Target type: biologicalprocess
The regulated release of dopamine by a cell. Dopamine is a catecholamine and a precursor of adrenaline and noradrenaline. It acts as a neurotransmitter in the central nervous system but it is also produced peripherally and acts as a hormone. [GOC:ef]
Dopamine secretion is a complex process that involves the synthesis, packaging, and release of dopamine, a neurotransmitter that plays a crucial role in various functions, including movement, reward, motivation, and cognition. The process begins in dopamine-producing neurons, known as dopaminergic neurons, which are located in specific areas of the brain, such as the substantia nigra and ventral tegmental area. Here's a detailed breakdown of the process:
1. **Synthesis:** The precursor molecule for dopamine is L-tyrosine, an amino acid that is obtained from the diet or synthesized from phenylalanine. L-tyrosine is transported into the dopaminergic neuron and converted into L-DOPA (L-dihydroxyphenylalanine) by the enzyme tyrosine hydroxylase. L-DOPA is then converted into dopamine by the enzyme aromatic L-amino acid decarboxylase (DOPA decarboxylase).
2. **Packaging:** Once synthesized, dopamine molecules are packaged into small, membrane-bound vesicles within the neuron. These vesicles act as storage containers for dopamine, preventing its premature release and degradation. The packaging process is facilitated by the vesicular monoamine transporter (VMAT2), which transports dopamine from the cytoplasm into the vesicles.
3. **Release:** When a neuron receives an electrical signal, it triggers the release of dopamine from the synaptic vesicles into the synaptic cleft, the small space between the presynaptic neuron and the postsynaptic neuron. This release occurs through a process called exocytosis, where the vesicles fuse with the presynaptic membrane, releasing dopamine into the synaptic cleft. The release of dopamine is regulated by calcium ions, which enter the neuron through voltage-gated calcium channels when the neuron is stimulated.
4. **Reuptake and Degradation:** After dopamine is released, it binds to dopamine receptors on the postsynaptic neuron, triggering various cellular responses. However, dopamine's action in the synaptic cleft is short-lived due to two main processes: reuptake and degradation. Dopamine is reabsorbed back into the presynaptic neuron by a specific transporter protein called the dopamine transporter (DAT), which then repackages it into vesicles for future release. Some dopamine is also broken down by the enzyme monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT), which convert dopamine into inactive metabolites.
5. **Regulation:** The secretion of dopamine is tightly regulated by various factors, including the activity of the dopaminergic neurons themselves, the availability of precursors, the activity of enzymes involved in synthesis and degradation, and the presence of neurotransmitters and hormones that modulate dopamine signaling.
The precise balance of dopamine in the brain is crucial for normal functioning, and disruptions in dopamine secretion can lead to a range of neurological and psychiatric disorders, including Parkinson's disease, schizophrenia, and addiction. Understanding the intricate process of dopamine secretion is essential for developing therapies that target dopamine pathways to treat these conditions.'
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Protein | Definition | Taxonomy |
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Protein-glutamine gamma-glutamyltransferase 2 | A protein-glutamine gamma-glutamyltransferase 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P21980] | Homo sapiens (human) |
Catechol O-methyltransferase | A catechol O-methyltransferase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P21964] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
oxyquinoline | Oxyquinoline: 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. | monohydroxyquinoline | antibacterial agent; antifungal agrochemical; antiseptic drug; iron chelator |
verapamil | 2-(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 | |
1-(2-naphthalenyl)-3-[(phenylmethyl)-propan-2-ylamino]-1-propanone | ZM39923: structure in first source | naphthalenes | |
beta-lapachone | beta-lapachone : A benzochromenone that is 3,4-dihydro-2H-benzo[h]chromene-5,6-dione substituted by geminal methyl groups at position 2. Isolated from Tabebuia avellanedae, it exhibits antineoplastic and anti-inflammatory activities. beta-lapachone: antineoplastic inhibitor of reverse transcriptase, DNA topoisomerase, and DNA polymerase | benzochromenone; orthoquinones | anti-inflammatory agent; antineoplastic agent; plant metabolite |
vitamin k 3 | Vitamin K 3: A synthetic naphthoquinone without the isoprenoid side chain and biological activity, but can be converted to active vitamin K2, menaquinone, after alkylation in vivo. | 1,4-naphthoquinones; vitamin K | angiogenesis inhibitor; antineoplastic agent; EC 3.4.22.69 (SARS coronavirus main proteinase) inhibitor; human urinary metabolite; nutraceutical |
8-hydroxyquinoline-5-sulfonic acid | 8-hydroxyquinoline-5-sulfonic acid: RN given refers to parent cpd | ||
5-bromoisatin | indoles | anticoronaviral agent | |
isatin | tribulin: endogenous MONOAMINE OXIDASE inhibitory activity extractable into ethyl acetate found in brain and many mammalian tissues and fluids; ISATIN is a major component; produced in excess following alcohol withdrawal; | indoledione | EC 1.4.3.4 (monoamine oxidase) inhibitor; plant metabolite |
indirubin | |||
5-Chloro-1H-indole-2,3-dione | indoles | anticoronaviral agent | |
5-iodoisatin | 5-iodoisatin: structure in first source | indoles | anticoronaviral agent |
isoindigotin | isoindigotin: used in treatment of chronic granulocytic leukemia; structure given in first source | ||
n-phenylacrylamide | N-phenylacrylamide: structure in first source | ||
nsc 95397 | 1,4-naphthoquinones | ||
5'-methylthioadenosine | 5'-methylthioadenosine: structure 5'-S-methyl-5'-thioadenosine : Adenosine with the hydroxy group at C-5' substituted with a methylthio (methylsulfanyl) group. | thioadenosine | algal metabolite; Escherichia coli metabolite; human metabolite; mouse metabolite; Saccharomyces cerevisiae metabolite |
ag-213 | tyrphostin 47: inhibits protein-tyrosine kinase activity of EGF-R both in vitro and in living cells; | ||
sitagliptin | sitagliptin : 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 |
tolcapone | tolcapone : 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 |
entacapone | entacapone : 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 |
rottlerin | rottlerin : A chromenol that is 2,2-dimethyl-2H-chromene substituted by hydroxy groups at positions 5 and 7, a 3-acetyl-2,4,6-trihydroxy-5-methylbenzyl group at position 6 and a (1E)-3-oxo-1-phenylprop-1-en-3-yl group at position 8. A potassium channel opener, it is isolated from Mallotus philippensis. rottlerin: an angiogenesis inhibitor; an inhibitor of protein kinase Cdelta (PKCdelta) and calmodulin kinase III; RN refers to (E)-isomer; do not confuse this chalcone with an anthraquinone that is also called rottlerin (RN 481-72-1); | aromatic ketone; benzenetriol; chromenol; enone; methyl ketone | anti-allergic agent; antihypertensive agent; antineoplastic agent; apoptosis inducer; K-ATP channel agonist; metabolite |
gw-5074 | |||
glutaminase | |||
guanylyl imidodiphosphate | guanosine 5'-[beta,gamma-imido]triphosphate : A nucleoside triphosphate analogue that is GTP in which the oxygen atom bridging the beta- to the gamma- phosphate is replaced by a nitrogen atom A non-hydrolyzable analog of GTP, it binds tightly to G-protein in the presence of Mg(2+). Guanylyl Imidodiphosphate: A non-hydrolyzable analog of GTP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It binds tightly to G-protein in the presence of Mg2+. The nucleotide is a potent stimulator of ADENYLYL CYCLASES. | nucleoside triphosphate analogue | |
opicapone | opicapone: structure in first source | oxadiazole; ring assembly |