Calcitonin gene-related peptide (CGRP) mRNA expression in rat dorsal root ganglion cells was measured by polymerase chain reaction after ultraviolet (UV) irradiation of the skin. The aim was to investigate whether a noninvasive peripheral lesion set by UV irradiation influences neuropeptide gene expression thus possibly contributing to the pathophysiology of the UV erythema. Forty-eight hours after irradiation, when the inflammatory response of the skin was at its maximum, there was a decrease in CGRP mRNA levels to 50% of the control values. The results demonstrate that exposure of the peripheral receptive field to noxious UV radiation affects neuropeptide gene expression in primary sensory neurons.