Cisapride is an orally administered prokinetic agent which facilitates or restores motility through the length of the gastrointestinal tract. It has been widely used in adult and ped, patients with reflux disease and functional dyspepsia. GER is often seen in premature infants with apnea or BPD, and cisapride is often prescribe in these infants. Because embryonic respiratory tract originates from foregut and shares the same innervation with gastrointestinal tract, it is very probable that cisapride may induce some tonic changes in airway smooth muscle. No study on this aspect has been done previously.
The effect of cisapride on the contractile response of tracheal smooth muscle to electrical field stimulation (EFS) was studied on male Dunkin-Hartley guinea pigs. The trachea segment was suspended between platinum ring electrodes in 5 ml organ baths coniaining Krebs solution gassed with 5% CO2 in O2. In proliminary studies, it was found that stimuli of 90 Vat 50Hz to be maximal. This condition was used throughout the study. Atropine (0.1uM) could abolish the contractile response totally. Cisapride was observed to eause a relaxation of the electrically stimulated GP trachea. The degree of reduction in contractile response increased with increased concentration of cisapride (15.4 ± 10.7, 17.6 ± 7.5, 37.7± 5.6 and 37.5 ± 11.2% for a concentration of 10-6 M, 3×10-6M, 10-5 and 3×10-5M, respectively). The mechanism of relaxation caused by cisapride and its clinical implication remain to be further investigated.
