RESUMO
Forty adult male albino rats [200 +/- 20 g each] were used in this study. Animals were equally divided into 4 groups [n = 10]; normal control [CON] group was intraesophageally [i.o.] administered with distilled water [0.5 mL/d] for 1 week [wk]; L-type calcium-channel blocker [CCB] group that i.o. administered with otilonium [octylonium] bromide [OB, 2 mg/kg rat/d dissolved in 0.5 mL distilled water] for 1 wk; a cold-restraint stress [CRS] group that i.o. administered with distilled water as CON group but also restrained for 3 hs/d at 4- 6 degreeC in individual wire-mesh cylinders for 1 wk; and combined group [CCB+CRS group] that i.o. administered with OB as in CCB group and also restrained as in CRS group. The number of fecal pellets expelled by each animal was counted and examined for its consistency every 30 min for 3 hs, starting at 5 min after the induction of CRS or transporting to individual cages. At the end of the 1 -wk period, each rat was sacrificed by stunning and cervical dislocation, the abdominal cavity was opened along the midline, the stomach, upper segment of small intestine [US], lower segment of small intestine [W and a segment from distal colon [DCS] were rapidly excised and soaked in warm [37 degreeC], carbonated Tyrode s solution. Stomach was further used for measuring the areas of erosion [ulcers] if present, while UIS, LIS and DCS were further used for motility study of both spontaneous and evoked contractility in response to ACh and KCl: CRS produced significant increase the spontaneous motility of the UIS when compared to the CON values. Contractile response to ACh and KCl of both UIS and DCS were also significantly increased by CRS. Also, fecal pellet output was increased significantly by CRS when compared with the corresponding values in CON rats. Moreover, CRS induced gastric ulceration which appeared to be scattered along the mucosa of the stomach, On the other hand, the motility of LIS insignificantly changed by CRS. Administration to OB [L-type CCB] produced significant decrease in spontaneous contractions and contractile responses to ACh and KCl of UIS, LIS and DCS, together with decreased fecal pellets output when compared with the corresponding values in CON rats. Administration to OB to CRS rats reduced significantly both spontaneous and evoked motility in response to ACh and KCl of UIS and DCS, while the LIS did not affect significantly when compared with the corresponding values of non-treated CRS group. Also, OB administration reduced significantly the increased fecal pellet output caused by CRS. On the other hand, OB administration to CRS rats produced significant reduction or almost complete protection of the gastric mucosa from the development of ulceration. It can be concluded that OB [L-CCB] could help in prevention and treatment of GIT motility disorders caused by different stressors as CRS. Also, OB could prevent the development of stress gastric ulceration in different forms of stressors