AIM:To investigate the effect of L-NAME on nitric oxide andgastrointestinal motility alterations in cirrhotic rats.METHODS:Rats with cirrhosis induced by carbontetrachloride were randomly divided into two groups,one(n=13)receiving 0.5 mg·kg~(-1)per day of N~G-nitro-L-argininemethyl ester(L-NAME),a nitric oxide synthase inhibitor,for 10 days,whereas the other group(n=13)and control(n=10)rats were administrated the same volume of 9 g·L~(-1)saline.Half gastric emptying time and 2 h residual rate weremeasured by SPECT,using ~(99)m Tc-DTPA-labeled bariumsulfate as test meal.Gastrointestinal transition time wesrecorded simultaneously.Serum concentration of nitrcoxide(NO)was determined by the kinetic cadmiu■reduction and colorimetric methods.ImmunohistochemicalSABC method was used to observe the expression anddistribution of three types of nitric oxide synthase(NOS)isoforms in the rat gastrointestinal tract.Western blot wasused to detect expression of gastrointestinal NOS isoforms.RESULTS:Half gastric emptying time and trans-gastrointestinal time were significantly prolonged(124.0±26.4min;33.7±8.9 min;72.1±15.3min;P<0.01),(12.4±0.5h;9.5±0.3h;8.2±0.8 h;P<0.01),2h residual rate wasraised in cirrhotic rats than in controls and cirrhotic ratstreated with L-NAME(54.9±7.6 %,13.7±3.2 %,34.9±10.3%,P<0.01).Serum concentration of NO was significantlyincreased in cirrhotic rats than in the other groups(8.20±2.48)μmol·L~(-1),(5.94±1.07)μmol·L~(-1),and control(5.55±1.60)μmol·L~(-1),P<0.01.NOS staining intensities which weremainly located in the gastrointestinal tissues were markedlylower in cirrhotic rats than in the controls and cirrhotic ratsafter treated with L-NAME.CONCLUSION: Gastrointestinal motility was remarkably inhibited in cirrhotic rats, which could be alleviated by L-NAME. Nitric oxide may play an important role in the inhibition of gastrointestinal motility in cirrhotic rats. AIM: To investigate the effect of L-NAME on nitric oxide andgastrointestinal motility alterations in cirrhotic rats. METHODS: Rats with cirrhosis induced by carbontetrachloride were randomly divided into two groups, one (n = 13) receiving 0.5 mg · kg -1 ) per day of N ~ G-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor for 10 days, while the other group (n = 13) and control The same volume of 9 g · L -1 saline.Half gastric emptying time and 2 h residual rate were measured by SPECT, using ~ (99) m Tc-DTPA-labeled bariumsulfate as test meal. Gastrointestinal transition time wesrecorded simultaneously. concentration of nitrcoxide (NO) was determined by the kinetic cadmiu ■ reduction and colorimetric methods. Immunohistochemical SAABC method was used to observe the expression and distribution of three types of nitric oxide synthase (NOS) isoforms in the rat gastrointestinal tract. Western blot wasused to detect expression of gastrointestinal NOS isoforms.RESULTS : Half gastric emptying time and trans-gastrointestinal time were significantly prolonged (124.0 ± 26.4 min; 33.7 ± 8.9 min; 72.1 ± 15.3 min; P <0.01), (12.4 ± 0.5 h; 9.5 ± 0.3 h; 8.2 ± 0.8 h; P <0.01), 2h residual rate wasraised in cirrhotic rats than in controls and cirrhotic ratstreated with L-NAME (54.9 ± 7.6%, 13.7 ± 3.2%, 34.9 ± 10.3%, P <0.01) .Serum concentration of NO was significantly increased in (5.20 ± 2.48) μmol·L -1, (5.94 ± 1.07) μmol·L -1, and control (5.55 ± 1.60) μmol·L -1, respectively. , P <0.01.NOS staining intensities which weremainly located in the gastrointestinal tissues were markedlylower in cirrhotic rats than in the controls and cirrhotic ratsafter treated with L-NAME.CONCLUSION: Gastrointestinal motility was remarkably inhibited in cirrhotic rats, which could be alleviated by L -NAME. Nitric oxide may play an important role in the inhibition of gastrointestinal motility in cirrhotic rats.