OBJECTIVEThe aim of this study was to observe whether vasoactive intestinal polypeptide (VIP) participated in the attack of trigeminal neuralgia, and to understand further its pathogenetic mechanism.

METHODSSixteen patients were studied. During the attacks the venous blood was sampled from both the external jugular vein and cubital fossa vein ipsilateral to the pain, and after operations the venous blood from the external jugular vein was sampled again, the external jugular vein blood of eleven normal volunteers was collected as the control. Plasma levels of VIP were determined using sensitive radioimmunoassays.

RESULTSDuring the attacks of trigeminal neuralgia the levels of VIP in the external jugular vein blood were significantly higher than that in the cubital fossa vein blood, postoperative external jugular vein blood and the external jugular vein blood of normal volunteers.

CONCLUSIONVIP indeed participates in the attack of trigeminal neuralgia in the local region, the role of VIP may be relating to enhancing the effects of substance P in local neurogenic inflammation.