THE TRIGEMINAL NERVE AND AUGMENTATION OF REGIONAL CEREBRAL BLOOD-FLOWDURING EXPERIMENTAL BACTERIAL-MENINGITIS

We investigated whether trigeminal nerve fibers contribute to enhanced regional cerebral blood flow (rCBF) in a rat model of experimental ba cterial meningitis. rCBF was measured continuously for 6 h by laser Do ppler flowmetry through thinned bone over the frontal cortex. Meningit is was induced with pneumococcal cell wall components and confirmed by a significant increase of (a) leukocytes within the cerebrospinal flu id, (b) brain water content, (c) intracranial pressure and (d) rCBF. T he increase of rCBF was significantly attenuated (p < 0.05) at 3, 4, 5 , and 6 h in animals after a chronic (200 +/- 21% versus 138 +/- 13% a t 6 h on the intact and denervated sides, respectively) but not after an acute section of the nasociliary branch of the trigeminal nerve. We conclude that elevations in blood flow during the early phase of bact erial meningitis are mediated in part by the trigeminal nerve, probabl y by local perivascular release of neuropeptides from afferent axons i nnervating the meninges.