽  
Author(s):  
Hiroshi Yamada ◽  
Hitoshi Inokawa ◽  
Naoyuki Matsumoto ◽  
Yasumasa Ueda ◽  
Kazuki Enomoto ◽  
...  

Decisions maximizing benefits involve a tradeoff between the quantity of a reward and the cost of elapsed time until an animal receives it. The estimation of long-term reward values is critical to attain the most desirable outcomes over a certain period of time. Reinforcement learning theories have established algorithms to estimate the long-term reward values of multiple future rewards in which the values of future rewards are discounted as a function of how many steps of choices are necessary to achieve them. Here, we report that presumed striatal projection neurons represent the long-term values of multiple future rewards estimated by a standard reinforcement learning model while monkeys are engaged in a series of trial-and-error choices and adaptive decisions for multiple rewards. We found that the magnitude of activity of a subset of neurons was positively correlated with the long-term reward values, and that of another subset of neurons was negatively correlated throughout the entire decision-making process in individual trials: from the start of the task trial, estimation of the values and their comparison among alternatives, choice execution, and evaluation of the received rewards. An idiosyncratic finding was that neurons showing negative correlations represented reward values in the near future (high discounting), while neurons showing positive correlations represented reward values not only in the near future, but also in the far future (low discounting). These findings provide a new insight that long-term value signals are embedded in two subsets of striatal neurons as high and low discounting of multiple future rewards.


2018 ◽  
Author(s):  
Kuan-Ming Lu ◽  
Shih-Yun Chen ◽  
Hsin-An Ko ◽  
Ting-Hao Huang ◽  
Janice Hsin-Jou Hao ◽  
...  

ABSTRACTThe division of the striatum into dorsal and ventral districts is of central clinical importance. The dorsal striatum is differentially affected in Huntington’s disease, dopamine in the ventral striatum is differentially spared in Parkinson’s disease, and human brain imaging studies implicate the ventral striatum in addictive disorders. If fits that the dorsal striatum contains the cells of origin of the direct and indirect basal ganglia pathways for motor control. The ventral striatum is a node in neural circuits related to motivation and affect. Despite these striking neurobiologic contrasts, there is almost no information about how the dorsal and ventral divisions of the striatum are set up during development. Here, we demonstrate that interactions between the two key transcription factors Nolz-1 and Dlx1/2 control the migratory paths of developing striatal neurons to the dorsal or ventral striatum. Moreover, these same transcription factors control the cell identity of striatal projection neurons in both the dorsal and ventral striatum including the cell origin of the direct and indirect pathways. We show that Nolz-1 suppresses Dlx1/2 expression. Deletion of Nolz-1 or over-expression of Dlx1/2 can produce a striatal phenotype characterized by withered dorsal striatum and a swollen ventral striatum, and that we can rescue this phenotype by manipulating the interactions between Nolz-1 and Dlx1/2 transcription factors. This evidence suggests that the fundamental basis for divisions of the striatum known to be differentially vulnerable at maturity is already encoded by the time embryonic striatal neurons begin their migrations into the developing striatum.


2020 ◽  
Vol 117 (13) ◽  
pp. 7418-7429 ◽  
Author(s):  
Shih-Yun Chen ◽  
Kuan-Ming Lu ◽  
Hsin-An Ko ◽  
Ting-Hao Huang ◽  
Janice Hsin-Jou Hao ◽  
...  

The striatal complex of basal ganglia comprises two functionally distinct districts. The dorsal district controls motor and cognitive functions. The ventral district regulates the limbic function of motivation, reward, and emotion. The dorsoventral parcellation of the striatum also is of clinical importance as differential striatal pathophysiologies occur in Huntington’s disease, Parkinson’s disease, and drug addiction disorders. Despite these striking neurobiologic contrasts, it is largely unknown how the dorsal and ventral divisions of the striatum are set up. Here, we demonstrate that interactions between the two key transcription factors Nolz-1 and Dlx1/2 control the migratory paths of striatal neurons to the dorsal or ventral striatum. Moreover, these same transcription factors control the cell identity of striatal projection neurons in both the dorsal and the ventral striata including the D1-direct and D2-indirect pathways. We show that Nolz-1, through the I12b enhancer, represses Dlx1/2, allowing normal migration of striatal neurons to dorsal and ventral locations. We demonstrate that deletion, up-regulation, and down-regulation of Nolz-1 and Dlx1/2 can produce a striatal phenotype characterized by a withered dorsal striatum and an enlarged ventral striatum and that we can rescue this phenotype by manipulating the interactions between Nolz-1 and Dlx1/2 transcription factors. Our study indicates that the two-tier system of striatal complex is built by coupling of cell-type identity and migration and suggests that the fundamental basis for divisions of the striatum known to be differentially vulnerable at maturity is already encoded by the time embryonic striatal neurons begin their migrations into developing striata.


2011 ◽  
Vol 106 (6) ◽  
pp. 3019-3034 ◽  
Author(s):  
Shengyuan Ding ◽  
Wei Wei ◽  
Fu-Ming Zhou

GABA projection neurons (GABA neurons) in the substantia nigra pars reticulata (SNr) and dopamine projection neurons (DA neurons) in substantia nigra pars compacta (SNc) have strikingly different firing properties. SNc DA neurons fire low-frequency, long-duration spikes, whereas SNr GABA neurons fire high-frequency, short-duration spikes. Since voltage-activated sodium (NaV) channels are critical to spike generation, the different firing properties raise the possibility that, compared with DA neurons, NaV channels in SNr GABA neurons have higher density, faster kinetics, and less cumulative inactivation. Our quantitative RT-PCR analysis on immunohistochemically identified nigral neurons indicated that mRNAs for pore-forming NaV1.1 and NaV1.6 subunits and regulatory NaVβ1 and Navβ4 subunits are more abundant in SNr GABA neurons than SNc DA neurons. These α-subunits and β-subunits are key subunits for forming NaV channels conducting the transient NaV current ( INaT), persistent Na current ( INaP), and resurgent Na current ( INaR). Nucleated patch-clamp recordings showed that INaT had a higher density, a steeper voltage-dependent activation, and a faster deactivation in SNr GABA neurons than in SNc DA neurons. INaT also recovered more quickly from inactivation and had less cumulative inactivation in SNr GABA neurons than in SNc DA neurons. Furthermore, compared with nigral DA neurons, SNr GABA neurons had a larger INaR and INaP. Blockade of INaP induced a larger hyperpolarization in SNr GABA neurons than in SNc DA neurons. Taken together, these results indicate that NaV channels expressed in fast-spiking SNr GABA neurons and slow-spiking SNc DA neurons are tailored to support their different spiking capabilities.


Author(s):  
Harry S. Xenias ◽  
Chuyu Chen ◽  
Shuo Kang ◽  
Suraj Cherian ◽  
Xiaolei Situ ◽  
...  

AbstractLRRK2 mutations are associated with both familial and sporadic forms of Parkinson’s disease (PD). Convergent evidence suggests that LRRK2 plays critical roles in regulating striatal function. Here, by using knock-in mouse lines that express the two most common LRRK2 pathogenic mutations—G2019S and R1441C—we investigated how pathogenic LRRK2 mutations altered striatal physiology. We found that R1441C mice displayed a reduced nigrostriatal dopamine release and hypoexcitability in indirect-pathway striatal projection neurons. These alterations were associated with an impaired striatal-dependent motor learning. This deficit in motor learning was rescued following the subchronic administration of the LRRK2 kinase inhibitor Mli-2. In contrast, though a decreased release of dopamine was observed in the G2019S knock-in mice no concomitant cellular and behavioral alterations were found. In summary, our data argue that the impact of LRRK2 mutations cannot be simply generalized. Our findings offer mechanistic insights for devising treatment strategies for PD patients.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Maria-Daniela Cirnaru ◽  
Sicheng Song ◽  
Kizito-Tshitoko Tshilenge ◽  
Chuhyon Corwin ◽  
Justyna Mleczko ◽  
...  

Many diseases are linked to dysregulation of the striatum. Striatal function depends on neuronal compartmentation into striosomes and matrix. Striatal projection neurons are GABAergic medium spiny neurons (MSNs), subtyped by selective expression of receptors, neuropeptides, and other gene families. Neurogenesis of the striosome and matrix occurs in separate waves, but the factors regulating compartmentation and neuronal differentiation are largely unidentified. We performed RNA- and ATAC-seq on sorted striosome and matrix cells at postnatal day 3, using the Nr4a1-EGFP striosome reporter mouse. Focusing on the striosome, we validated the localization and/or role of Irx1, Foxf2, Olig2, and Stat1/2 in the developing striosome and the in vivo enhancer function of a striosome-specific open chromatin region 4.4 Kb downstream of Olig2. These data provide novel tools to dissect and manipulate the networks regulating MSN compartmentation and differentiation, including in human iPSC-derived striatal neurons for disease modeling and drug discovery.


2020 ◽  
Author(s):  
Christopher Dorsett ◽  
Benjamin Philpot ◽  
Spencer LaVere Smith ◽  
Ikuko T. Smith

AbstractExcitatory inputs arriving at the dendrites of a neuron can engage active mechanisms that nonlinearly amplify the depolarizing currents. Interneuron-mediated inhibition can modulate this active process, in a subtype-dependent manner. For example, dendrite-targeting inhibition is hypothesized to increase the amplitude of synaptic input required to activate voltage-dependent nonlinear synaptic integration. To examine how inhibition influences active synaptic integration, we optogenetically manipulated the activity of two different subtypes of interneurons: dendrite-targeting somatostatin-expressing (SOM) and perisomatic-targeting parvalbumin-expressing (PV) interneurons. In acute slices of mouse primary visual cortex, electrical stimulation evoked nonlinear synaptic integration that depended on N-methyl-D-aspartate (NMDA) receptors. Optogenetic activation of SOM neurons in conjunction with electrical stimulation resulted in predominantly divisive inhibitory gain control, reducing the magnitude of the nonlinear response without affecting its threshold. PV activation, on the other hand, had a minimal effect on dendritic nonlinearities, resulting in a small subtractive effect. Furthermore, we found that mutual inhibition among SOM interneurons was strong and more prevalent than previously thought, while mutual inhibition among PV interneurons was minimal. These results challenge previous models of inhibitory modulation of active synaptic integration. The major effect of SOM inhibition is not a shift in threshold for activation of nonlinear integration, but rather a decrease the amplitude of the nonlinear response.


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