Effects of subcutaneous carbon dioxide on calcitonin gene related peptide and substance P secretion in rat skin.

Purpose: To investigate the subcutaneous injection of carbon dioxide (CO2) on neuropeptides Calcitonin Gene-Related Peptide (CGRP) and Substance P (SP) secretion in rat skin.

Methods: Fifty-six Wistar-EPM rats were distributed in two groups: one for CGRP analysis, the other for SP analysis. Each group was subdivided into four subgroups: control (Cont), control with needle (ContNd), CO2 injection (CO2Inj) and atmospheric air injection (AirInj) - with seven animals each.