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Dopamine transients

Giuseppe Lanza, Cornelius G Bachmann, Imad Ghorayeb, Yuping Wang, Raffale Ferri, Walter Paulus
Neurophysiological techniques have been applied in restless legs syndrome (RLS) to obtain direct and indirect measures of central and peripheral nervous system excitability, as well as to probe different neurotransmission pathways. Data converge on the hypothesis that, from a pure electrophysiological perspective, RLS should be regarded as a complex sensorimotor disorder in which cortical, subcortical, spinal cord, and peripheral nerve generators are all involved in a network disorder, resulting in an enhanced excitability and/or decreased inhibition...
August 27, 2016: Sleep Medicine
Shuo Wang, Sujin Kim, Kelly P Cosgrove, Evan D Morris
The "linear parametric neurotransmitter PET" (lp-ntPET) model was introduced to capture the time course of transient endogenous neurotransmitter response to drug stimulus from dynamic PET data. We previously used this novel analysis tool to probe the short-lived dopamine (DA) response induced by cigarette smoking in the PET scanner. It allowed us to find a sex difference in the DA signature of cigarette smoking. To make best use of this tool to characterize neurotransmitter response to drug stimulus, the sensitivity of lp-ntPET to detect such responses must be maximized...
October 12, 2016: NeuroImage
Martin J Bobak, Matthew W Weber, Melissa A Doellman, Douglas R Schuweiler, Jeana M Athens, Steven A Juliano, Paul A Garris
Modafinil (MOD) exhibits therapeutic efficacy for treating sleep and psychiatric disorders, but its mechanism is incompletely understood. Compared to other psychostimulants inhibiting dopamine (DA) uptake, MOD weakly interacts with the dopamine transporter (DAT) and modestly elevates striatal dialysate DA, suggesting additional targets besides DAT. However, the ability of MOD to induce wakefulness is abolished with DAT knockout, conversely suggesting that DAT is necessary for MOD action. Another psychostimulant target, but one not established for MOD, is activation of phasic DA signaling...
October 12, 2016: Journal of Pharmacology and Experimental Therapeutics
A Acharjee, R Chaube, K P Joy
The commercial fish spawning inducer Ovaprim (OVP) containing a salmon gonadotropin-releasing hormone analogue and domperidone (a dopamine receptor-2 antagonist) has been widely used as an effective spawning inducer in artificial breeding of fishes. It induces a preovulatory LH surge resulting in final oocyte maturation (FOM) and ovulation through a mechanism involving a steroidogenic shift to secrete a maturation-inducing steroid (MIS). In the present study, a 0.5μL/g body weight dose of OVP each injected at 0h and 24h intraperitoneally into gravid female catfish, Heteropneustes fossilis resulted in periovulatory changes in gonadotropin (GtH) subunit gene expression and steroid hormone levels...
October 5, 2016: General and Comparative Endocrinology
Min Lin, Danielle Sambo, Habibeh Khoshbouei
: Methamphetamine (METH) is a substrate for the dopamine transporter that increases extracellular dopamine levels by competing with dopamine uptake and increasing reverse transport of dopamine via the transporter. METH has also been shown to alter the excitability of dopamine neurons. The mechanism of METH regulation of the intrinsic firing behaviors of dopamine neurons is less understood. Here we identified an unexpected and unique property of METH on the regulation of firing activity of mouse dopamine neurons...
October 5, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Neda Najafinobar, Lisa J Mellander, Michael E Kurczy, Johan Dunevall, Tina B Angerer, John S Fletcher, Ann-Sofie Cans
Neurons communicate via an essential process called exocytosis. Cholesterol, an abundant lipid in both secretory vesicles and cell plasma membrane can affect this process. In this study, amperometric recordings of vesicular dopamine release from two different artificial cell models created from a giant unilamellar liposome and a bleb cell plasma membrane, show that with higher membrane cholesterol the kinetics for vesicular release are decelerated in a concentration dependent manner. This reduction in exocytotic speed was consistent for two observed modes of exocytosis, full and partial release...
2016: Scientific Reports
Giovanni Hernandez, Marie-Pierre Cossette, Peter Shizgal, Pierre-Paul Rompré
Glutamate stimulates ventral midbrain (VM) N-Methyl-D-Aspartate receptors (NMDAR) to initiate dopamine (DA) burst firing activity, a mode of discharge associated with enhanced DA release and reward. Blockade of VM NMDAR, however, enhances brain stimulation reward (BSR), the results can be explained by a reduction in the inhibitory drive on DA neurons that is also under the control of glutamate. In this study, we used fast-scan cyclic voltammetry (FSCV) in anesthetized animals to determine whether this enhancement is associated with a change in phasic DA release in the nucleus accumbens...
2016: Frontiers in Behavioral Neuroscience
Alina Tabor, Siegfried Weisenburger, Ashutosh Banerjee, Nirupam Purkayastha, Jonas M Kaindl, Harald Hübner, Luxi Wei, Teja W Grömer, Johannes Kornhuber, Nuska Tschammer, Nigel J M Birdsall, Gregory I Mashanov, Vahid Sandoghdar, Peter Gmeiner
G protein-coupled receptors (GPCRs), including dopamine receptors, represent a group of important pharmacological targets. An increased formation of dopamine receptor D2 homodimers has been suggested to be associated with the pathophysiology of schizophrenia. Selective labeling and ligand-induced modulation of dimerization may therefore allow the investigation of the pathophysiological role of these dimers. Using TIRF microscopy at the single molecule level, transient formation of homodimers of dopamine receptors in the membrane of stably transfected CHO cells has been observed...
2016: Scientific Reports
Pierre Sokoloff, Bernard Le Foll
This review updates the existing knowledge suggesting a role for the D3 receptor in schizophrenia and drug addiction. The D3 receptor is expressed in brain regions controlling reward, emotions, and motivation. Antipsychotics bind in vitro to the D3 receptor with similar affinity as to the D2 receptor, and occupancy of D3 receptors in vivo by these compounds given acutely at clinical dosage have been demonstrated in Positron Emission Tomography (PET) studies. The D3 receptor modulates glutamatergic pathways from the prefrontal cortex to subcortical areas, either directly by interacting with N-methyl-D-aspartate (NMDA) receptors in the nucleus accumbens, or indirectly by controlling dopamine release from ventral tegmental area neurons...
September 7, 2016: European Journal of Neuroscience
Kristen A Schmidt, Brian A Palmer, Mark A Frye
BACKGROUND: This case chronicles the unique presentation of psychotic mixed mania in a female 5 months after parturition and 1 week following breastfeeding discontinuation, highlighting a rarely recognized mania risk factor that is temporally delayed from parturition: breastfeeding discontinuation. CASE PRESENTATION: A 25-year-old G1P1 female with a past psychiatric history of a depressive episode in adolescence presented to the Emergency Department with her 5-month-old daughter, fiancée, and family 1 week after breastfeeding cessation...
December 2016: International Journal of Bipolar Disorders
Anu G Nair, Upinder S Bhalla, Jeanette Hellgren Kotaleski
In reward learning, the integration of NMDA-dependent calcium and dopamine by striatal projection neurons leads to potentiation of corticostriatal synapses through CaMKII/PP1 signaling. In order to elicit the CaMKII/PP1-dependent response, the calcium and dopamine inputs should arrive in temporal proximity and must follow a specific (dopamine after calcium) order. However, little is known about the cellular mechanism which enforces these temporal constraints on the signal integration. In this computational study, we propose that these temporal requirements emerge as a result of the coordinated signaling via two striatal phosphoproteins, DARPP-32 and ARPP-21...
September 2016: PLoS Computational Biology
Louis J De Felice
Serotonin transporters (SERTs) are largely recognized for one aspect of their function-to transport serotonin back into the presynaptic terminal after its release. Another aspect of their function, however, may be to generate currents large enough to have physiological consequences. The standard model for electrogenic transport is the alternating access model, in which serotonin is transported with a fixed ratio of co-transported ions resulting in net charge per cycle. The alternating access model, however, cannot account for all the observed currents through SERT or other monoamine transporters...
2016: F1000Research
Mark P V Begieneman, Ellis N Ter Horst, Liza Rijvers, Elisa Meinster, Rene Leen, Jeanette Pankras, Jan Fritz, Bela Kubat, René J P Musters, Andre van Kuilenberg, Jan Stap, Hans W M Niessen, Paul A J Krijnen
AIMS: Excess catecholamine levels are suggested to be cardiotoxic and to underlie stress-induced heart failure. The cardiotoxic effects of noradrenaline and adrenaline are well recognized. However, although cardiac and circulating dopamine levels are also increased in stress-cardiomyopathy patients, knowledge regarding putative toxic effects of excess dopamine levels on cardiomyocytes is scarce. We now studied the effects of elevated dopamine levels in H9C2 cardiomyoblasts. METHODS AND RESULTS: H9C2 cells were cultured and treated with dopamine (200 μM) for 6, 24 and 48 hours...
August 12, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Maximiliano Rapanelli, Luciana R Frick, Kyla D Horn, Rivka C Schwarcz, Vladimir Pogorelov, Angus C Nairn, Christopher Pittenger
The basal ganglia have a central role in motor patterning, habits, motivated behaviors, and cognition as well as in numerous neuropsychiatric disorders. Receptors for histamine, especially the H3 receptor (H3R), are highly expressed in the striatum, the primary input nucleus of the basal ganglia, but their effects on this circuitry have been little explored. H3R interacts with dopamine (DA) receptors ex vivo; the nature and functional importance of these interactions in vivo remain obscure. We found H3R activation with the agonist R-(-)-α-methylhistamine to produce a unique time- and cell type-dependent profile of molecular signaling events in the striatum...
September 30, 2016: Journal of Biological Chemistry
Pierre Berthet, Mikael Lindahl, Philip J Tully, Jeanette Hellgren-Kotaleski, Anders Lansner
The brain enables animals to behaviorally adapt in order to survive in a complex and dynamic environment, but how reward-oriented behaviors are achieved and computed by its underlying neural circuitry is an open question. To address this concern, we have developed a spiking model of the basal ganglia (BG) that learns to dis-inhibit the action leading to a reward despite ongoing changes in the reward schedule. The architecture of the network features the two pathways commonly described in BG, the direct (denoted D1) and the indirect (denoted D2) pathway, as well as a loop involving striatum and the dopaminergic system...
2016: Frontiers in Neural Circuits
J Thomsen, N Himmerkus, N Holland, F J Sartoris, M Bleich, M Tresguerres
The excretion of nitrogenous waste products in the form of ammonia (NH3) and ammonium (NH4 (+)) is a fundamental process in aquatic organisms. For mytilid bivalves, little is known about the mechanisms and sites of excretion. This study investigated the localization and the mechanisms of ammonia excretion in mytilid mussels. An Rh protein was found to be abundantly expressed in the apical cell membrane of the plicate organ, which was previously described as a solely respiratory organ. The Rh protein was also expressed in the gill, although at significantly lower concentrations, but was not detectable in mussel kidney...
August 1, 2016: Journal of Experimental Biology
Diogo Pimentel, Jeffrey M Donlea, Clifford B Talbot, Seoho M Song, Alexander J F Thurston, Gero Miesenböck
Sleep disconnects animals from the external world, at considerable risks and costs that must be offset by a vital benefit. Insight into this mysterious benefit will come from understanding sleep homeostasis: to monitor sleep need, an internal bookkeeper must track physiological changes that are linked to the core function of sleep. In Drosophila, a crucial component of the machinery for sleep homeostasis is a cluster of neurons innervating the dorsal fan-shaped body (dFB) of the central complex. Artificial activation of these cells induces sleep, whereas reductions in excitability cause insomnia...
August 18, 2016: Nature
Brandi N Bowman, James J Nawarskas, Joe R Anderson
Loop diuretics are central to the management of fluid overload in acute decompensated heart failure. However, a variance in the response to loop diuretics can alter a patient's clinical course and has an adverse effect on clinical outcomes. Thus, a diminished response to loop diuretics is an important clinical issue. Factors thought to contribute to diuretic resistance include erratic oral absorption in congested states and postdiuretic sodium retention. Further contributing to diuretic resistance in patients with advanced heart failure are decreases in renal perfusion and alterations in sodium handling that occur in an attempt to maintain circulatory homeostasis...
September 2016: Cardiology in Review
Megan E Fox, Nathan T Rodeberg, R Mark Wightman
Dysregulated catecholamine signaling has long been implicated in drug abuse. Although much is known about adaptations following chronic drug administration, little work has investigated how a single drug exposure paired with withdrawal influences catecholamine signaling in vivo. We used fast-scan cyclic voltammetry in freely moving rats to measure real-time catecholamine overflow during acute morphine exposure and naloxone-precipitated withdrawal in two regions associated with the addiction cycle: the dopamine-dense nucleus accumbens (NAc) and norepinephrine-rich ventral bed nucleus of the stria terminalis (vBNST)...
August 17, 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Cici Chenliu, Xiaoye Sheng, Pauline Dan, Yang Qu, Victoria Claydon, Eric Lin, Leif Hove-Madsen, Shubhayan Sanatani, Glen F Tibbits
BACKGROUND: Post-operative arrhythmias such as Junctional Ectopic Tachycardia (JET) and atrioventricular block (AVB) are serious post-operative complications for children with congenital heart disease. We hypothesize that ischemia reperfusion (I/R) related changes exacerbate these post-operative arrhythmias in the neonate heart and the administration of post-operative inotropes is contributory. OBJECTIVE: To study the effects of I/R and post-ischemic dopamine (DA) application on the automaticity and rhythmicity in immature and mature pacemaker cells and whole heart preparations...
July 20, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
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