Dopamine

The dopamine is a Neurotransmetteur pertaining to the Catécholamine S and thus resulting from the Amino-acid Tyrosine.

It is the precursor of the Adrénaline, of the Noradrénaline.

Physiological functions

In the peripheral Nervous system, she plays the circulatory part of Analeptique (stimulating functions ensuring blood circulation).

On the level of the central Nervous system (SNC) it has an effect overall stimulant. It is implied in the phenomena of dependences via the Reward system. For example, the Cocaïne causes an inversion of the operation of the system of Recapture dopamine which is charged to decrease its action. The Nicotine causes also an increase in the dopaminergique transmission.

Moreover, it is implied in the phenomenon of control of the driving functions. The Parkinson's disease is a disease whose cause is the degeneration of a producing group of neurons of the dopamine.

It is also implied in the cerebral zone not included in the barrier hematoencephalic responsible for the reflex of vomiting, which explains the antiemetic effect of the Neuroleptiques (antagonistic dopaminergique).

The regular practice of a sport makes it possible to increase the natural secretion of dopamine…

It is also implied in TDAH. The problem of capture of Dopamine by the Synapse S is the cause of the TDAH, Trouble of the attention and the hyper activities.

It is especially the precursor of the Parkinson's disease because it starts pertubations neurologigues.

Physiology

The action of the dopamine is médiée by its post-synaptic receiver. There exist 4 types of receivers to the dopamine: the receivers D1, D2, D3 and D4.

Medical use

In perfusion continues, it is a tonic which accelerates the heart rate. It makes it possible to maintain the blood Pressure and the cardiac flow among patients in certain cases of states of shock.

With moderated amount, it involves a vasoconstriction Veine uses helping with the maintenance of the blood Pressure. It also involves a vasodilatation of the renal Artère S making it possible to preserve a Diurèse .

With stronger amount, the effects on the cardiac contraction are counterbalanced by occurred of a Tachycardie, even of Troubles of the cardiac rhythm. A derivative, the Dobutamine, presenting in an attenuated way these side effects, is then preferentially used.

Treatments

To treat diseases with dopaminergique deficit, there is recourse has several types of treatments.

The molecules acting on the phenomenon of recaptures dopamine

One classifies in this group the tricyclic ones, which inhibits the conveyers of amines of the presynaptic membrane. The tricyclic ones are not specific of the conveyer of dopamine (DAT), they inhibit also the conveyers of serotonin, noradrenalin, etc…

Molecules acting on the synaptic phenomenon of degradation of the dopamine

One classifies in this group IMAO, inhibiters of the Monoamine oxydase (MAO).

Seek

  • 2007. The study of the coal titmouses once again comes to confirm the studies of Bart Kempenaers, which evoked the fact that an increase in Concentration in Récepteur D4 of the Dopamine in the Cerveau went hand in hand with an increase in curiosity in the animal.

See too

  • Assumption of the dopamine in dopaminergique schizophrenia
  • System
  • Biochemistry off Parkinson' S Disease

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