title: Towards Development of a Dermal Pain Model: In Vitro Activation of Rat and Human Transient Receptor Potential Ankyrin Repeat 1 and Safe Dermal Injection of o-Chlorobenzylidene Malononitrile to Rat.
abstract: During clinical development of analgesics, it is important to have access to pharmacologically specific human pain models. o-Chlorobenzylidene malononitrile (CS) is a selective and potent agonist of the transient receptor potential ankyrin repeat 1 (TRPA1), which is a transducer molecule in nociceptors sensing reactive chemical species. While CS has been subject to extensive toxicological investigations in animals and human beings, its effects on intradermal or subcutaneous injection have not previously been reported. We have investigated the potential of CS to be used as an agonist on TRPA1 in human experimental pain studies. A calcium influx assay was used to confirm the capacity of CS to activate TRPA1 with >100,000 times the selectivity over the transient receptor potential vanilloid receptor 1. CS dose-dependently (EC50 0.9 μM) released calcitonin gene-related peptide in rat dorsal root ganglion cultures, supporting involvement in pain signalling. In a local tolerance study, injection of a single intradermal dose of 20 mM CS to rats resulted in superficial, circular crusts at the injection sites after approximately 4 days. The histopathology evaluation revealed a mild, acute inflammatory reaction in the epidermis and dermis at the intradermal CS injection site 1 day after administration. After 14 days, the epidermal epithelium was fully restored. The symptoms were not considered to be adverse, and it is suggested that doses up to 20 μL of 20 mM CS can be safely administered to human beings. In conclusion, our data support development of a CS human dermal pain model.
authors.affiliation: Global Safety Assessment, AstraZeneca R&D, Södertälje, Sweden.
authors.forename: Anita
authors.initials: A
authors.lastname: Annas
authors.affiliation: Global Safety Assessment, AstraZeneca R&D, Södertälje, Sweden.|Medical Products Agency, Uppsala, Sweden.
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Berg
authors.affiliation: Neuroscience, Innovative Medicines CNS/Pain, AstraZeneca R&D, Södertälje, Sweden.|The National Board of Health and Welfare, Stockholm, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Nyman
authors.affiliation: Pharmaceutical Development, Medicines Evaluation CNS/Pain, AstraZeneca R&D, Södertälje, Sweden.|SP Process Development, Södertälje, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Meijer
authors.affiliation: Pharmaceutical Development, Medicines Evaluation CNS/Pain, AstraZeneca R&D, Södertälje, Sweden.
authors.forename: Viveka
authors.initials: V
authors.lastname: Lundgren
authors.affiliation: Neuroscience, Innovative Medicines CNS/Pain, AstraZeneca R&D, Södertälje, Sweden.|Cancer Center Karolinska, Karolinska Institute and Hospital, Stockholm, Sweden.
authors.forename: Bo
authors.initials: B
authors.lastname: Franzén
authors.affiliation: Clinical Sciences, Neuroscience Therapeutic Area, AstraZeneca R&D, Södertälje, Sweden.|Pain Clinic, Karolinska Hospital Huddinge and CLINTEC Karolinska Institute, Stockholm, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Ståhle
mesh_terms: D000818:Animals; D016466:CHO Cells; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D003412:Cricetulus; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007271:Injections, Intradermal; D008297:Male; D009419:Nerve Tissue Proteins / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D059225:Nociception / Q000187:drug effects; D059226:Nociceptive Pain / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D017288:Pain Threshold / Q000187:drug effects; D017208:Rats, Wistar; D012867:Skin / Q000294:innervation*; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels / Q000819:agonists* / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D050051:Transient Receptor Potential Channels / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D009763:o-Chlorobenzylidenemalonitrile / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D015220:Calcium Channels; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050052:TRPC Cation Channels; D050051:Transient Receptor Potential Channels; C480976:Trpa1 protein, rat; D009763:o-Chlorobenzylidenemalonitrile; D015740:Calcitonin Gene-Related Peptide