List friends,
I want to offer a short biochemistry lesson: (from better than a decade o=
f=0Amemory-don't pick me too close). My purpose is to give you a working=
=0Aunderstanding of how the new medicines work.
Dopamine is a chemical messenger between certain ("dopaminergic") nerve c=
ells.=0AIt operates in the synapses (the tiny space that separates commun=
icating=0Anerves).
Between normal cells, part of that dopamine is taken up and reused by the=
=0Asending neuron. Another part is destroyed. Dopamine is broken down i=
n the=0Abody by two enzymes-Mono Amine Oxidase (MAO) and Catachol -O- Met=
hyl=0ATransferase (COMT).
General principle: when something is named an =85ase, it is an enzyme. T=
hese=0Aare usually protein molecules. They often posses interesting chem=
ical and/or=0Amechanical properties They operate at the molecular level.
Selegiline, (Deprenyl) is a selective MAO B (for brain) inhibitor. In th=
e=0Arecommended doses, it does not bother MAO A which destroys dopamine i=
n=0Asynapses outside the brain. The two COMT inhibitors we have now (Tas=
mar is=0Aavailable) are not selective. They decrease dopamine destructio=
n in the whole=0Abody. Fortunately, there is carbidopa (blocks the enzym=
e that turns levodopa=0Ainto dopamine outside the brain) in Sinemet. Thi=
s prevents the accumulation=0Aof dopamine in the body outside the brain. =
Thus, elevated B/P, increased=0Aheart rate and other symptoms of excess =
dopamine do not have to be a problem.
Summary:
1 Dopamine is broken down two ways: MAO and COMT
2 Deprenyl and Tasmar block these enzymes, respectively
3 The net effect is that of more dopamine.
4 Tasmar operates outside the brain as well as in the brain
If you understand how this works you can understand how to use these new=
=0Amedicines. I prefer very slow changes. Hope you find this helpful.
Regards,
WHH 54/18
