Search results for "Neurotransmitter"

Efficiency of antidepressant drugs as monoamine reuptake inhibitors: analysis of the hydrophobicity influence using biopartitioning micellar chromato…

2004

The reuptake blockade of biogenic amines by antidepressants is related not only to their therapeutics effects, but also to their side effects and potential drug-drug interactions. As an alternative to classical quantitative structure-activity relationships studies, in this work we propose different quantitative retention-activity relationships (QRAR) models that are able to describe the monoamine reuptake inhibition by antidepressants. The retention of compounds is measured using a biopartitioning micellar chromatography (BMC) system that can simulate the same hydrophobic, electronic and steric molecular interactions as those that condition drug activity. Since all the compounds considered …

Coincident glutamatergic depolarizations enhance GABAA receptor-dependent Cl- influx in mature and suppress Cl- efflux in immature neurons.

2021

The impact of GABAergic transmission on neuronal excitability depends on the Cl--gradient across membranes. However, the Cl--fluxes through GABAA receptors alter the intracellular Cl- concentration ([Cl-]i) and in turn attenuate GABAergic responses, a process termed ionic plasticity. Recently it has been shown that coincident glutamatergic inputs significantly affect ionic plasticity. Yet how the [Cl-]i changes depend on the properties of glutamatergic inputs and their spatiotemporal relation to GABAergic stimuli is unknown. To investigate this issue, we used compartmental biophysical models of Cl- dynamics simulating either a simple ball-and-stick topology or a reconstructed CA3 neuron. Th…

From the Golgi-Cajal mapping to the transmitter-based characterization of the neuronal networks leading to two modes of brain communication: Wiring a…

2007

After Golgi-Cajal mapped neural circuits, the discovery and mapping of the central monoamine neurons opened up for a new understanding of interneuronal communication by indicating that another form of communication exists. For instance, it was found that dopamine may be released as a prolactin inhibitory factor from the median eminence, indicating an alternative mode of dopamine communication in the brain. Subsequently, the analysis of the locus coeruleus noradrenaline neurons demonstrated a novel type of lower brainstem neuron that monosynaptically and globally innervated the entire CNS. Furthermore, the ascending raphe serotonin neuron systems were found to globally innervate the forebrai…

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…

Separation of presynaptic Cav2 and Cav1 channel function in synaptic vesicle exo- and endocytosis by the membrane anchored Ca2+ pump PMCA

2021

Significance Synaptic vesicle (SV) release from presynaptic terminals requires nanometer precise control of action potential (AP)–triggered calcium influx through voltage-gated calcium channels (VGCCs). SV recycling also depends on calcium signals, though in different spatiotemporal domains. Mechanisms for separate control of SV release and recycling by AP-triggered calcium influx remain elusive. Here, we demonstrate largely independent regulation of release and recycling by two different populations of VGCCs (Cav2, Cav1), identify Cav1 as one of potentially multiple calcium entry routes for endocytosis regulation, and show functional separation of simultaneous calcium signals in the nanome…

Retraction notice to “Relationship between dopamine D2 receptor occupancy, clinical response, and drug and monoamine metabolites levels in plasma and…

2012

Plasticity of mouse enteric synapses mediated through endocannabinoid and purinergic signaling

2012

The myenteric and submucosal plexuses of the enteric nervous system (ENS) exist as interconnected integrative nerve networks within the wall of the gastrointestinal (GI) tract. Activity of the ENS is responsible for the control of the digestive and protective functions of the gut.1 Synaptic transmission between enteric neurons propagates information from intrinsic afferent neurons to interneurons, and then from interneurons to motor neurons that control final effectors such as smooth muscle and the secretory epithelium. Acetylcholine (ACh) is the major excitatory neurotransmitter in the myenteric plexus, acting on nicotinic receptors at synapses between neurons and on muscarinic receptors a…

Drug interactions at GABA(A) receptors.

2002

Neurotransmitter receptor systems have been the focus of intensive pharmacological research for more than 20 years for basic and applied scientific reasons, but only recently has there been a better understanding of their key features. One of these systems includes the type A receptor for the gamma-aminobutyric acid (GABA), which forms an integral anion channel from a pentameric subunit assembly and mediates most of the fast inhibitory neurotransmission in the adult vertebrate central nervous system. Up to now, depending on the definition, 16-19 mammalian subunits have been cloned and localized on different genes. Their assembly into proteins in a poorly defined stoichiometry forms the basi…

Expression of synapsin I gene in primary cultures of differentiating rat cortical neurons

1995

Synapsin I is a neuron-specific protein which is present in two isoforms, Ia and Ib. In the last few years this protein has been demonstrated to play a central role in the regulation of neurotransmitter release and synaptic plasticity. In this paper the developmental expression of this protein has been investigated in primary neuronal cultures from fetal rat brain cortices. The presence of thyroid hormone in the culture medium stimulates an early expression of the protein without exerting any effect at the level of mRNA transcription and accumulation. These observations implicate a T3-dependent regulation of this neuron-specific gene at the level of mRNA translation. © 1995 Plenum Publishin…

Identification of the cannabinoid receptor type 1 in serotonergic cells of raphe nuclei in mice.

2007

The endocannabinoid system (ECS) possesses neuromodulatory functions by influencing the release of various neurotransmitters, including GABA, noradrenaline, dopamine, glutamate and acetylcholine. Even though there are studies indicating similar interactions between the ECS and the serotonergic system, there are no results showing clear evidence for type 1 cannabinoid receptor (CB1) location on serotonergic neurons. In this study, we show by in situ hybridization that a low but significant fraction of serotonergic neurons in the raphe nuclei of mice contains CB1 mRNA as illustrated by the coexpression with the serotonergic marker gene tryptophane hydroxylase 2, the rate limiting enzyme for t…