Substance P in the mouse cornea: effects of chemical and surgical denervation

The substance P content of the cornea of the adult mouse has been determined by radioimmunoassay. Sympathectomy did not reduce corneal substance P levels. However substance P levels were reduced by 42% following surgical denervation and by 80% following neonatal capsaicin treatment, suggesting that corneal substance P is contained in the peripheral terminals of small diameter sensory neurones. In some mice capsaicin treatment reduced corneal sensitivity; it also resulted in marked corneal vascularization. These effects could not be ascribed to the reduction in corneal substance P.