[(11)C]MK-4232: The First Positron Emission Tomography Tracer for the Calcitonin Gene-Related Peptide Receptor.

Rational modification of the potent calcitonin gene-related peptide (CGRP) receptor antagonist MK-3207 led to a series of analogues with enhanced CNS penetrance and a convenient chemical handle for introduction of a radiolabel. A number of 11C-tracers were synthesized and evaluated in vivo, leading to the identification of [11C]8 ([11C]MK-4232), the first positron emission tomography tracer for the CGRP receptor.