NCIt definition : The mesylate salt of a centrally-acting neurokinin 1 (NK1) receptor antagonist with
antidepressant and antiemetic activities. Casopitant competitively binds to and blocks
the activity of the NK-receptor, thereby inhibiting NK1-receptor binding of the endogenous
tachykinin neuropeptide substance P (SP), which may result in antiemetic effects.
SP is found in neurons of vagal afferent fibers innervating the brain-stem nucleus
tractus solitarii and the area postrema, which contains the chemoreceptor trigger
zone (CTZ), and may be elevated in response to chemotherapy. The NK-receptor is a
G-protein receptor coupled to the inositol phosphate signal-transduction pathway and
is found in both the nucleus tractus solitarii and the area postrema.;