1997 Volume 73 Issue 3 Pages 255-257
In the guinea pig distal colon, calcitonin gene-related peptide (CGRP, 0.1 30 nM) produced a concentration-dependent inhibition in electrically-evoked nonadrenergic noncholinergic (NANC)contractions and exogenous substance P-induced contractions. Both the inhibitory actions of CGRP were insensitive to human CGRP(8-37) (1-3 μM), a CGRP1 receptor antagonist. These results indicate that in the distal colon, CGRP inhibits electrically-evoked NANC contraction through a postjunctional mechanism, in contrast to our previously described results that CGRP enhances the NANC contraction of guinea pig proximal colon via a prejunctinal mechanism.
