Search results for "dopaminergic"

Cannabis and the Mesolimbic System

2016

Abstract Cannabis sativa (hemp) is a flowering annual plant whose phytochemical by-products, hashish and marihuana, are the most widely produced and most frequently used illicit drugs in Europe. Δ 9 -Tetrahydrocannabinol is the primary psychoactive constituent, responsible, in a dose-related manner, for euphoria, cognitive effects, and psychotic symptoms, as well as the addictive potential of smoked cannabis due to its interference with the mesolimbic dopaminergic system. Cannabis as well as endocannabinoids acts mainly at the presynaptic levels in several brain regions, including the nucleus accumbens and ventral tegmental area, where it modulates synaptic activity. Through the modulation …

Acetaldehyde as a drug of abuse: insight into AM281 administration on operant-conflict paradigm in rats

2013

Increasing evidence focuses on acetaldehyde (ACD) as the mediator of the rewarding and motivational properties of ethanol. Indeed, ACD stimulates dopamine release in the nucleus accumbens and it is self-administered under different conditions. Besides the dopaminergic transmission, the endocannabinoid system has been reported to play an important role in ethanol central effects, modulating primary alcohol rewarding effect, drug-seeking and relapse behaviour. Drug motivational properties are highlighted in operant paradigms which include response-contingent punishment, a behavioural equivalent of compulsive drug use despite adverse consequences. The aim of this study was thus to characterize…

ChemInform Abstract: Enantioselective Syntheses of Dopaminergic (R)- and (S)-Benzyltetrahydroisoquinolines.

2010

Optically pure (1S,R)- and (1R,S)-benzyltetrahydroisoquinolines (BTHIQs), 12a,b as the major diastereomers, were prepared by stereoselective reduction of the isoquinolinium salt possessing (R)- and (S)-phenylglycinol as the chiral auxiliary, respectively. The absolute configurations of (1S,R)-13a hydrochloride (O-debenzoylated derivative from 12a) and (1R,S)-12b diastereomers were unambiguously determined by single-crystal X-ray analysis. Reductive removal of the chiral auxiliary group, subsequent N-propylation, and cleavage of the methylenedioxy group furnished the optically active catecholamines (1S)-16a and (1R)-16b in good overall yield. We have separately prepared for the first time pa…

Dopamine Autoreceptor Agonists in the Treatment of Schizophrenia and Major Depression*

1992

Dopamine autoreceptor agonists reduce the firing rate, synthesis, and release of dopamine in dopaminergic neurons by means of a negative feedback mechanism via stimulation of autoreceptors. Moreover, dopamine autoreceptor agonists are able to stimulate supersensitive but not normosensitive postsynaptic receptors. For dopamine autoreceptor agonists, therapeutic effects by readjustment of excessive or deficient dopaminergic function have been postulated for positive and negative schizophrenic symptomatology as well as for subtypes of depressive disorders. Investigations on the therapeutic effects of autoreceptor-nonselective dopamine agonists in schizophrenia or depression have yielded incons…

A Diet for Dopaminergic Neurons?

2009

Parkinson's disease (PD) is the second most common neurodegenerative disease, which unfortunately is still fatal. Since the discovery of dopamine (DA) neuronal cell loss within the substantia nigra in PD, the past decades have seen the understanding of the pathophysiological mechanisms underlying the degenerative process advance at a very impressive rate. Nevertheless, there is at present no cure for PD. Although there are no proven therapies for prevention, a large body of evidence from animal studies has highlighted the paramount role of dietary factors in counteracting DA degeneration. Consistently, associations between the risk of developing PD and the intake of nutrients, individual fo…

Nuovi derivati della Dopamina nell’Addiction da sostanze d’abuso: studi preclinici su modelli sperimentali murini

Studies on a new potential dopaminergic agent: in vitro BBB permeability, in vivo behavioural effects and molecular docking evaluation.

2015

2-Amino-N-[2-(3,4-dihydroxy-phenyl)-ethyl]-3-phenyl-propionamide (DA-PHEN) has been previously synthesized to obtain a potential prodrug capable of release dopamine (DA) into CNS. However, DA-PHEN could act per se as a dopaminergic drug. In this study, the permeability transport (Pe), obtained by parallel artificial permeability assay (PAMPA), indicated a low passive transcellular transport (Pe = 0.32 ± 0.01 × 10(-6 )cm/s). Using the Caco-2 cell system, the Papp AP-BL in absorptive direction (3.36 ± 0.02 × 10(-5 )cm/s) was significantly higher than the Papp BL-AP in secretive direction (1.75 ± 0.07 × 10(-5 )cm/s), suggesting a polarized transport. The efflux ratio (Papp AP-BL/Papp BL-AP = 0…

Reduction of red-green discrimination by dopamine D1 receptor antagonists and retinal dopamine depletion

1996

AbstractReduction of wavelength discrimination ability in the 560–640 nm range, but not in the 404–540 nm range, has been demonstrated in goldfish after intravitreal injection of D1-dopamine receptor antagonists. Intravitreal injection of the dopaminergic neurotoxin 6-OH-dopamine severely reduced wavelength discrimination ability in the 540–661 nm range within 3 days. Discrimination ability could be reconstituted by the Dl-agonist SKF 38393. Animals recovered from injection of 6-OH-dopamine within 14–16 days. No change of wavelength discrimination was induced by 6-OH-dopamine in the 461–540 nm range. We conclude that under photopic conditions dopamine modulates retinal mechanisms involved i…

Impact of adolescent methamphetamine use on social cognition: A human-mice reverse translation study.

2021

Background: Methamphetamine dependence is associated with social cognition deficits that may underpin negative social outcomes. However, there are considerable inter-individual differences in social cognition within people with methamphetamine dependence, with age of onset of methamphetamine use being a potential contributing factor. Materials and methods: We conducted two sequential studies examining the link between age of onset of methamphetamine use (adolescence versus young adulthood) and performance in social cognition tests: (1) a human cross-sectional study in 95 participants with methamphetamine dependence varying in age of onset (38 with adolescent onset and 57 with adult onset) a…

Dopaminergic control of feline hippocampal epilepsy: A nigrophippocampal pathway

1991

Abstract Substantia nigra is a mesencephalic structure inserted along several circuits which appear to play a key role in epilepsy. In previous researches we postulated that substantia nigra pars compacta (SNpc) may be the site of a precise control of hippocampal epilepsy while substantia nigra pars reticulata (SNpr) may exert a modulation of both neocortical epilepsy and spreading of hyperactivity toward a motor target. In order to better understand mechanisms subserving nigral action in feline hippocampal epilepsy we electrically stimulated SNpc (dopaminergic), before and after sulpiride (dopamine receptor-antagonist) intravenous injection. Furthermore we compared hippocampal epileptiform…