A FLUORESCENCE-BASED METHOD FOR ASSESSING DURAL PROTEIN EXTRAVASATIONINDUCED BY TRIGEMINAL GANGLION STIMULATION

Neurogenic dural inflammation has been proposed as a source of pain du ring migraine. Unilateral electrical stimulation of the trigeminal gan glion causes the ipsilateral release of inflammatory neuropeptides and subsequent dural plasma protein extravasation, a component of neuroge nic inflammation. We measured the amount of protein leaking into the d ural tissue of guinea pigs following trigeminal ganglion stimulation b y exploiting the complexation reaction of endogenous proteins with the fluorescent dye Evans Blue, instead of utilizing exogenous radiolabel ed albumin as commonly done in the literature. The amount of Evans Blu e trapped in dural tissue following electrical stimulation of the trig eminal ganglion was measured using a fluorescence microscope equipped with a spectrophotometer. This method utilized multiple measurements o n each dura sample which resulted in very precise values using a small number of animals per point (n = 3). Sumatriptan and CP-122,288 were found to dose-dependently prevent neurogenic dural extravasation. The potencies of CP-122,288 and sumatriptan were found to be similar to th ose reported in the literature when similar experimental protocols wer e used. (C) 1998 Elsevier Science B.V. All rights reserved.