Long-term superior cervical sympathectomy induces mast cell hyperplasia and increases histamine and serotonin content in the rat dura mater

Nerve fibres and mast cells are often described in close morphological and functional interactions in various organs such as the dura mater. The respe ctive roles of mast cell activation and sympathetic impairment in cluster h eadache and migraine attacks have been repeatedly suggested. We have thus i nvestigated the long-term effects of sympathectomy on mast cell morphology and content in the rat dura mater. Fifteen to 60 days after either sham, un ilateral or bilateral superior cervical ganglionectomy, dura were removed f or either histochemical or biochemical analysis. In the first case, they we re fixed and mast cell heparin was stained by fluorescein isothiocyanate-co njugated avidin. Microscopic examination was followed by digital acquisitio ns using a tomographic process to assess mast cell density in the whole dep th of the dura mater. Unilateral ganglionectomy induced a progressive and s ignificant increase in mast cell density 15-60 days post-surgery in contral ateral hemi-dura and 30 days postsurgery in ipsilateral hemi-dura. This inc rease was significant in both dura 60 days after bilateral ganglionectomy. Following perfusion with saline, we also examined the content of histamine and serotonin, pre-formed amines stored in mast cell granules. Biochemical analysis of dura serotonin and histamine content using high-pressure liquid chromatography and radioenzymatic assays, respectively, revealed under all conditions :a serotonin tissue concentration lower than that of histamine. After sham ganglionectomy, the dura serotonin content increased from 15 to 60 days post-surgery, whereas the histamine content remained stable over t he same period. After unilateral ganglionectomy, the histamine content incr eased progressively and significantly 30-60 days post-surgery in both hemi- dura, whereas the serotonin content became significantly different from tha t of sham only 60 days post-surgery in the ipsilateral dura. After bilatera l ganglionectomy, the histamine level significantly increased in both hemid ura 15-60 days post-surgery, whereas the serotonin level had significantly increased at 60 days post-surgery. These results clearly demonstrate, for the first time, a long-term trophic effect of sympathetic nerve degeneration on mast cells in the dura mater. S ince mast cell activation has been described previously on the painful side of cluster headache patients during attack periods, we propose that the sy mpathetic impairment reported in these patients could be prominent, directl y or indirectly inducing mast cell hyperplasia and changes in amine content s in the tissue concerned. (C) 2000 IBRO. Published by Elsevier Science Ltd .