title: Analgesic effects of botulinum neurotoxin type A in a model of allyl isothiocyanate- and capsaicin-induced pain in mice.
abstract: We evaluate analgesic effects of BoNT/A in relation to the two main transient receptor potentials (TRP), the vanilloid 1 (TRPV1) and the ankyrin 1 (TRPA1), having a role in migraine pain. BoNT/A (15 pg/mouse) was injected in the inner side of the medial part of hindlimb thigh of mice, where the superficial branch of femoral artery is located. We chosen this vascular structure because it is similar to other vascular structures, such as the temporal superficial artery, whose perivascular nociceptive fibres probably contributes to migraine pain. After an interval, ranging from 7 to 30 days, capsaicin (agonist of TRPV1) or allyl isothiocyanate (AITC; agonist of TRPA1) were injected in the same region previously treated with BoNT/A and nocifensive response to chemicals-induced pain was recorded. In absence of BoNT/A, capsaicin and AITC induced extensive nocifensive response, with a markedly different temporal profile: capsaicin induced maximal pain during the first 5 min, while AITC induced maximal pain at 15-30 min after injection. Pretreatment with BoNT/A markedly reduced both the capsaicin- and AITC-induced pain for at least 21 days. These data suggest a long lasting analgesic effect of BoNT/A exerted via prevention of responsiveness of TRPV1 and TRPA1 toward their respective agonists.
authors.affiliation: CNR - National Research Council of Italy, Institute of Cell Biology and Neurobiology, Roma, Italy; IRCCS Santa Lucia Foundation, Roma, Italy. Electronic address: siro.luvisetto@cnr.it.
authors.forename: Siro
authors.initials: S
authors.lastname: Luvisetto
authors.affiliation: CNR - National Research Council of Italy, Institute of Cell Biology and Neurobiology, Roma, Italy; IRCCS Santa Lucia Foundation, Roma, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Vacca
authors.affiliation: Child Neuropsychiatry Clinic, AOU, University of Cagliari, Cagliari, Italy. Electronic address: cianchet@unica.it.
authors.forename: Carlo
authors.initials: C
authors.lastname: Cianchetti
mesh_terms: D000700:Analgesics / Q000627:therapeutic use*; D000818:Animals; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D002211:Capsaicin; D017879:Isothiocyanates; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy*
chemical_list: D000700:Analgesics; D017879:Isothiocyanates; C004471:allyl isothiocyanate; D019274:Botulinum Toxins, Type A; C545476:incobotulinumtoxinA; D002211:Capsaicin
keywords: Allyl isothiocyanate; Behavior; Botulinum; Capsaicin; TRPA1; TRPV1