EFFECT OF HYPERBARIC-OXYGEN ON THE IMMUNOREACTIVITY TO SUBSTANCE-P INTHE NASAL-MUCOSA OF CLUSTER HEADACHE PATIENTS

Exposure to hyperbaric oxygen has been shown to be effective in cluste r headache, but the mechanism of the action is still not clear. Primar y nociceptive neurons, containing neuropeptides such as substance P an d particularly those innervating the nasal mucose, could be involved i n the pathogenesis of cluster headache. The present study evaluated th e effect of an exposure to hyperbaric oxygen on the content of substan ce P in the nasal mucosa of patients affected by cluster headache. The results were compared with those observed in another group of cluster headache patients who underwent a placebo procedure. The samples of n asal mucose were analyzed by immunocytochemical methods. A qualitative analysis of the slides was carried out by an operator under ''blinded conditions.'' A marked decrease in the content of immunoreactivity fo r substance P was found in the patients exposed to hyperbaric oxygen. The decrease was statistically significant when compared with the find ings of the placebo procedure. The results of the present study indica te that an influence on the content of peripheral neuropeptides could be involved in the mechanism of action of the beneficial effect of hyp erbaric oxygen in cluster headache.