Dopamine receptors, which belong to the family of G protein-coupled receptors, are very substantial regulators in the brain and therefore important targets in drug discovery. Radioligand binding assay has been the method of choice for screening novel dopaminergic drugs for decades. We demonstrate that fluorescent ligand BodipyFL-SKF83566 binding to dopamine D receptors expressed in budded baculovirus particles can be characterized with fluorescent anisotropy (FA) based assay and that this is a valuable alternative to the radioligand binding assay. High binding affinity (K = 5.2 nM) and fast association and dissociation kinetics (half-lives 40 s and 70 s, respectively) make BodipyFL-SKF83566 a suitable fluorescent ligand for this type of experiments. Good correlation between pK values of 11 different dopaminergic ligands determined in competition binding experiments with radioligand [H]SCH23390 or BodipyFL-SKF83566 (R = 0.96, slope not significantly different from unity) further validates the FA assay. In addition to competitor's affinity, the method also enables to quantify the apparent pIC values in time and hence kinetic properties of an unlabeled ligand can be estimated from the same competition binding experiment. Due to the homogenous nature of the FA assay reactions can be monitored in real time without any risk of precipitation of receptors in budded baculovirus particles. Despite the lack of coupled G proteins, the proposed novel assay system allows on-line monitoring of ligand binding to dopamine D receptors that could be easily applicable in early drug screening.
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http://dx.doi.org/10.1016/j.ejphar.2018.09.008 | DOI Listing |
Neurobiol Dis
December 2024
Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada. Electronic address:
Background: Altered balance between striatal direct and indirect pathways contributes to early motor, cognitive and psychiatric symptoms in Huntington disease (HD). While degeneration of striatal D2-type dopamine receptor (D2)-expressing indirect pathway medium spiny neurons (iMSNs) occurs prior to that of D1-type dopamine receptor (D1)-expressing direct pathway neurons, altered corticostriatal synaptic function precedes degeneration. D2-mediated signaling on iMSNs reduces their excitability and promotes endocannabinoid (eCB) synthesis, suppressing glutamate release from cortical afferents.
View Article and Find Full Text PDFJ Org Chem
December 2024
Ecole polytechnique de Bruxelles, Engineering of Molecular NanoSystems, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP165/64, B-1050 Brussels, Belgium.
Many bioactive molecules contain primary ammonium groups, generating significant interest in developing selective receptors for ammonium ions. A promising strategy involves the use of polyaromatic cavitands to achieve size and shape selectivity through their cavity. However, designing effective receptors for ammonium ions in aqueous media is challenging due to the competitive nature of water.
View Article and Find Full Text PDFNeuropharmacology
December 2024
- Department of Psychopharmacology, Valdman Institute of Pharmacology, Pavlov First Saint Petersburg State Medical University, Saint Petersburg, Russia.
Background: Apathy is a syndrome of decreased goal-directed activity, one of the main features of different brain disorders. Despite its high prevalence and life-threatening potential, there are currently very few options for its pharmacological treatment, which may be related to the lack of valid animal models.
Aims: The vesicular monoamine transporter 2 inhibitor tetrabenazine (TBZ) was used in this study to model apathy-related behavior in pathologies linked to a depletion of dopamine.
Life Sci
December 2024
Pharmacology and Toxicology Laboratory, Dietetics and Nutrition Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, Himachal Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India. Electronic address:
Aims: Hyperammonaemia (HA) is a metabolic disorder characterized by increased ammonia levels in the blood and is associated with severe neurological impairments. Some previous findings have shown the involvement of the nitric oxide pathway in HA-induced neurological impairments. The current study explored the impact of tadalafil on neurological impairments induced by HA in a zebrafish larval model due to its reported indirect interactions with the nitric oxide pathway.
View Article and Find Full Text PDFNeurobiol Learn Mem
December 2024
Department of Psychology, The University of Texas at Austin, Austin TX 78712, United States; Department of Neurology, The University of Texas at Austin, Austin TX 78712, United States; Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin TX 78712, United States. Electronic address:
The ability to choose between options that differ in their risks and rewards depends on brain regions within the mesocorticolimbic circuit and regulation of their activity by neurotransmitter systems. Dopamine neurotransmission in particular plays a critical role in modulating such risk-taking behavior; however, the contribution of other major modulatory neurotransmitters, such as acetylcholine, is not as well-defined, especially for decision making in which the risk associated with more rewarding outcomes involves adverse consequences. Consequently, the goal of the current experiments was to examine how cholinergic signaling influences decision making involving risk of explicit punishment.
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