title: Effects of UVB irradiation on epidermal adenylate cyclase responses in vitro: its relation to sunburn cell formation.
abstract: UVB irradiation augmented the beta-adrenergic adenylate cyclase response of pig skin epidermis in vitro. The effect was observed 2-4 h following the irradiation and lasted at least for 48 h. There was no significant difference in cyclic AMP phosphodiesterase activity between control and UVB-irradiated epidermis at lower irradiation dose (150 mJ/cm2), which is the dose of the most marked beta-adrenergic augmentation effect. The augmentation effect was specific to the beta-adrenergic system; adenosine and histamine adenylate cyclase responses were unchanged or decreased depending on the irradiation dose. Histologically, marked sunburn-cell formation was observed following the UVB irradiation. It has been suggested that oxygen intermediates generated by ultraviolet radiation participate in sunburn-cell formation. The addition of superoxide dismutase (SOD) in the incubation medium significantly inhibited sunburn-cell formation. On the other hand, the beta-adrenergic augmentation effect was not affected by the addition of SOD. Other scavengers of oxygen intermediates (catalase, catalase + SOD, xanthine, or mannitol) did not inhibit the UVB-induced beta-adrenergic augmentation effect. Further, superoxide-anion generating systems (hypoxanthine-xanthine oxidase system and acetaldehyde-xanthine oxidase system) revealed no stimulatory effect on the beta-adrenergic response of epidermis. These results indicate that (a) the UVB-induced beta-adrenergic augmentation effect is inherent to skin and does not depend on systemic factors such as inflammatory infiltrates following UVB irradiation; (b) in contrast to sunburn-cell formation, induction of the beta-adrenergic adenylate cyclase response is not directly associated with oxygen intermediates generated by UVB irradiation.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism / Q000528:radiation effects*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D004817:Epidermis / Q000201:enzymology / Q000528:radiation effects*; D005609:Free Radicals; D010100:Oxygen / Q000378:metabolism; D011833:Radiation Injuries, Experimental / Q000201:enzymology / Q000473:pathology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000494:pharmacology; D013552:Swine; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D000975:Antioxidants; D005609:Free Radicals; D011943:Receptors, Adrenergic, beta; D013482:Superoxide Dismutase; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D000262:Adenylyl Cyclases; D010100:Oxygen