Calcitonin gene-related peptide desensitizes skeletal muscle arterioles to substance P in vivo.

Calcitonin gene-related peptide (CGRP) was tested for possible interactions with the effects of substance P on rabbit skeletal muscle arterioles in vivo. Both CGRP and substance P dose-dependently increased arteriolar diameter. However, pretreatment with CGRP made the arterioles insensitive to substance P, and also prevented the formation of aggregates of leukocytes and platelets normally seen after substance P. These results suggest that CGRP, in addition to its direct effects, may act as a modulator of the effects of substance P in neurogenic inflammation.