Ingestion or inhalation of these chemical agents causes irritation and burning in the nasal and oral mucosa and respiratory lining. Headaches have been widely reported to be induced by inhalation of environmental irritants, but it is unclear how these agents produce headache. Stimulation of trigeminal neurons releases CGRP and substance P and induces neurogenic inflammation associated with the pain of migraine. Here we test the hypothesis that activation of TRPA1 receptors is

the mechanistic link between environmental irritants and peptide-mediated neurogenic inflammation. Known TRPA1 agonists and environmental irritants selleck inhibitor stimulate CGRP release from dissociated rat trigeminal ganglia neurons and this release is blocked by a selective TRPA1 antagonist, HC-030031. Further, TRPA1 agonists and environmental irritants increase meningeal blood flow following intranasal administration. Prior dural application of the CGRP antagonist, CGRP(8-37), or intranasal or dural administration of URMC-099 mw HC-030031, blocks the increases in blood flow elicited by environmental irritants. Together these results demonstrate that TRPA1 receptor activation by environmental irritants stimulates CGRP release and increases cerebral blood flow. We suggest that these events contribute

to headache associated with environmental irritants. (C) 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.”
“BACKGROUND: The European Committee for the Validation of Alternative Methods (ECVAM) supported the development of a linear discriminant embryotoxicity prediction model founded on rat whole embryo

culture (Piersma et al. (2004). Altern Lab Anim 32:275-307). Our goals were to (1) assess the accuracy of this model with pharmaceuticals, and (2) see more to use the data to develop a more accurate prediction model. METHODS: Sixty-one chemicals of known in vivo activity were tested. They were part of the ECVAM validation set (N=13), commercially available pharmaceuticals (N=31), and Pfizer chemicals that did not reach the market, but for which developmental toxicity data were available (N=17). They were tested according to the ECVAM procedures. Fifty-seven of these chemicals were used for Random Forest modeling to develop an alternate model with the goal of using surrogate endpoints for simplified assessments and to improve the predictivity of the model. RESULTS: Using part of the ECVAM chemical test set, the ECVAM prediction model was 77% accurate. This approximated what was reported in the validation study (80%; Piersma et al. (2004). Altern Lab Anim 32: 275-307). However, when confronted with novel chemicals, the accuracy of the linear discriminant model dropped to 56%. In an attempt to improve this performance, we used a Random Forest model that provided rankings and confidence estimates.