TY - JOUR
T1 - Enhanced scratching elicited by a pruritogen and an algogen in a mouse model of contact hypersensitivity
AU - Fu, Kai
AU - Qu, Lintao
AU - Shimada, Steven G.
AU - Nie, Hong
AU - LaMotte, Robert H.
N1 - Funding Information:
The work was supported by a grant from the US National Institutes of Health to R.H.L. ( NS014624 ) and a grant from the Chinese National Natural Science Foundation to H.N. (No. 81373993 ). K.F. is the recipient of a scholarship from Jinan University , China. L.Q. is the recipient of a fellowship from the Canadian Institutes of Health Research (CIHR).
PY - 2014/9/5
Y1 - 2014/9/5
N2 - Chemical pruritogens and algogens evoke primarily itch and pain, respectively, when administered to the skin of healthy human subjects. However, the dominant sensory quality elicited by an algesic chemical stimulus may change in patients with chronic itch where bradykinin, elicits itch in addition to pain. Here we tested whether normally pruritic and algesic chemicals evoked abnormal itch- or pain-like behaviors in the mouse after the development of contact hypersensitivity (CHS), an animal model of allergic contact dermatitis. Mice previously sensitized to a hapten (squaric acid dibutylester) applied to the abdomen, exhibited spontaneous itch-like scratching and pain-like wiping directed to the site on the cheek of the CHS elicited by a subsequent challenge with the same hapten. In comparison with responses of control mice, CHS mice exhibited a significant increase in the scratching evoked by bovine adrenal medulla 8-22, a peptide that elicits a histamine-independent itch, but did not alter the scratching to histamine. Bradykinin, an algogen that elicited only wiping in control mice, additionally evoked significant scratching in CHS mice. Thus, within an area of CHS, histamine-independent itch is enhanced and chemically evoked pain is accompanied by itch.
AB - Chemical pruritogens and algogens evoke primarily itch and pain, respectively, when administered to the skin of healthy human subjects. However, the dominant sensory quality elicited by an algesic chemical stimulus may change in patients with chronic itch where bradykinin, elicits itch in addition to pain. Here we tested whether normally pruritic and algesic chemicals evoked abnormal itch- or pain-like behaviors in the mouse after the development of contact hypersensitivity (CHS), an animal model of allergic contact dermatitis. Mice previously sensitized to a hapten (squaric acid dibutylester) applied to the abdomen, exhibited spontaneous itch-like scratching and pain-like wiping directed to the site on the cheek of the CHS elicited by a subsequent challenge with the same hapten. In comparison with responses of control mice, CHS mice exhibited a significant increase in the scratching evoked by bovine adrenal medulla 8-22, a peptide that elicits a histamine-independent itch, but did not alter the scratching to histamine. Bradykinin, an algogen that elicited only wiping in control mice, additionally evoked significant scratching in CHS mice. Thus, within an area of CHS, histamine-independent itch is enhanced and chemically evoked pain is accompanied by itch.
KW - Algogen
KW - Contact hypersensitivity
KW - Itch
KW - Pain
KW - Pruritogen
UR - http://www.scopus.com/inward/record.url?scp=84907598762&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84907598762&partnerID=8YFLogxK
U2 - 10.1016/j.neulet.2014.03.062
DO - 10.1016/j.neulet.2014.03.062
M3 - Comment/debate
C2 - 24704378
AN - SCOPUS:84907598762
VL - 579
SP - 190
EP - 194
JO - Neuroscience Letters
JF - Neuroscience Letters
SN - 0304-3940
ER -