Lansoprazole is widely used nowadays to relieve symptoms
and enhance healing of peptic ulcer and reflux oesophagitis. It
effectively decreases gastric acid secretion, regardless the primary
stimulus, via inhibition of gastric 1-111K+ ATPase (The acid pump).
Lansoprazole action on the gastric parietal cells and acid secretion has
been extensively studied, however, the effect of lansoprazole on GIT
motility and mesenteric haemodynamics remains unclear. The present
study was designed to screen the effects of lansoprazole on GIT
motility in vivo and in vitro. The effect of its acute and chronic
administration on mesenteric blood flow was also determined. To test
whether lansoprazole may alter kidney function as some other proton
pump inhibitors, changes in renal blood flow, urine flow, pH, Na + and
K+ concentrations were also monitored. Our results showed that
increasing doses of lansoprazole induced dose related inhibition of
rhythmic conraction of rabbit's intestine both in-vitro and in-vivo.
Lansoprazole also attenuated ACh induced contraction of rabbit's
intestine, histamine induced contraction of Guinea pig ileum and to
lesser extent serotonin induced contraction of rat fundus strip. The
inhibitory effect of lansoprazole is unlikely to be mediated through
adrenergic or dopaminergic receptors as its action was not affected by
phentolamine, propranolol or metochloprami de. However,
indomethacin was able to attenuate its inhibitory effect indicating the
involvement of prostaglandins in mediating lansoprazole effect.
Lansoprazole produced insignificant changes in the mesenteric blood
flow after both acute and chronic administration. Acute
administratioon of lansoprazole in different doses (0.1, 0.3 and 1
gmol/lcg, IV.) induced dose dependent reduction in renal blood flow.
It reduced urine flow rate, did not change urine pH, urinary Na+ concentration but it increased urinary K concentration. Its chronic
administration (3 urnolikg, IM.) for 4 weeks, caused insignificant
change in renal blood flow, reduced urine flow rate, changed urine pH
towards the alkaline margin, decreased urinary Na' concentration and
increased K' concentration. |
