scholarly journals Conditional, inducible gene silencing in dopamine neurons reveals a sex-specific role for Rit2 GTPase in acute cocaine response and striatal function

2019 ◽  
Author(s):  
Carolyn G. Sweeney ◽  
Patrick J. Kearney ◽  
Rita R. Fagan ◽  
Lindsey A. Smith ◽  
Nicholas C. Bolden ◽  
...  
Keyword(s):  
Ventral Striatum ◽  
Surface Expression ◽  
Dopamine Neurons ◽  
Medium Spiny Neurons ◽  
Protein Levels ◽  
Spiny Neurons ◽  
Males And Females ◽  
Striatal Function ◽  
Inducible Gene

AbstractDopamine (DA) signaling is critical for movement, motivation, and addictive behavior. The neuronal GTPase, Rit2, is enriched in DA neurons (DANs), binds directly to the DA transporter (DAT), and is implicated in several DA-related neuropsychiatric disorders. However, it remains unknown whether Rit2 plays a role in either DAergic signaling and/or DA-dependent behaviors. Here, we leveraged the TET-OFF system to conditionally silence Rit2 in Pitx3IRES2-tTA mouse DANs. Following DAergic Rit2 knockdown (Rit2-KD), mice displayed an anxiolytic phenotype, with no change in baseline locomotion. Further, males exhibited increased acute cocaine sensitivity, whereas DAergic Rit2-KD suppressed acute cocaine sensitivity in females. DAergic Rit2-KD did not affect presynaptic TH and DAT protein levels in females, nor was TH was affected in males; however, DAT was significantly diminished in males. Paradoxically, despite decreased DAT levels in males, striatal DA uptake was enhanced, but was not due to enhanced DAT surface expression in either dorsal or ventral striatum. Finally, patch recordings in nucleus accumbens (NAcc) medium spiny neurons (MSNs) revealed reciprocal changes in spontaneous EPSP (sEPSP) frequency in male and female D1+ and D2+ MSNs following DAergic Rit2-KD. In males, sEPSP frequency was decreased in D1+, but not D2+, MSNs, whereas in females sEPSP frequency decreased in D2+, but not D1+, MSNs. Moreover, DAergic Rit2-KD abolished the ability of cocaine to reduce sEPSP frequency in D1+, but not D2+, male MSNs. Taken together, our studies are among the first to acheive AAV-mediated, conditional and inducible DAergic knockdown in vivo. Importantly, our results provide the first evidence that DAergic Rit2 expression differentially impacts striatal function and DA-dependent behaviors in males and females.

Brain-derived neurotrophic factor regulates maturation of the DARPP-32 phenotype in striatal medium spiny neurons: studies in vivo and in vitro

Neuroscience ◽  
1997 ◽  
Vol 79 (2) ◽  
pp. 509-516 ◽  
Author(s):  
S Ivkovic ◽  
O Polonskaia ◽  
I Fariñas ◽  
M.E Ehrlich
Keyword(s):  
Neurotrophic Factor ◽  
Brain Derived Neurotrophic Factor ◽  
Medium Spiny Neurons ◽  
Spiny Neurons

scholarly journals Binge Alcohol Drinking Alters Synaptic Processing of Executive and Emotional Information in Core Nucleus Accumbens Medium Spiny Neurons

2021 ◽  
Vol 15 ◽  
Author(s):  
Jenya Kolpakova ◽  
Vincent van der Vinne ◽  
Pablo Giménez-Gómez ◽  
Timmy Le ◽  
In-Jee You ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Alcohol Drinking ◽  
Drugs Of Abuse ◽  
Alcohol Exposure ◽  
Medium Spiny Neurons ◽  
Dependent Manner ◽  
Emotional Information ◽  
Core Nucleus ◽  
Spiny Neurons

The nucleus accumbens (NAc) is a forebrain region mediating the positive-reinforcing properties of drugs of abuse, including alcohol. It receives glutamatergic projections from multiple forebrain and limbic regions such as the prefrontal cortex (PFCx) and basolateral amygdala (BLA), respectively. However, it is unknown how NAc medium spiny neurons (MSNs) integrate PFCx and BLA inputs, and how this integration is affected by alcohol exposure. Because progress has been hampered by the inability to independently stimulate different pathways, we implemented a dual wavelength optogenetic approach to selectively and independently stimulate PFCx and BLA NAc inputs within the same brain slice. This approach functionally demonstrates that PFCx and BLA inputs synapse onto the same MSNs where they reciprocally inhibit each other pre-synaptically in a strict time-dependent manner. In alcohol-naïve mice, this temporal gating of BLA-inputs by PFCx afferents is stronger than the reverse, revealing that MSNs prioritize high-order executive processes information from the PFCx. Importantly, binge alcohol drinking alters this reciprocal inhibition by unilaterally strengthening BLA inhibition of PFCx inputs. In line with this observation, we demonstrate that in vivo optogenetic stimulation of the BLA, but not PFCx, blocks binge alcohol drinking escalation in mice. Overall, our results identify NAc MSNs as a key integrator of executive and emotional information and show that this integration is dysregulated during binge alcohol drinking.

scholarly journals Medium spiny neurons activity reveals the discrete segregation of mouse dorsal striatum

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Javier Alegre-Cortés ◽  
María Sáez ◽  
Roberto Montanari ◽  
Ramon Reig
Keyword(s):  
Dorsal Striatum ◽  
Medium Spiny Neurons ◽  
Extracellular Recordings ◽  
Electrophysiological Properties ◽  
Spiny Neurons ◽  
Behavioral Studies ◽  
Sensory Activity ◽  
Fast Oscillations ◽  
Anatomical Evidence

Behavioral studies differentiate the rodent dorsal striatum (DS) into lateral and medial regions; however, anatomical evidence suggests that it is a unified structure. To understand striatal dynamics and basal ganglia functions, it is essential to clarify the circuitry that supports this behavioral-based segregation. Here, we show that the mouse DS is made of two non-overlapping functional circuits divided by a boundary. Combining in vivo optopatch-clamp and extracellular recordings of spontaneous and evoked sensory activity, we demonstrate different coupling of lateral and medial striatum to the cortex together with an independent integration of the spontaneous activity, due to particular corticostriatal connectivity and local attributes of each region. Additionally, we show differences in slow and fast oscillations and in the electrophysiological properties between striatonigral and striatopallidal neurons. In summary, these results demonstrate that the rodent DS is segregated in two neuronal circuits, in homology with the caudate and putamen nuclei of primates.

scholarly journals Injection with Toxoplasma gondii protein affects neuron health and survival

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Oscar A Mendez ◽  
Emiliano Flores Machado ◽  
Jing Lu ◽  
Anita Koshy
Keyword(s):  
Toxoplasma Gondii ◽  
Single Neuron ◽  
Latent Infection ◽  
Medium Spiny Neurons ◽  
Patch Clamping ◽  
Spiny Neurons ◽  
The Brain ◽  
Mapping Program

Toxoplasma gondii is an intracellular parasite that causes a long-term latent infection of neurons. Using a custom MATLAB-based mapping program in combination with a mouse model that allows us to permanently mark neurons injected with parasite proteins, we found that Toxoplasma-injected neurons (TINs) are heterogeneously distributed in the brain, primarily localizing to the cortex followed by the striatum. In addition, we determined that cortical TINs are commonly (>50%) excitatory neurons (FoxP2+) and that striatal TINs are often (>65%) medium spiny neurons (MSNs) (FoxP2+). By performing single neuron patch-clamping on striatal TINs and neighboring uninfected MSNs, we discovered that TINs have highly aberrant electrophysiology. As approximately 90% of TINs will die by 8 weeks post-infection, this abnormal physiology suggests that injection with Toxoplasma protein— either directly or indirectly— affects neuronal health and survival. Collectively, these data offer the first insights into which neurons interact with Toxoplasma and how these interactions alter neuron physiology in vivo.

scholarly journals Neuronal signature of an antipsychotic response

2020 ◽  
Author(s):  
Jeffrey Parrilla-Carrero ◽  
Anna Kruyer ◽  
Reda M. Chalhoub ◽  
Courtney Powell ◽  
Shanna Resendez ◽  
...  
Keyword(s):  
D2 Receptor ◽  
Symptom Improvement ◽  
Medium Spiny Neurons ◽  
Principal Mechanism ◽  
Spiny Neurons ◽  
Nmda Channel ◽  
Resolution Imaging ◽  
The Impact ◽  
The Brain

Abstract D2 receptor blockade has been cited as a principal mechanism of action of all antipsychotic medications, but is poorly predictive of symptom improvement or neurophysiological responses recorded using human brain imaging. A potential hurdle in interpreting such human imaging studies arises from the inability to distinguish activity within neuronal subcircuits. We used single cell resolution imaging to record activity in distinct populations of medium spiny neurons in vivo within the mouse ventral striatum, a structure associated with schizophrenia symptoms and antipsychotic therapeutic efficacy. While we expected the antipsychotic haloperidol to excite D2 receptor expressing neurons, we report a strong cellular depression mediated by the hypofunctional NMDA channel, which may be mediated in part by the action of haloperidol on the sigma1 receptor. Altogether, the impact of haloperidol on Ca2+ events in D2 receptor expressing neurons predicted psychomotor inhibition. Our results elucidate mechanisms by which antipsychotics act rapidly in the brain to impact psychomotor outputs.

scholarly journals Conditional, inducible gene silencing in dopamine neurons reveals a sex-specific role for Rit2 GTPase in acute cocaine response and striatal function

2019 ◽  
Vol 45 (2) ◽  
pp. 384-393 ◽  
Author(s):  
Carolyn G. Sweeney ◽  
Patrick J. Kearney ◽  
Rita R. Fagan ◽  
Lindsey A. Smith ◽  
Nicholas C. Bolden ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Specific Role ◽  
Dopamine Neurons ◽  
Striatal Function ◽  
Inducible Gene

Kv1.2-Containing K+ Channels Regulate Subthreshold Excitability of Striatal Medium Spiny Neurons

2004 ◽  
Vol 91 (3) ◽  
pp. 1337-1349 ◽  
Author(s):  
Weixing Shen ◽  
Salvador Hernandez-Lopez ◽  
Tatiana Tkatch ◽  
Joshua E. Held ◽  
D. James Surmeier
Keyword(s):  
State Transitions ◽  
Medium Spiny Neurons ◽  
Rt Pcr ◽  
High Affinity ◽  
Spiny Neurons ◽  
Low Threshold ◽  
Rapid Activation ◽  
Repetitive Discharge ◽  
Spike Latency

A slowly inactivating, low-threshold K+ current has been implicated in the regulation of state transitions and repetitive activity in striatal medium spiny neurons. However, the molecular identity of the channels underlying this current and their biophysical properties remain to be clearly determined. Because previous work had suggested this current arose from Kv1 family channels, high-affinity toxins for this family were tested for their ability to block whole cell K+ currents activated by depolarization of acutely isolated neurons. α-Dendrotoxin, which blocks channels containing Kv1.1, Kv1.2, or Kv1.6 subunits, decreased currents evoked by depolarization. Three other Kv1 family toxins that lack a high affinity for Kv1.2 subunits, r-agitoxin-2, dendrotoxin-K, and r-margatoxin, failed to significantly reduce currents, implicating channels with Kv1.2 subunits. RT-PCR results confirmed the expression of Kv1.2 mRNA in identified medium spiny neurons. Currents attributable to Kv1.2 channels activated rapidly, inactivated slowly, and recovered from inactivation slowly. In the subthreshold range (ca. -60 mV), these currents accounted for as much as 50% of the depolarization-activated K+ current. Moreover, their rapid activation and relatively slow deactivation suggested that they contribute to spike afterpotentials regulating repetitive discharge. This inference was confirmed in current-clamp recordings from medium spiny neurons in the slice preparation where Kv1.2 blockade reduced first-spike latency and increased discharge frequency evoked from hyperpolarized membrane potentials resembling the “down-state” found in vivo. These studies establish a clear functional role for somato-dendritic Kv1.2 channels in the regulation of state transitions and repetitive discharge in striatal medium spiny neurons.

scholarly journals Arrest of G1-S Progression by the p53-Inducible Gene PC3 Is Rb Dependent and Relies on the Inhibition of Cyclin D1 Transcription

2000 ◽  
Vol 20 (5) ◽  
pp. 1797-1815 ◽  
Author(s):  
Daniele Guardavaccaro ◽  
Giuseppina Corrente ◽  
Francesca Covone ◽  
Laura Micheli ◽  
Igea D'Agnano ◽  
...  
Keyword(s):  
Cyclin D1 ◽  
D1 Protein ◽  
Down Regulation ◽  
Inhibition Of Proliferation ◽  
Protein Levels ◽  
Growth Inhibitory ◽  
Cyclin D1 Protein ◽  
Cdk4 Activity ◽  
Inducible Gene

ABSTRACT The p53-inducible gene PC3 (TIS21, BTG2) is endowed with antiproliferative activity. Here we report that expression ofPC3 in cycling cells induced accumulation of hypophosphorylated, growth-inhibitory forms of pRb and led to G1 arrest. This latter was not observed in cells with genetic disruption of the Rb gene, indicating that thePC3-mediated G1 arrest was Rb dependent. Furthermore, (i) the arrest of G1-S transition exerted by PC3 was completely rescued by coexpression of cyclin D1 but not by that of cyclin A or E; (ii) expression of PC3 caused a significant down-regulation of cyclin D1 protein levels, also in Rb-defective cells, accompanied by inhibition of CDK4 activity in vivo; and (iii) the removal from the PC3 molecule of residues 50 to 68, a conserved domain of the PC3/BTG/Tob gene family, which we term GR, led to a loss of the inhibition of proliferation as well as of the down-regulation of cyclin D1 levels. These data point to cyclin D1 down-regulation as the main factor responsible for the growth inhibition by PC3. Such an effect was associated with a decrease of cyclin D1 transcript and of cyclin D1 promoter activity, whereas no effect of PC3 was observed on cyclin D1 protein stability. Taken together, these findings indicate that PC3 impairs G1-S transition by inhibiting pRb function in consequence of a reduction of cyclin D1 levels and that PC3 acts, either directly or indirectly, as a transcriptional regulator of cyclin D1.

scholarly journals Transitions between sleep and feeding states in rat ventral striatum neurons

2012 ◽  
Vol 108 (6) ◽  
pp. 1739-1751 ◽  
Author(s):  
Luis A. Tellez ◽  
Isaac O. Perez ◽  
Sidney A. Simon ◽  
Ranier Gutierrez
Keyword(s):  
Neural Networks ◽  
Ventral Striatum ◽  
Cell Types ◽  
Projection Neurons ◽  
Inhibitory Interneurons ◽  
Medium Spiny Neurons ◽  
Spiny Neurons ◽  
Fast Spiking ◽  
First Time

Neurons in the nucleus accumbens (NAc) have been shown to participate in several behavioral states, including feeding and sleep. However, it is not known if the same neuron participates in both states and, if so, how similar are the responses. In addition, since the NAc contains several cell types, it is not known if each type participates in the transitions associated with feeding and sleep. Such knowledge is important for understanding the interaction between two different neural networks. For these reasons we recorded ensembles of NAc neurons while individual rats volitionally transitioned between the following states: awake and goal directed, feeding, quiet-awake, and sleeping. We found that during both feeding and sleep states, the same neurons could increase their activity (be activated) or decrease their activity (be inactivated) by feeding and/or during sleep, thus indicating that the vast majority of NAc neurons integrate sleep and feeding signals arising from spatially distinct neural networks. In contrast, a smaller population was modulated by only one of the states. For the majority of neurons in either state, we found that when one population was excited, the other was inhibited, suggesting that they act as a local circuit. Classification of neurons into putative interneurons [fast-spiking interneurons (pFSI) and choline acetyltransferase interneurons (pChAT)] and projection medium spiny neurons (pMSN) showed that all three types are modulated by transitions to and from feeding and sleep states. These results show, for the first time, that in the NAc, those putative inhibitory interneurons respond similarly to pMSN projection neurons and demonstrate interactions between NAc networks involved in sleep and feeding.

scholarly journals c-Myc mediates pre-TCR-induced proliferation but not developmental progression

Blood ◽  
2006 ◽  
Vol 108 (8) ◽  
pp. 2669-2677 ◽  
Author(s):  
Marei Dose ◽  
Irum Khan ◽  
Zhuyan Guo ◽  
Damian Kovalovsky ◽  
Andreas Krueger ◽  
...  
Keyword(s):  
Cell Receptor ◽  
Surface Expression ◽  
Double Negative ◽  
Tcr Signaling ◽  
Double Positive ◽  
Protein Levels ◽  
Developmental Progression ◽  
Severe Reduction

AbstractConstitutive and cell-autonomous signals emanating from the pre-T-cell receptor (pre-TCR) promote proliferation, survival and differentiation of immature thymocytes. We show here that induction of pre-TCR signaling resulted in rapid elevation of c-Myc protein levels. Cre-mediated thymocyte-specific ablation of c-Myc in CD25+CD44- thymocytes reduced proliferation and cell growth at the pre-TCR checkpoint, resulting in thymic hypocellularity and a severe reduction in CD4+CD8+ thymocytes. In contrast, c-Myc deficiency did not inhibit pre-TCR-mediated differentiation or survival. Myc-/- double-negative (DN) 3 cells progressed to the double-positive (DP) stage and up-regulated TCRαβ surface expression in the absence of cell proliferation, in vivo as well as in vitro. These observations indicate that distinct signals downstream of the pre-TCR are responsible for proliferation versus differentiation, and demonstrate that c-Myc is only required for pre-TCR-induced proliferation but is dispensable for developmental progression from the DN to the DP stage.

Sign in / Sign up

Export Citation Format

Share Document