Page last updated: 2024-10-24

response to dopamine

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a dopamine stimulus. [GO_REF:0000071, GOC:mr, GOC:TermGenie, PMID:11118945]

Dopamine, a neurotransmitter synthesized from the amino acid tyrosine, plays a critical role in a wide range of physiological processes, including reward, motivation, learning, movement, and attention. Its signaling pathway is initiated when dopamine molecules bind to specific dopamine receptors, which are G protein-coupled receptors (GPCRs) located on the surface of neurons. There are five main types of dopamine receptors: D1, D2, D3, D4, and D5.

Upon dopamine binding, the activated receptor triggers a cascade of intracellular events that ultimately lead to changes in neuronal activity. The specific cellular response depends on the type of dopamine receptor involved. For example, D1-like receptors (D1 and D5) activate the G protein Gs, which stimulates the production of cyclic adenosine monophosphate (cAMP), a second messenger molecule. cAMP, in turn, activates protein kinase A (PKA), a key enzyme that phosphorylates and regulates the activity of various proteins, leading to changes in gene expression, neuronal excitability, and synaptic plasticity.

In contrast, D2-like receptors (D2, D3, and D4) activate the G protein Gi, which inhibits the production of cAMP and can also activate other signaling pathways, including the MAP kinase pathway. The activation of these signaling pathways results in different cellular responses, such as inhibition of neuronal activity, modulation of neurotransmitter release, and regulation of gene expression.

Dopamine signaling is intricately regulated by various mechanisms, including reuptake, metabolism, and receptor desensitization. Once dopamine has been released into the synapse, it is rapidly removed from the synaptic cleft by a specific transporter protein called dopamine transporter (DAT). Dopamine is then metabolized by enzymes such as monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). These enzymes break down dopamine into inactive metabolites, preventing prolonged signaling. Furthermore, dopamine receptors are subject to desensitization, a process that reduces their responsiveness to dopamine over time. This mechanism prevents excessive signaling and ensures proper regulation of dopamine-mediated responses.

Disruptions in dopamine signaling have been implicated in various neurological and psychiatric disorders, including Parkinson's disease, schizophrenia, and addiction. For instance, Parkinson's disease is characterized by a loss of dopamine-producing neurons in the substantia nigra, a brain region involved in motor control. This loss of dopamine leads to motor impairments such as tremors, rigidity, and slow movements. Conversely, excessive dopamine signaling in certain brain regions is thought to contribute to the development of schizophrenia, a disorder characterized by hallucinations, delusions, and cognitive deficits. Similarly, addiction is often associated with alterations in dopamine signaling pathways in reward circuits of the brain, leading to cravings, dependence, and compulsive drug-seeking behavior.

The complex and multifaceted nature of dopamine signaling highlights its crucial role in regulating a wide range of brain functions. Understanding the intricacies of this system is essential for developing effective treatments for various neurological and psychiatric disorders.
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Proteins (1)

ProteinDefinitionTaxonomy
Catechol O-methyltransferaseA catechol O-methyltransferase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P21964]Homo sapiens (human)

Compounds (8)

CompoundDefinitionClassesRoles
oxyquinolineOxyquinoline: An antiseptic with mild fungistatic, bacteriostatic, anthelmintic, and amebicidal action. It is also used as a reagent and metal chelator, as a carrier for radio-indium for diagnostic purposes, and its halogenated derivatives are used in addition as topical anti-infective agents and oral antiamebics.

quinolin-8-ol : A monohydroxyquinoline that is quinoline substituted by a hydroxy group at position 8. Its fungicidal properties are used for the control of grey mould on vines and tomatoes.
monohydroxyquinolineantibacterial agent;
antifungal agrochemical;
antiseptic drug;
iron chelator
verapamil2-(3,4-dimethoxyphenyl)-5-{[2-(3,4-dimethoxyphenyl)ethyl](methyl)amino}-2-(propan-2-yl)pentanenitrile : A tertiary amino compound that is 3,4-dimethoxyphenylethylamine in which the hydrogens attached to the nitrogen are replaced by a methyl group and a 4-cyano-4-(3,4-dimethoxyphenyl)-5-methylhexyl group.

verapamil : A racemate comprising equimolar amounts of dexverapamil and (S)-verapamil. An L-type calcium channel blocker of the phenylalkylamine class, it is used (particularly as the hydrochloride salt) in the treatment of hypertension, angina pectoris and cardiac arrhythmia, and as a preventive medication for migraine.

Verapamil: A calcium channel blocker that is a class IV anti-arrhythmia agent.
aromatic ether;
nitrile;
polyether;
tertiary amino compound
8-hydroxyquinoline-5-sulfonic acid8-hydroxyquinoline-5-sulfonic acid: RN given refers to parent cpd
5'-methylthioadenosine5'-methylthioadenosine: structure

5'-S-methyl-5'-thioadenosine : Adenosine with the hydroxy group at C-5' substituted with a methylthio (methylsulfanyl) group.
thioadenosinealgal metabolite;
Escherichia coli metabolite;
human metabolite;
mouse metabolite;
Saccharomyces cerevisiae metabolite
sitagliptinsitagliptin : A triazolopyrazine that exhibits hypoglycemic activity.triazolopyrazine;
trifluorobenzene
EC 3.4.14.5 (dipeptidyl-peptidase IV) inhibitor;
environmental contaminant;
hypoglycemic agent;
serine proteinase inhibitor;
xenobiotic
tolcaponetolcapone : Benzophenone substituted on one of the phenyl rings at C-3 and C-4 by hydroxy groups and at C-5 by a nitro group, and on the other phenyl ring by a methyl group at C-4. It is an inhibitor of catechol O-methyltransferase.

Tolcapone: A benzophenone and nitrophenol compound that acts as an inhibitor of CATECHOL O-METHYLTRANSFERASE, an enzyme involved in the metabolism of DOPAMINE and LEVODOPA. It is used in the treatment of PARKINSON DISEASE in patients for whom levodopa is ineffective or contraindicated.
2-nitrophenols;
benzophenones;
catechols
antiparkinson drug;
EC 2.1.1.6 (catechol O-methyltransferase) inhibitor
entacaponeentacapone : A monocarboxylic acid amide that is N,N-diethylprop-2-enamide in which the hydrogen at position 2 is substituted by a cyano group and the hydrogen at the 3E position is substituted by a 3,4-dihydroxy-5-nitrophenyl group.

entacapone: structure given in first source
2-nitrophenols;
catechols;
monocarboxylic acid amide;
nitrile
antidyskinesia agent;
antiparkinson drug;
central nervous system drug;
EC 2.1.1.6 (catechol O-methyltransferase) inhibitor
opicaponeopicapone: structure in first sourceoxadiazole;
ring assembly