PT  - JOURNAL ARTICLE
AU  - Leena K. Singh
AU  - William Boucher
AU  - Xinzhu Pang
AU  - Richard Letourneau
AU  - Dimitri Seretakis
AU  - Marlon Green
AU  - Theoharis C. Theoharides
TI  - Potent Mast Cell Degranulation and Vascular Permeability Triggered by Urocortin Through Activation of Corticotropin-Releasing Hormone Receptors
DP  - 1999 Mar 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 1349--1356
VI  - 288
IP  - 3
4099  - http://jpet.aspetjournals.org/content/288/3/1349.short
4100  - http://jpet.aspetjournals.org/content/288/3/1349.full
SO  - J Pharmacol Exp Ther1999 Mar 01; 288
AB  - Urocortin (Ucn) is related to corticotropin-releasing hormone (CRH), and both are released in the brain under stress where they stimulate CRH 1 and 2 receptors (CRHR). Outside the brain, they may have proinflammatory actions through activation of mast cells, which are located perivascularly close to nerve endings and degranulate in response to acute psychological stress. Here, we report that a concentration of intradermal Ucn as low as 10 nM induced dose-dependent rat skin mast cell degranulation and increased vascular permeability. This effect appeared to be equipotent to that of calcitonin gene-related peptide and neurotensin. Ucn-induced skin vasodilation was inhibited by pretreatment with the mast cell stabilizer disodium cromoglycate (cromolyn) and was absent in the mast cell-deficient W/Wv mice. The selective nonpeptide CRH receptor 1 antagonist, antalarmin and the nonselective peptide antagonist astressin both reduced vascular permeability triggered by Ucn but not that by Substance P or histamine. In contrast, the peptide antagonist α-helical CRH-(9–41) reduced the effect of all three. The vasodilatory effect of Ucn was largely inhibited by pretreatment with H1 receptor antagonists, suggesting that histamine is the major mediator involved in vitro. Neuropeptide depletion of sensory neurons, treatment with the ganglionic blocker hexamethonium, or in situ skin infiltration with the local anesthetic lidocaine did not affect Ucn-induced vascular permeability, indicating that its in situ effect was not mediated through the peripheral nervous system. These results indicate that Ucn is one of the most potent triggers of rat mast cell degranulation and skin vascular permeability. This effect of Ucn may explain stress-induced disorders, such as atopic dermatitis or psoriasis, and may lead to new forms of treatment. The American Society for Pharmacology and Experimental Therapeutics