Biology subjects

Kolpakova, J.

Publications and source records attributed to Kolpakova, J..

3 recordsLinked to original sources

bioRxiv2022

Binge alcohol drinking alters the differential control of cholinergic interneurons over nucleus accumbens D1 and D2 medium spiny neurons

BackgroundVentral striatal cholinergic interneurons (ChIs) play a central role in basal ganglia function by regulating associative learning and reward processing. In the nucleus accumbens (NAc), ChIs regulate glutamatergic, dopaminergic, and GABAergic neurotransmission. However, it is unclear how ChIs orchestrate the control of these neurotransmitters to determine the excitability of medium spiny neurons (MSNs) expressing either dopamine D1 or D2 receptors. Additionally, the effects of binge alcohol drinking on ChIs-mediated modulation of glutamatergic synaptic transmission in NAc MSNs are also undefined. MethodsWe optogenetically stimulated ChIs while recording evoked and spontaneous excitatory postsynaptic currents (sEPSCs) in D1- and D2-MSN of ChAT.ChR2.eYFPxDrd1.tdtomato mice. To determine the effect of ChIs on mouse behavior and alcohol consumption, we implanted ChAT.ChR2.eYFP mice with fiber optic cannulas and stimulated ChIs while mice were allowed to drink 20% alcohol using the binge alcohol drinking- in-the-dark (DID) paradigm. ResultsWe demonstrated that NAc ChIs decrease the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in both D1- and D2-MSNs. While inhibition of D1-MSNs glutamate release by ChIs depends on dopamine release, that of D2-MSNs results from a direct interactions between ChIs and glutamatergic terminals. Interestingly, after two weeks of binge alcohol drinking, the effect of ChIs stimulation on glutamate release was reversed in D1-MSNs, while its effect on D2-MSNs remained unchanged. Finally, in vivo optogenetic stimulation of NAc ChIs significantly increased alcohol consumption. ConclusionsThese results identify ChIs as a key target for the regulation of NAc circuitry and as a potential treatment of alcohol addiction.

neuroscience↗

bioRxiv2022

EPHierStats: a statistical tool to model the hierarchical relationships in electrophysiological data

Electrophysiological datasets are typically analyzed under the assumption that repeated measurements of the same unit of analysis (i.e. neuron or animal) can be treated as statistically independent. Recently, this assumption has been questioned and our data confirms and quantifies this skepticism using ex vivo slice recordings of synaptic currents in D1R+ medium spiny neurons in the nucleus accumbens. We therefore present EPHierStats as a statistical framework to analyze electrophysiological datasets with large numbers of measurements (>100) per unit of analysis. This novel analysis framework enables encoding of the full hierarchical relationships between measurements in a mixed-effects general linear model while also analyzing the distribution of values in assessed variables. Our method can easily be adapted to analyze a wide range of repeated-measures electrophysiological experiments. Implementation of the EPHierStats tool will aid the adaption of modern statistical approaches that prevent pseudoreplication and its associated false discovery rate while enabling statistical assessments of the complex relationships inherent to the field of neuroscience.

neuroscience↗

bioRxiv2019

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

Dopamine (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.

neuroscience↗