Action of Dopamine
Silvia Helena Cardoso, PhD and Renato
M. E. Sabbatini, PhD
André Luis Malavazzi (art
and animation)
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Dopamine (shown in red) is a neurotransmitter, a substance synthesized by certain neurons in parts of the brain which are responsible, among others, for motivation and pleasure. After being synthesized, it is stored inside special little bags, named synaptic vesicles (in green). When an electric impulse arrives at the tip of the nerve terminal, these vesicles move into the presynaptic membrane of the neuron and discharge their contents of dopamine into the synaptic gap. The dopamine molecules traverse this gap and attach themselves to specific receptors (dopaminergic receptors) situated in the outer surface of the cell membrane of the following neuron (post-synaptic neuron). This provokes a series of reactions in the neuron, such as the inflow and outflow of some ions, and the release or inhibition of some enzymes. After being released from the dopaminergic receptors, the free dopamine molecules are taken up again by the presynaptic button, by means of so-called dopamine transport sites.
