Agonist (Parkinson’s disease)

A drug or substance that acts as a neurotransmitter. Such a substance sometimes is called a receptor agonist. A dopamine agonist taken to treat the symptoms of Parkinson’s disease, for example, activates dopamine receptors in the brain, binding with them in the same manner as does dopamine. The binding is not as strong or as comprehensive as that of the natural neurotrans-mitter, however, so that effect is more limited. This can be an advantage in a therapeutic context, because an agonist can be used to target a specific receptor to minimize adverse effects that would result if all receptors sensitive to the natural neuro-transmitter were activated.