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Many PWP have said that their PD developed in a period of extreme stress. The following article in the New Scientist 7th December reports research which demonstrates that stress can cause the blood brain barrier to become more permeable to toxins. Interesting........ STRESS LEAVES THE BRAIN WIDE OPEN TO DRUGS Stress may leave the brain vulnerable to drugs and poisonous substances by making its protective shield, the blood-brain barrier more permeable. Israeli researchers believe this could explain some of the mysterious symptoms suffered by veterans of the Gulf War. Alon Friedman and his colleages at Tel-Aviv University and the Hebrew University of Jerusalem found that the brains of laboratory mice that were under stress could take up drugs and other substances from the blood up to 100 times as readily as the brains of unstressed mice. The researchers began their experiments on mice after an earlier study had uncovered some surprising effects in Israeli soldiers who had fought in the Gulf War. The soldiers had been given the drug Pyridostigmine to protect them against the effects of nerve gas. The drug binds temporarily to an enzyme called acetylcholinesterase, which nerve gases have been designed to destroy. The enzyme "mops up" a neurotransmitter, or messenger chemical, called acetylcholine after a nerve cell fires.. If the enzyme is destroyed and the aceylcholine is not removed the nerves go haywire. The drug is designed to bind to the enzyme which protects it from the nerve gas. Until this study, researchers believed that pyridostigmine could not cross the blood-brain barrier. But in the soldiers, there were strong signs that it did: they suffered more than three times as frequently as expected from side effects that involve the central nervous system, such as headaches and drowsiness. In the experiments on mice that were under stres, Friedman's team found that the amount of pyridostigmine needed to halve the activity of the acetylcholinesterase was just 1 percent of the dose needed to produce the same effect in unstresed mice. He also found that two other substances - plasmid DNA and a blue dye - could reach the brains of stressed mice at one tenth the dose needed for unstressed mice. Finally, Friedman re-examined the effects of pyridostigmine in humans. He found that in contrast to the earlier wartime study using soldiers, a peacetime group of more relaxed volunteers seemed to suffer only side effects that involved their peripheral nervous system, such as sweating and diarrrhoea. The pyridostigmine was not getting through to their brains. The results are published in Nature Medicine vol2 p1382. No one yet knows exactly how stress has this effect on the blood-brain barrier. "The membrane may become more diffuse or porous" suggests Israel Hanin of Loyola University of Chicago. But if scientists can learn exactly how the blood-brain barrier is made more porous, they may eventually be able to manipulate it to improve the delivery of drugs to the brain, he says. In the meantime, tests of new drugs should include a trial of their effects under stressful conditions, he argues. ----------------------------------------------- Nigel Cockle -------------------------------------------------------------- E-mail [log in to unmask] Mail 59 Norley Road, Cuddington, Northwich, CW8 2JY, UK Telephone (44) 1606 882150 --------------------------------------------------------------