Existing treatment for the Parkinson's disease improves motion behaviour of patients, but do not protect their neurons from deterioration and death. This means these drugs eliminate sysmptoms, but don't really cure the disease. Russian researchers currently work on a treating agent, which can prevent neuros from dying, and are testing the drug.

The Parkinson's disease is known to affect nervous system of a patient - it causes death of neurons, which produce dopamine, a neuromediating substance. A majority of these neutrons is situated in brain's region, known as substantia nigra. One, suffering from the Parkinson's disease, feels difficulty in controlling his movements and keeping the balance.

Numerous studies demonstrate that Parkinson's disease has a characteristic feature - concentration of a growth factor, which regulates growth of nervous fibers, drops dramatically. Researchers from the science and research Institute of Pharmacology (Russian academy of sciences) have synthesized several short peptides, which showed the same effect as abovementioned growth factor. Moreover, they have already tested these peptides on a laboratory culture of neurvous cells, which were grown on a special nutrient medium. After tests they have selected GK-2 peptide, which appeared to be the best protector for neuron cells.

Next stage of research was performed on laboratory animals - mice and rats. Aim of the first experiment was showing that GK-2 peptide didn't affect motion behaviour of healthy rats in some way. The following stage consisted of a study how the drug affected ability of animals to control their movements, in other words, length of catalepsy. Catalepsy is a nervous condition, during which all muscles get rigid, and posture can be kept for almost infinite amount of time. This condition can be intentionally created by means of a drug, called haloperidol. After injection rats were placed on a plastic stand in a posture, which was not common for a healthy animal. Rats with induced catalepsy kept the posture for 45 seconds, however, intraperitoneal injection of GK-2 peptide 24 hours before haloperidol prevented development of unnatural nervous condition of catalepsy. In this cas, rats kept the posture for only 3-4 seconds.

Neurotoxin MPTP (1-methyl-4-phenyl-tetrahydropyridine) is commonly used to simulate symptoms of Parkinson's disease. MPTP causes degeneration of neurons in a midbrain structure, known as substantia nigra. The neurotoxin acts very fast, with symptoms of the disease appearing 2-3 minutes after injections - rats stop moving and exploring. Rats, which received injections of GK-2 peptide 24 hours before the toxin, were much more active. These experiments helped scientists conclude that GK-2 peptide protects neurons for degeneration.

The peptide was also tested on other regions of brain. The substance was experimentally shown to eliminate destructive effects of another compound - 6-oxy-dopamine. Further investigation will show whether GK-2 peptide is suitable for treating human beings.

Source: Science & Technologies

Anna Kizilova