Two studies, one on UK patients, and another on Italian patients, suggest that two types of drugs for treating Parkinson's disease may be causing leaky heart valves. The drugs are the ergot-derived dopamine receptors, Permax and Dostinex. The two studies conclude that the risk of developing clinically important valve regurgitation is significantly greater in patients on Permax or Dostinex. They suggest this information should form part of the risk versus potential benefit decision when prescribing such drugs in the future.
Dopamine-receptors play an important role in the brain's ability to learn and control movement. They are special proteins that lie between the inner and outer layer of the membrane around brain and other nerve cells. There are five types of dopamine receptors, each type playing a different role in controlling the response of the cell to the arrival of a dopamine neurotransmitter molecule.
Dopamine is a natural chemical produced in the brain. It does not cross the blood brain barrier, so taking a dose of dopamine would have no effect on the brain. That is why drugs such as dopamine receptor agonists and antagonists are used to control the action of dopamine. However, because dopamine has a number of roles, for instance it is also a hormone, drugs that behave like it will also interfere in these other processes.
