Search results for "Dopamine receptor"

3-Chlorotyramine Acting as Ligand of the D2 Dopamine Receptor. Molecular Modeling, Synthesis and D2 Receptor Affinity.

2014

We synthesized and tested 3-chlorotyramine as a ligand of the D2 dopamine receptor. This compound displayed a similar affinity by this receptor to that previously reported for dopamine. In order to understand further the experimental results we performed a molecular modeling study of 3-chlorotyramine and structurally related compounds. By combining molecular dynamics simulations with semiempirical (PM6), ab initio and density functional theory calculations, a simple and generally applicable procedure to evaluate the binding energies of these ligands interacting with the D2 dopamine receptors is reported here. These results provided a clear picture of the binding interactions of these compou…

A subset of ventral tegmental area dopamine neurons responds to acute ethanol

2015

The mechanisms by which alcohol drinking promotes addiction in humans and self-administration in rodents remain obscure, but it is well known that alcohol can enhance dopamine (DA) neurotransmission from neurons of the ventral tegmental area (VTA) and increase DA levels within the nucleus accumbens and prefrontal cortex. We recorded from identified DA neuronal cell bodies within ventral midbrain slices prepared from a transgenic mouse line (TH-GFP) using long-term stable extracellular recordings in a variety of locations and carefully mapped the responses to applied ethanol (EtOH). We identified a subset of DA neurons in the medial VTA located within the rostral linear and interfascicular n…

1-(2′-Bromobenzyl)-6,7-dihydroxy-N-methyl-tetrahydroisoquinoline and 1,2-Demethyl-nuciferine as Agonists in Human D2 Dopamine Receptors

2020

Certain D2-like dopamine receptor (DR) agonists are useful therapeutically as antiparkinsonian drugs, whereas D2-like DR antagonists or partial agonists are proven effective as antipsychotics. Two ...

The dopamine D3 antagonist U-99194A maleate increases social behaviors of isolation-induced aggressive male mice.

1999

Rationale: Blockade of D1/D2 dopamine receptors produce an antiaggressive action commonly associated with an impairment of other motor behaviors. The D3 receptor seems to present opposite actions to the D1 and D2, since the blockade of this receptor produces stimulation of motor activity which has been associated with an increase in dopamine neurotransmission. Objective: In this work, the action of the dopamine D3 antagonist U-99194a maleate on locomotor activity and in a social interaction test in male mice was evaluated. Methods: Animals isolated during 30 days were treated with U-99194a maleate (20–40 mg/kg) or saline and locomotor activity was measured 20 min after drug administration. …

Dopamine D2 receptors mediate the increase in reinstatement of the conditioned rewarding effects of cocaine induced by acute social defeat

2017

Social stress modifies the activity of brain areas involved in the rewarding effects of psychostimulants, inducing neuroadaptations in the dopaminergic mesolimbic system and modifying the sensitivity of dopamine receptors. In the present study we evaluated the effect of the dopamine D1- and D2-like receptor antagonists (SCH23390 and raclopride, respectively) on the short-time effects of acute social defeat (ASD). Male OF1 mice were socially defeated before each conditioning session of the conditioned place preference (CPP) induced by 1mg/kg or 25mg/kg of cocaine plus the corresponding dopamine antagonist. A final experiment was designed to evaluate the effect of the dopamine antagonists on …

Synthesis of hexahydrocyclopenta[ij]isoquinolines as a new class of dopaminergic agents.

2014

In this study, we have described the synthesis of the tricyclic 1,2,3,7,8,8a-hexahydrocyclopenta [ij]isoquinoline (HCPIQ). Herein, six differently substituted 5,6-dioxygenated-7-phenyl-HCPIQs have been synthesized using a new methodology via (E)-1-styryl-THIQ by Friedel-Crafts cyclization with Eaton's reagent. Results showed that HCPIQs (3, 3a-e) displayed a moderate affinity for D1 dopamine receptors (DR) in the micromolar range, furthermore the catecholic HCPIQs 3a (NH), 3c (NCH3) and 3e (NCH2CHCH2) exhibited outstanding affinity and high selectivity towards D2 DR. Indeed, 3a, 3c and 3e showed Ki values of 29 nM, 13 nM and 18 nM, respectively, and HCPIQs 3a (NH) and 3c (NCH3) displayed a …

Dopamine autoreceptor agonists in the treatment of schizophrenic disorders

1993

Abstract 1. Synthesis and release of dopamine as well as firing rates of dopaminergic neurons are controlled by stimulation of autoreceptors via a negative feedback regulation, investigations on therapeutic effects of autoreceptor-nonselective dopamine agonists in schizophrenia have yielded inconsistent results. 2. With respect to the dopamine hypothesis of schizophrenia, dopamine autoreceptor agonists have been tested in positive schizophrenic symptomatology in order to reduce the postulated excess of central dopaminergic activity. However, administration of selective dopamine autoreceptor agonists like talipexole or roxindole did not result in a significant improvement of psychopathologic…

Presynaptic regulation of the electrically evoked release of endogenous dopamine from the isolated neurointermediate lobe or isolated neural lobe of …

1988

Isolated neurointermediate lobes (NILs) or isolated neural lobes (NLs) of the rat pituitary gland were incubated in Krebs-HEPES solution which contained pargyline and the dopamine uptake inhibitor GBR 12921. The release of endogenous dopamine was determined by HPLC with electrochemical detection. Electrical stimulation of the pituitary stalk induced a frequency-dependent release of dopamine. The release of dopamine from the combined NIL evoked by stimulation at 15 Hz was increased by 130% in the presence of the dopamine D2 receptor antagonist, (-)-sulpiride; the (+)-enantiomer of sulpiride had virtually no effect. When the stimulation frequency was 3 Hz (-)-sulpiride caused an increase in d…

Genetic polymorphisms of the dopamine D2 and D3 receptor and neuroleptic drug effects in schizophrenic patients

2001

Opioid Inhibition of Oxytocin Release, but not Autoinhibition of Dopamine Release May Involve Activation of Potassium (K+) Channels

1991

ABSTRACT Release of oxytocin (Ox) or dopamine (DA) from the isolated neural lobes or neurointermediate lobes, respectively, was evoked by high K + (30 or 45 mM). Naloxone (1-10 μmol/l) which largely enhances the impulse-induced release of Ox had no effect on Ox release evoked by 30 or 45 mM K + . In the presence of 10 mM tetraethylammonium (TEA), Ox release evoked by 30 or 45 mM K + was increased 2-3fold; nevertheless, naloxone caused a further 2-3fold increase. Barium (500 μM) and quinidine (300 μM) antagonized the effect of naloxone observed in the presence of TEA. (-)-Sulpiride (10 μM) enhanced the release of DA evoked by 30 and 45 mM K + by 94 % and 19 %, respectively. TEA enhanced the …