Nitric oxide as a chemical link in the generation of pain from veins in humans

Abstract
Thus suggesting NO as a chemical link in nociception. Consistent with this hypothesis, our observations show that neither bradykinin, nor hyperosmolar solutions (a noxious physicochemical stimulus) evoke pain from hand vein segments that have been exposed to the NO-synthase (NOS) inhibitor NG-mono-methyl-L-arginine. An intact NOS pathway is therefore a prerequisite for pain to toe evoked by bradykinin and hyperosmolar solutions from veins, indicating for the first time in humans that vascular pain is mediated by NO. Thus, new directions for research on analgesics may be opened. *Corresponding author: Dr. D. Mndgen-Milles, Institut für Experimentelle Anästhesiologie, Heinrich-Heine-Universität Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany. Tel.: 0211-311-3610; FAX: 0211-311-3954. (Received 3 February 1995; accepted 30 March 1995.) © Lippincott-Raven Publishers....