Cukurova Medical Journal

Öz

Purpose:In the present study,
was aimed at investigating the effect of L-cysteine/ hydrogen sulfide (H2S)
pathway on contractile response to potassium chloride in mouse gastric fundus
and possible contributions of nitric oxide (NO) and cyclooxygenase (COX)
pathways in this effect

Material and Methods:The contractile responses to cumulative KCl was
produced in isolated mouse fundus strips and the effect of L-cysteine (10 mM)
on this responses was examined. In addition, the effect of L-cysteine on the
contractile responses to KCI were investigated in the presence cystathionine
beta-synthase (CBS) enzyme inhibitor aminoxyacetic acid (AOAA; 1 mM) and
cystathionine gamma-lyase (CSE) enzyme inhibitor propargyl glycine (PAG, 10 mM),
which mediated the endogenously synthesize of H2S. The possible
contribution of NO and COX pathways to the effect of L-cysteine on KCl
contractions was examined in the presence of L-Nitroarginine (L-NA; 0.1 mM), a
nitric oxide synthase inhibitor and indomethacin (0.001 M), a non-selective COX
inhibitor. 

Results:L-cysteine significantly
attenuated the contractile responses to KCl. The inhibitory effect of
L-cysteine was significantly reversed by AOAA. However, PAG reduced the inhibitory
effect of L-cysteine on the contractile responses to lower concentrations KCl.  In the presence of L-NA, L-cysteine decreased
the maximum contractile response to KCl and this inhibitory effect was reversed
by AOAA and PAG.  The inhibitory effect of
L-cysteine on the contractile response to lower concentration of KCl was
reversed in the presence indomethacin. Indeed, in the presence of L-NA and
indomethacin combination, the inhibitory effect of L-cysteine on the
contractile responses to KCl were reversed by PAG and AOAA pre-incubation

Conclusion:The findings of current study suggest that
L-cystein/H2S pathway has an inhibitory effect on the contractile
response to KCl and this effect may be related NO and COX pathways.