Parkinson's disease: controlling movement difficulties
Tremors, controlled by spontaneous electrical activity.
In order for dopamine to be released by a dopaminergic neuron, the neuron has to be electrically active. Following a stimulus, the ions which are naturally located outside and inside neurons will go from one side of the neuronal membrane to another and trigger the appearance of an action potential, called a "nervous impulse". This spreads along the axon. When it invades the terminal of a neuron, a neurotransmitter is released. It is this chemical message that has an impact on the excitability of the subsequent neuron. Information is thus transmitted from one neuron to another.