title: Topical W-7 inhibits ultraviolet radiation-induced melanogenesis in Skh:HR2 pigmented hairless mice.
abstract: We studied the effect of N-(6-aminohexyl)-5-chloro-1-napthalenesulfonamide (W-7) on ultraviolet radiation (UVR)-induced melanogenesis (tanning) in Skh:HR2 pigmented hairless mice. Topically pretreated mice were exposed to subminimal edematogenic as well as edematogenic UVR doses to establish whether W-7-UVR-induced edema prophylaxis allows increased melanogenesis while preventing edema. Ultraviolet light-irradiated vehicle control animals developed visible tans; however, both W-7-treated groups failed to tan. Topical W-7 before UVR exposure inhibited UVR induction of dopa oxidase activity in melanocytes by 49% (P = 0.029) and inhibited UVR-induced deposition of melanin in the epidermis by 88% (P = 0.006). Topical W-7 blocked 23% of the UVR but this blockage could not account for the inhibition of dopa oxidase and melanization. We conclude that, in addition to preventing edema, W-7 inhibits UVR-induced melanogenesis, possibly by affecting Ca(2+)-calmodulin and/or protein kinase C-dependent processes.
authors.affiliation: Department of Biology, University of Memphis, Tennessee, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Dowdy
authors.forename: F A
authors.initials: FA
authors.lastname: Anthony
authors.forename: M E
authors.initials: ME
authors.lastname: Costlow
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors; D002147:Calmodulin / Q000037:antagonists & inhibitors; D004307:Dose-Response Relationship, Radiation; D004487:Edema / Q000209:etiology / Q000517:prevention & control; D004817:Epidermis / Q000378:metabolism; D005260:Female; D007091:Image Processing, Computer-Assisted; D008543:Melanins / Q000378:metabolism / Q000528:radiation effects*; D008544:Melanocytes / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D051379:Mice; D008812:Mice, Hairless; D008815:Mice, Inbred Strains; D014442:Monophenol Monooxygenase / Q000187:drug effects / Q000528:radiation effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D012871:Skin Diseases / Q000209:etiology / Q000517:prevention & control; D012880:Skin Pigmentation / Q000187:drug effects / Q000528:radiation effects*; D013053:Spectrophotometry; D013449:Sulfonamides / Q000008:administration & dosage / Q000494:pharmacology*; D013473:Sunscreening Agents / Q000008:administration & dosage / Q000494:pharmacology*; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D002147:Calmodulin; D008543:Melanins; D013449:Sulfonamides; D013473:Sunscreening Agents; C017967:W 7; D014442:Monophenol Monooxygenase; D011493:Protein Kinase C; D002118:Calcium