AIM: To investigate the effect of L-NAME on
nitric oxide and
gastrointestinal motility alterations in cirrhotic rats. METHODS: Rats with
cirrhosis induced by
carbon tetrachloride were
randomly divided into two groups, one n =13 receiving 0.5mg.kg(-1) per day of N(G)-nitro-L-arginine
methyl 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 9g.L(-1) saline. Half
gastric emptying time and 2h residual rate were measured by
SPECT, using (99m)Tc-DTPA-labeled
barium sulfate as test meal.
Gastrointestinal transition time was recorded simultaneously. Serum concentration of
nitric oxide (NO) was determined by the kinetic
cadmium reduction and colorimetric methods.
Immunohistochemical SABC 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 was used 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 +/- 0.5h; 9.5 +/- 0.
3h; 8.2 +/- 0.8h; P<0.01), 2h residual rate was raised in cirrhotic rats than in controls and cirrhotic rats treated 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 cirrhotic rats than in the other groups (8.20 +/- 2.48) micromol.L(-1), (5.94 +/-1.07) micromol.L(-1) and control (5.66 +/- 1.60 micromol.L(-1), P<0.01. NOS
staining intensities which were mainly located in the
gastrointestinal tissues were markedly lower in cirrhotic rats than in the controls and cirrhotic rats after 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.
