Participation of serotonin in capsaicin-induced mouse ear edema.
We investigated the involvement of serotonin (5-HT) in mouse ear edema induced by topical application of capsaicin (250 micrograms/ear). Application of capsaicin to the ear caused degranulation of mast cells in skin connective tissue. Capsaicin-induced ear edema was significantly inhibited by preadministration of 5-HT2 receptor antagonists such as ketanserin (2 mg/kg, i.v.) and LY 53857 (1 mg/kg, i.v.), but not 5-HT1-, 5-HT3- and 5-HT4-receptor antagonists. Intradermal injection of alpha-methyl 5-HT (5-HT2-receptor agonist) and 5-HT into ear skin produced edema formation more potently than 8-OH-DPAT (5-HT1A agonist) and 2-methyl 5-HT (5-HT3 agonist). 5-HT2 antagonists markedly suppressed the edema response to 5-HT and its receptor agonists, whereas any antagonist for 5-HT1, 5-HT3 and 5-HT4-receptors had no effect. Furthermore, 5-HT2-receptor antagonists partly prevented ear edema in response to substance P (SP), a putative mediator or capsaicin-induced edema, and compound 48/80, a releaser of vasoactive amines form mast cells. These results suggest that 5-HT released from mast cells is partly involved in the development of capsaicin-induced mouse ear edema via 5-HT2 receptors in the ear skin.
Inoue
H
H
Research Laboratory, Minophagen Pharmaceutical Co., Kanagawa, Japan.
Nagata
N
N
Koshihara
Y
Y
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D004427:Ear Diseases / Q000188:drug therapy*; D004487:Edema / Q000139:chemically induced*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*; D013373:Substance P / Q000494:pharmacology
D012701:Serotonin; D013373:Substance P; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D002211:Capsaicin