Antisecretory effect of prescribed appetite stimulator drug cyproheptadine in rat intestine

Cyproheptadine (Cph) is an antiserotoninergic and antihistaminergic agent with alpha-blocking activity and central sedative effect. Cph has been found to be effective in stimulating appetite, but to our knowledge, its direct effects on the intestine have not been documented. We aimed to assess the antisecretory effects of Cph in rat proximal colon using Ussing chambers' technique. In basal and serotonin (5-HT)-stimulated conditions, Cph induced a dose-dependent reduction in short-circuit current (Isc). This effect was different in fed vs. fasted rats (EC50=1.9x10(-5)m and 4.9x10(-5)m, respectively). As expected, Cph induced a marked dose-dependent rightward shift of the concentration-response curve to 5-HT (pA(2)=5.4). The effect of Cph was found to be close to that of antisecretory agents in the following sequence: peptide YY>somatostatin>clonidine>Cph>C7-sorbin. To our knowledge, this is the first demonstration that Cph has a direct effect on the inhibition of electrogenic ionic secretion in intestinal epithelium in vitro. Our results indicate that Cph can modulate the intestinal transport of electrolytes and provide a new insight into the peripheral effects of this drug, which is frequently prescribed as appetite stimulator in developing countries.