Hi, I’m Doctor Shukle. We’re going to cover pharmacology of
Parkinson’s disease in this lecture.
Let’s go over some basics of the dopamine hypothesis in the
treatment of disease.
Now, we know that there’s an association of reduced dopamine
and dopamine levels in patients who have Parkinson’s
So, by increasing the amount of dopamine in those areas, we
treat Parkinson’s disease
and we make the symptoms less obvious.
Unfortunately, when we increase the amount of dopamine,
we also increase the risk of schizophrenia and other
psychosis type behaviors
but in order to treat those psychosis behaviors, we have to
reduce the amount of dopamine in the brain
and of course, you have a cycle.
So, you can see that dopamine is integral to the disease
process of both Parkinson’s disease
and schizophrenia and psychosis,
so, we have to strike a balance between the side effects of
our medications in both classes of illnesses
and the beneficial effects of both classes of drugs.
What we’re going to look at is just how these drugs are used
to treat both
Parkinson’s disease and the dyskinesias or hypokinesias by
reducing the levels of dopamine or rate of dopamine
We also will look at the way that these drugs are used to
and hyperactivity by increasing the levels of dopamine or
In order to understand that, we’ll take a look at all of
these drugs and see how they work in individuality.
Now, one thing that I wanna go over is how these drugs are
working at the level of the brain.
So, let’s take a look at my brain diagram. We have four
major pathways that I want to talk about.
First, is the nigrostriatal tract.
There are extra parametal cells there that result in what we
call extraparametal function
and by increasing the amount of dopamine in this region, you
improve Parkinsonian symptoms.
We have the mesocortical and mesolimbic tracts. The
mesocortical tract is associated with apathy
and lack of emotion and the mesolimbic tract is associated
with hallucinations and delusions.
We also have the tuberoinfundibular tract.
You can have more inhibition of prolactin release by
increasing your dopamine levels
and change the levels of prolactin that you have.
Finally, you have something called the chemoreceptor trigger
zone or chemoreceptor zone.
It’s also abbreviated to CTZ, so, if you ever see CTZ, this
is what we’re talking about.
This is the vomiting center of the brain. It’s associated by
- with increasing anorexia, nausea, and vomiting.