Reaction time and replenishment time of SP and CGRP after incision in rat skin

Background. the skin neurogenic inflammation is mainly related to Substance P (SP) and Calcitonin Gene-related Peptide (CGRP). There is no data on their availability in the dynamics of skin nerve endings, concerning their release and replenishment after a nociceptive stimulus, so this was investigated. Materials and methods. 25 rats were randomly distributed in 5 groups. the animals of the control group (CG) determined the baseline levels of neuropeptides in the skin. the groups S0 and S30 did not receive any cutaneous stimulus at 30 and 60 minutes, respectively. in the group S1, an incision stimulus was made at 30 minutes. in the group S31, a nociceptive stimulus was performed by subdermal scratching at 30 minutes and, at 60 minutes, the incision stimulus was carried out in the same location (nociceptive hyperstimulation). the skin samples of the other animals were harvested from the back 1 minute after their death. SP, pro-CGRP and CGRP were quantified by Western Blotting. Results. the incision stimulus released SP, S1 compared to S0 (p < 0.05) detected in the first minute, and the replenishment time was more than 30 minutes. Also, it cleaved pro-CGRP, S1 compared to S31 (p < 0.05) in the first minute, and its replenishment time less than 30 minutes. Release of CGRP was not detected. Conclusion. the incision released SP already detected in the first minute; its replenishment time is more than 30 minutes. the incision decreased pro-CGRP, also detected in the first minute; and its replenishment time is less than 30 minutes.