SEROTONIN AND NITRIC OXIDE IN INJURY AND HEALING OF

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Just found this interesting study in rats. Elevated serotonin is often an issue

in autism...

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SEROTONIN AND NITRIC OXIDE IN INJURY AND HEALING OF

GASTRIC MUCOSA

Drobinska O.V., Ostapchenko L., Tsyryuk O.I., Ovcharik T.V.

Kyiv National Shevchenko University, Ukraine

e-mail: biochem@...

The aim of the presented work was to study the influence of nitric oxide (NO)

on damages in gastric mucosa (GM) evoked by serotonin.

Male white rats weighting 180-200 g were used. These animals were starved for

24 h prior to experiments, but were allowed free access to water. Gastric injury

was induced in rats by i.p. injection of serotonin creatinine sulfate complex

(10

mg/kg) (Sigma Chemical). We investigated the influence of NO donor sodium

nitroprusside (SNP) (Sigma Chemical) on gastric injury induced by serotonine.

Since injected serotonin is completely metabolized by monoaminooxidase in

about 100-120 minutes, two hours later the animals were killed and their

stomachs were removed. We evaluated the length of erosions, area of ulcers and

massive hemorrhages. Simultaneously the content of NO2

- in the blood was

estimated with Griess reactive. Products of painting were spectrophotometrised

on waves of ?=540-550 nm. Results of spectrophotometry were sorted and

medium data were counted and taken to estimate the concentration of NO2

- by

calibration curve. NO synthase (NOS) activity was measured in homogenate of

GM by method described by Hevel et al. (1991).

Serotonin evoked the formation in GM of erosions (5,18+0,95 mm), ulcers

(8,48+3,10 mm2) and hemorrhages (3,68+1,02 mm2). Serotonin enhanced the

NOS activity by 43% (p<0,05). In results the content of NO2

- in the blood was

increased by 23% (p<0,05). SNP in doses 1-4 mg/kg markedly protected the rat

GM from damages induced by serotonin. SNP had dose-dependent action.

We concluded that in reply to vasoconstriction in GM evoked by serotonin

occurs compensatory the generation of NO (vasodilating agent) via the action of

the NOS. However this level of NO isn't insufficient to protection of GM from

damages. That's why treatment of NO donor SNP protected GM from injury

induced by serotonine.