Agonists of proteinase-activated receptor 1 induce plasma extravasation by a neurogenic mechanism

Lawrence De Garavilla, Nathalie Vergnolle, Steven H. Young, Helena Ennes, Martin Steinhoff, Valeria S. Ossovskaya, Michael R. D'Andrea, Emeran A. Mayer, John L. Wallace, Morley D. Hollenberg, Patricia Andrade-Gordon, Nigel W. Bunnett

Research output: Contribution to journalArticlepeer-review

Abstract

1. Thrombin, generated in the circulation during injury, cleaves proteinase-activated receptor 1 (PAR1) to stimulate plasma extravasation and granulocyte infiltration. However, the mechanism of thrombin-induced inflammation in intact tissues is unknown. We hypothesized that thrombin cleaves PAR1 on sensory nerves to release substance P (SP), which interacts with the neurokinin 1 receptor (NK1R) on endothelial cells to cause plasma extravasation. 2. PAR1 was detected in small diameter neurons known to contain SP in rat dorsal root ganglia by immunohistochemistry and in situ hybridization. 3. Thrombin and the PAR1 agonist TFLLR-NH2 (TF-NH2) increased [Ca2+]i > 50% of cultured neurons (EC50s 24 mu ml-1 and 1.9 μM, respectively), assessed using Fura-2 AM. The PAR1 agonist completely desensitized responses to thrombin, indicating that thrombin stimulates neurons through PAR1. 4. Injection of TF-NH2 into the rat paw stimulated a marked and sustained oedema. An NK1R antagonist and ablation of sensory nerves with capsaicin inhibited oedema by 44% at 1 h and completely by 5 h. 5. In wild-type but not PAR1-/- mice, TF-NH2 stimulated Evans blue extravasation in the bladder, oesophagus, stomach, intestine and pancreas by 2-8 fold. Extravasation in the bladder, oesophagus and stomach was abolished by an NK1R antagonist. 6. Thus, thrombin cleaves PAR1 on primary spinal afferent neurons to release SP, which activates the NK1R on endothelial cells to stimulate gap formation, extravasation of plasma proteins, and oedema. In intact tissues, neurogenic mechanisms are predominantly responsible for PAR1-induced oedema.

Original languageEnglish (US)
Pages (from-to)975-987
Number of pages13
JournalBritish Journal of Pharmacology
Volume133
Issue number7
DOIs
StatePublished - 2001

Keywords

  • Neurogenic inflammation
  • Neurokinin receptors
  • Oedema
  • Proteinase-activated receptor 1
  • Sensory nerves
  • Substance P
  • Thrombin

ASJC Scopus subject areas

  • Pharmacology

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