Intradermal cholinergic agonists induce itch-associated response via M3 muscarinic acetylcholine receptors in mice.
In the present study, we examined whether cholinergic agonists would elicit an itch-associated response in mice. When mice were given an intradermal injection of carbachol (1-10 nmol) or bethanechol (0.3-100 nmol) into the rostral back, they showed the dose-dependent increase of scratching. Nicotine (1-10 nmol) showed no effect. Pretreatment with naloxone, but not with terfenadine, significantly suppressed the carbachol-induced scratching. When intradermally co-injected with carbachol, atropine and 4-DAMP but neither methoctramine nor pancuronium significantly inhibited the carbachol-induced scratching. Muscarinic agonists are suggested to produce itch through activation of M3 muscarinic receptors in the skin.
Miyamoto
Takayuki
T
Department of Applied Pharmacology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Nojima
Hiroshi
H
Kuraishi
Yasushi
Y
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D007271:Injections, Intradermal; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018721:Muscarinic Agonists / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D011537:Pruritus / Q000139:chemically induced* / Q000523:psychology; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic / Q000187:drug effects*
D018679:Cholinergic Agonists; D006634:Histamine H1 Antagonists; D018721:Muscarinic Agonists; D009292:Narcotic Antagonists; D018722:Nicotinic Agonists; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic; D002217:Carbachol