scholarly journals Plasticity in striatal dopamine release is governed by release-independent depression and the dopamine transporter

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mark D. Condon ◽  
Nicola J. Platt ◽  
Yan-Feng Zhang ◽  
Bradley M. Roberts ◽  
Michael A. Clements ◽  
...  

Abstract Mesostriatal dopaminergic neurons possess extensively branched axonal arbours. Whether action potentials are converted to dopamine output in the striatum will be influenced dynamically and critically by axonal properties and mechanisms that are poorly understood. Here, we address the roles for mechanisms governing release probability and axonal activity in determining short‐term plasticity of dopamine release, using fast‐scan cyclic voltammetry in the ex vivo mouse striatum. We show that brief short‐term facilitation and longer short term depression are only weakly dependent on the level of initial release, i.e. are release insensitive. Rather, short-term plasticity is strongly determined by mechanisms which govern axonal activation, including K+‐gated excitability and the dopamine transporter, particularly in the dorsal striatum. We identify the dopamine transporter as a master regulator of dopamine short‐term plasticity, governing the balance between release‐dependent and independent mechanisms that also show region‐specific gating.

2018 ◽  
Author(s):  
Mark D. Condon ◽  
Nicola J. Platt ◽  
Yan-Feng Zhang ◽  
Bradley M. Roberts ◽  
Michael A. Clements ◽  
...  

AbstractMesostriatal DA neurons possess extensively branched axonal arbours. Whether action potentials are converted to DA output in striatum will be influenced dynamically and critically by axonal properties and mechanisms that are poorly understood. We addressed the roles for mechanisms governing release probability and axonal activity in determining short-term plasticity of DA release, using fast-scan cyclic voltammetry in ex vivo mouse striatum. Brief short-term facilitation (STF) and longer short-term depression (STD) were only weakly dependent on the level of initial release, i.e. were release-insensitive. Rather, short-term plasticity was strongly determined by mechanisms which governed axonal activation, including K+-gated excitability and the dopamine transporter (DAT), particularly in dorsal striatum. We identify the DAT as a master regulator of DA short-term plasticity, governing the balance between release-dependent and independent mechanisms that also show region-specific gating.Key FindingsShort-term plasticity in dopamine release is only weakly governed by initial releaseShort-term depression is strongly dependent on axonal excitability and activationThe dopamine transporter controls short-term plasticity and drives short-term depressionDopamine transporters govern the balance between release-dependent and -independent mechanisms


Author(s):  
Andrea Jaquins-Gerstl ◽  
Kathryn M. Nesbitt ◽  
Adrian C. Michael

AbstractThe neurochemical transmitter dopamine (DA) is implicated in a number of diseases states, including Parkinson’s disease, schizophrenia, and drug abuse. DA terminal fields in the dorsal striatum and core region of the nucleus accumbens in the rat brain are organized as heterogeneous domains exhibiting fast and slow kinetic of DA release. The rates of dopamine release are significantly and substantially faster in the fast domains relative to the slow domains. The striatum is composed of a mosaic of spatial compartments known as the striosomes (patches) and the matrix. Extensive literature exists on the spatial organization of the patch and matrix compartments and their functions. However, little is known about these compartments as they relate to fast and slow kinetic DA domains observed by fast scan cyclic voltammetry (FSCV). Thus, we combined high spatial resolution of FSCV with detailed immunohistochemical analysis of these architectural compartments (patch and matrix) using fluorescence microscopy. Our findings demonstrated a direct correlation between patch compartments with fast domain DA kinetics and matrix compartments to slow domain DA kinetics. We also investigated the kinetic domains in two very distinct sub-regions in the striatum, the lateral dorsal striatum (LDS) and the medial dorsal striatum (MDS). The lateral dorsal striatum as opposed to the medial dorsal striatum is mainly governed by fast kinetic DA domains. These finding are highly relevant as they may hold key promise in unraveling the fast and slow kinetic DA domains and their physiological significance. Graphical abstract


2001 ◽  
Vol 85 (5) ◽  
pp. 2088-2099 ◽  
Author(s):  
John S. Fitzpatrick ◽  
Garnik Akopian ◽  
John P. Walsh

Two forms of short-term plasticity at inhibitory synapses were investigated in adult rat striatal brain slices using intracellular recordings. Intrastriatal stimulation in the presence of the ionotropic glutamate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (20 μM) andd,l-2-amino-5-phosphonovaleric acid (50 μM) produced an inhibitory postsynaptic potential (IPSP) that reversed polarity at −76 ± 1 (SE) mV and was sensitive to bicuculline (30 μM). The IPSP rectified at hyperpolarized membrane potentials due in part to activation of K+ channels. The IPSP exhibited two forms of short-term plasticity, paired-pulse depression (PPD) and synaptic augmentation. PPD lasted for several seconds and was greatest at interstimulus intervals (ISIs) of several hundred milliseconds, reducing the IPSP to 80 ± 2% of its control amplitude at an ISI of 200 ms. Augmentation of the IPSP, elicited by a conditioning train of 15 stimuli applied at 20 Hz, was 119 ± 1% of control when sampled 2 s after the conditioning train. Augmentation decayed with a time constant of 10 s. We tested if PPD and augmentation modify the ability of the IPSP to prevent the generation of action potentials. A train of action potentials triggered by a depolarizing current injection of constant amplitude could be interrupted by stimulation of an IPSP. If this IPSP was the second in a pair of IPSPs, it was less effective in blocking spikes due to PPD. By contrast, augmented IPSPs were more effective in blocking spikes. The same results were achieved when action potentials were triggered by a depolarizing current injection of varying amplitude, a manipulation that produces nearly identical spike times from trial to trial and approximates the in vivo behavior of these neurons. These results demonstrate that short-term plasticity of inhibition can modify the output of the striatum and thus may be an important component of information processing during behaviors that involve the striatum.


2019 ◽  
Vol 10 (8) ◽  
pp. 3419-3426 ◽  
Author(s):  
Katherine R. Brimblecombe ◽  
Stefania Vietti-Michelina ◽  
Nicola J. Platt ◽  
Rahel Kastli ◽  
Ahmad Hnieno ◽  
...  

Author(s):  
Paul J Banks ◽  
E Clea Warburton ◽  
Zafar I Bashir

AbstractThe nucleus reuniens of the thalamus (NRe) is reciprocally connected to a range of higher order cortices including hippocampus (HPC) and medial prefrontal cortex (mPFC). The physiological function of NRe is well predicted by requirement for interactions between mPFC and HPC, including associative recognition memory, spatial navigation and working memory. Although anatomical and electrophysiological evidence suggests NRe makes excitatory synapses in mPFC there is little data on the physiological properties of these projections, or whether NRe and HPC target overlapping cell populations and, if so, how they interact. We demonstrate in ex vivo mPFC slices that NRe and HPC afferent inputs converge onto more than two-thirds of layer 5 pyramidal neurons, show that NRe, but not HPC, undergoes marked short-term plasticity at theta, and that HPC, but not NRe, afferents are subject to neuromodulation by acetylcholine acting via muscarinic receptor M2. Finally, we demonstrate that pairing HPC followed by NRe (but not pairing NRe followed by HPC) at theta frequency induces associative, NMDA receptor dependent synaptic plasticity in both inputs to mPFC. These data provide vital physiological phenotypes of the synapses of this circuit and provide a novel mechanism for HPC-NRe-mPFC encoding.


2020 ◽  
Vol 46 (2) ◽  
pp. 394-403
Author(s):  
Fabien Naneix ◽  
Kate Z. Peters ◽  
Andrew M. J. Young ◽  
James E. McCutcheon

AbstractDespite the essential role of protein intake for health and development, very little is known about the impact of protein restriction on neurobiological functions, especially at different stages of the lifespan. The dopamine system is a central actor in the integration of food-related processes and is influenced by physiological state and food-related signals. Moreover, it is highly sensitive to dietary effects during early life periods such as adolescence due to its late maturation. In the present study, we investigated the impact of protein restriction either during adolescence or adulthood on the function of the mesolimbic (nucleus accumbens) and nigrostriatal (dorsal striatum) dopamine pathways using fast-scan cyclic voltammetry in rat brain slices. In the nucleus accumbens, protein restriction in adults increased dopamine release in response to low and high frequency trains of stimulation (1–20 Hz). By contrast, protein restriction during adolescence decreased nucleus accumbens dopamine release. In the dorsal striatum, protein restriction at adulthood has no impact on dopamine release but the same diet during adolescence induced a frequency-dependent increase in stimulated dopamine release. Taken together, our results highlight the sensitivity of the different dopamine pathways to the effect of protein restriction, as well as their vulnerability to deleterious diet effects at different life stages.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. A. Nadel ◽  
S. S. Pawelko ◽  
J. R. Scott ◽  
R. McLaughlin ◽  
M. Fox ◽  
...  

AbstractHabits are inflexible behaviors that develop after extensive repetition, and overreliance on habits is a hallmark of many pathological states. The striatum is involved in the transition from flexible to inflexible responding, and interspersed throughout the striatum are patches, or striosomes, which make up ~15% of the volume of the striatum relative to the surrounding matrix compartment. Previous studies have suggested that patches are necessary for normal habit formation, but it remains unknown exactly how patches contribute to habit formation and expression. Here, using optogenetics, we stimulated striatal patches in Sepw1-NP67 mice during variable interval training (VI60), which is used to establish habitual responding. We found that activation of patches at reward retrieval resulted in elevated responding during VI60 training by modifying the pattern of head entry and pressing. Further, this optogenetic manipulation reduced subsequent responding following reinforcer devaluation, suggesting modified habit formation. However, patch stimulation did not generally increase extinction rates during a subsequent extinction probe, but did result in a small ‘extinction burst’, further suggesting goal-directed behavior. On the other hand, this manipulation had no effect in omission trials, where mice had to withhold responses to obtain rewards. Finally, we utilized fast-scan cyclic voltammetry to investigate how patch activation modifies evoked striatal dopamine release and found that optogenetic activation of patch projections to the substantia nigra pars compacta (SNc) is sufficient to suppress dopamine release in the dorsal striatum. Overall, this work provides novel insight into the role of the patch compartment in habit formation, and provides a potential mechanism for how patches modify habitual behavior by exerting control over dopamine signaling.


2020 ◽  
Author(s):  
Fabien Naneix ◽  
Kate Z. Peters ◽  
Andrew M. J. Young ◽  
James E. McCutcheon

ABSTRACTDespite the essential role of protein intake for health and development, very little is known about the impact of protein restriction on neurobiological functions, especially at different stages of the lifespan. The dopamine system is a central actor in the integration of food-related processes and is influenced by physiological state and food-related signals. Moreover, it is highly sensitive to dietary effects during early life periods such as adolescence due to its late maturation. In the present study, we investigated the impact of protein restriction either during adolescence or adulthood on the function of the mesolimbic (nucleus accumbens) and nigrostriatal (dorsal striatum) dopamine pathways using fast-scan cyclic voltammetry in rat brain slices. In the nucleus accumbens, protein restriction in adults increased dopamine release in response to low and high frequency trains of stimulation (1-20 Hz). By contrast, protein restriction performed at adolescence decreased nucleus accumbens dopamine release. In the dorsal striatum, protein restriction has no impact on dopamine release when performed at adulthood but in adolescent rats we observed frequency-dependent increases in stimulated dopamine release. Taken together, our results highlight the sensitivity of the different dopamine pathways to the effect of protein restriction, as well as their vulnerability to deleterious diet effects at different life stages.


2021 ◽  
Author(s):  
Anna C Everett ◽  
Benjamin E. Graul ◽  
Daniel B. Watts ◽  
James Kayden Robinson ◽  
Rodrigo A. Espana ◽  
...  

Fast-scan cyclic voltammetry (FSCV) is an effective tool for measuring dopamine (DA) release and clearance throughout the brain, including the ventral and dorsal striatum. Striatal DA terminals are abundant with signals heavily regulated by release machinery and the dopamine transporter (DAT). Peak height is a common method for measuring release but can be affected by changes in clearance. The Michaelis-Menten model has been a standard in measuring DA clearance, but requires experimenter fitted modeling subject to experimenter bias. The current study presents the use of the first derivative (velocity) of evoked DA signals as an alternative approach for measuring dopamine release and clearance and can be used to distinguish the two measures. Maximal upwards velocity predicts reductions in DA peak height due to D2 and GABAB receptor stimulation and by alterations in calcium concentrations. The Michaelis-Menten maximal velocity (Vmax) measure, an approximation for DAT numbers, predicted maximal downward velocity in slices and in vivo. Dopamine peak height and upward velocity were similar between wildtype C57 (WT) and DAT knock out (DATKO) mice. In contrast, downward velocity was considerably reduced and exponential decay (tau) was increased in DATKO mice, supporting use of both measures for changes in DAT activity. In slices, the competitive DAT inhibitors cocaine, PTT and WF23 increased peak height and upward velocity differentially across increasing concentrations, with PTT and cocaine reducing these measures at high concentrations. Downward velocity and tau values decreased and increased respectively across concentrations, with greater potency and efficacy observed with WF23 and PTT. In vivo recordings demonstrated similar effects of WF23 and PTT on measures of release and clearance. Tau was a more sensitive measure at low concentrations, supporting its use as a surrogate for the Michaelis-Menten measure of apparent affinity (Km). Together, these results inform on the use of these measures for DA release and clearance.


2002 ◽  
Vol 87 (2) ◽  
pp. 1155-1158 ◽  
Author(s):  
Billy T. Chen ◽  
Marat V. Avshalumov ◽  
Margaret E. Rice

We showed previously that dopamine (DA) release in dorsal striatum is inhibited by endogenously generated hydrogen peroxide (H2O2). Here, we examined whether endogenous H2O2 can also modulate somatodendritic DA release in the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA), with companion measurements in DA terminal regions. Evoked DA release was monitored in brain slices using carbon-fiber microelectrodes with fast-scan cyclic voltammetry. Exogenous H2O2decreased DA release by 50–60% in SNc and VTA but only by 35% in nucleus accumbens. Whether endogenous H2O2 also modulated somatodendritic release was examined using the glutathione peroxidase inhibitor, mercaptosuccinate (MCS), which should increase stimulation-evoked H2O2levels. In the presence of MCS, DA release was suppressed by 30–40% in SNc as well as in dorsal striatum and nucleus accumbens. In striking contrast, DA release in the VTA was unaffected by MCS. These data are consistent with stronger H2O2 regulation or lower H2O2 generation in VTA than in the other regions. Importantly, oxidative stress has been linked causally to Parkinson's disease, in which DA cells in SNc degenerate, but VTA cells are spared. The present data suggest that differences in oxidant regulation or generation between SNc and VTA could contribute to this.


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