Calcitonin gene regulatory peptide I precursor, CGRPI of 128 aas and 1 - 3 TMSs. CGRP induces vasodilation, dilating a variety of vessels including the coronary, cerebral and systemic vasculature. Its abundance in the CNS points toward a neurotransmitter or neuromodulator role (Kitamura et al. 1992). It also elevates platelet cAMP and elevates calcium while polarizing the membrane potential by both cAMP-independent and -dependent mechanisms (Burns et al. 2004).