Parkinsonism

The underlying insult causing Parkinson’s dz is in the basal gangion, unique to Parkinson’s is loss of dopaminergic neurons in the substantia nigra.



The distribution of dopamine receptors is extensive throughout the CNS, but when the D1 and D2 receptors are the targets for drug therapy because they are the only ones found in the substantia nigra. If you can get agonist activity of D1 and D2 its good. D4 is in the frontal cortex in the medulla, this will have importance in the anti-psychotic drugs when the major dysfunction has to do with behavior. D5 involves the limbic system, which controls the emotional component of pain. So D4 and D5 become important in treating mental illness. D1/D2 are important in Parkinson’s dz.



They are slow, shuffling, and usually will not move their arms too much. They have motor instability. Help your pt get to the chair and avoid obstacles and anything that causes them to turn suddenly.



The most common motor instability is so-called retropulsion. The pt is unaware that he is leaning backward, and will often step backward involuntarily. This is not drug induced (sedatives and anti-HTN can cause dizziness and loss of balance, this is not the same thing as is seen with Parkinson’s pts). By the way, parkinson’s dz is more common in men than women. High amounts of caffeine produce tremors, but not the same kind as in Parkinson’s pts.

Category: Pharmacology Notes