Isradipine slows Parkinson's disease

Researchers at Northwestern University's Feinberg School of Medicine, in Illinois, USA, say that isradipine, the active component in a wide range of hypertension and stroke medications, including Reliant Pharmaceuticals' DynaCirc, slows and may even halt the progression of Parkinson's disease. The work, which was conducted by a team led by James Surmeier, the university's Nathan Smith Davis professor and chair of physiology, showed that the agent rejuvenates the deteriorating dopamine neurons that are characteristic of the disease.

Current PD therapies utilize L-dopa which relieves many disease symptoms by increasing the availability of the neurotransmitter dopamine. L-dopa becomes less effective over time, however, requiring larger doses that are associated with side effects such as involuntary movements to achieve the same therapeutic benefits.

Prof Surmeier's group noticed that, in early life, mouse neurons rely on sodium channels to mediate signal transduction, whereas in older mice this role is taken over by calcium, which accumulates within the cells eventually leading to death. The team implanted time-release isradipine capsules into mice that had recently reached adulthood, before introducing the neurotoxin MPTP. The results showed that, after five weeks, mice injected with just MPTP were demonstrating the first symptoms of PD, whereas those that received isradipine and MPTP were as healthy as animals in the control group.