Melatonin maintains mitochondrial membrane potential and attenuates activation of initiator (casp-9) and effector caspases (casp-3/casp-7) and PARP in UVR-exposed HaCaT keratinocytes. - Fischer,T.W.; Zmijewski,M.A.; Wortsman,J.; Slominski,A. (J Pineal Res, 2008)