Neurokinin 1 receptor, IB4 lectin and nitric oxide synthase localizations in whole-mount preparation of the rat meninges following noxious stimulation

Abstract

Distribution and immunocytochemical characterization of the nerve fibers and their terminals in Wistar rats (n=15) meninges were studied by using neurokinin 1 receptor, IB4 lectin and nitric oxide synthase labeling after the application of noxious peripheral stimulation. For immunocytochemistry, free floating specimens were incubated with neurokinin 1 receptor, nitric oxide synthase and IB4 lectin antibodies and then observed with avidin-biotin-peroxidase method. The neuronal markers stained in all unmyelinated nerve fibres throughout the meninges. Neurokinin 1 receptor- and IB4 lectinimmunoreactive nerve fibers were localized in all leptomeningeal compartments, where they terminated close to the subarachnoid space or within the connective tissue, thus suggesting extensive distribution of nerve fibres in the meninges. Neuronal nitric oxide synthase-positive nerve fibers and a prominent mast cell population were seen in the rat leptomeninx and dura. The presence of a significant number of putative nociceptive fibres suggests a possible role for nociceptive function in the context of pathophysiological aspects. The distributions pattern of IB4 lectin binding sites, neurokinin 1 receptor and nitric oxide synthase could be due to the function of particular segments in the pathogenesis of meningeal vascular network.