Abstract:

Objective To investigate the effect of morphine, sufentanil and dezocine on contraction and motor function of intestinal smooth muscle in rats. Methods Isolated small intestine of rats was prepared, and were treated with different concentrations of morphine (5 mg/L, 10 mg/L and 30 mg/L), sufentanil (20 μg/L, 40 μg/L and 120 μg/L) and  dezocine (1.7 mg/L, 3.4 mg/L and 10.2 mg/L) respectively. The contractile tension and frequency of the small intestine smooth muscle of rats were recorded, and the effect of treatment was observed. Thirtytwo SD rats were randomly divided into control group (1 mL normal saline), morphine group (1.04 mg/kg), sufentanil group (2.08 mg/kg) and dezocine group (1.04 mg/kg), and the propulsive motility in intestinal tract was measured after intraperitoneal injection of three drugs in rats. Results After treatment with 10 mg/L and 30 mg/L morphine and 40 μg/L and 120 μg/L sufentanil, the contractile tension of the isolated small intestine smooth muscle of rats significantly increased (P<0.05), while 5 mg/L morphine, 20 μg/L sufentanil and different concentrations of dezocine (1.7 mg/L, 3.4 mg/L and 10.2mg/L) had no significant effect on the contractile tension of the isolated small intestine smooth muscle of rats (P>0.05). Different concentrations of morphine, sufentanil and dezocine had no significant effect on the contractile frequency of the isolated small intestine smooth muscle of rats (P>0.05). Compared with control group, the propulsive distance in intestinal tract significantly decreased after treatment with morphine, sufentanil and dezocine (P<0.05), and there was no significant difference in the propulsive distance among morphine, sufentanil and dezocine groups (P>0.05). Conclusion Morphine, sufentanil and dezocine all have an inhibitory effect on the intestinal motility of rat.

Key words: morphine, sufentanil, dezocine, small intestine smooth muscle, opioid receptor