neuropeptide-y and Stomach-Ulcer

We investigated the central effects of neuropeptide Y (NPY) on stress-induced gastric ulcers in water immersion rats. Intracisternally administered NPY dose-dependently aggravated, but intravenously administered NPY did not affect stress ulcers in rats. Intraperitoneal pre-treatment of atropine completely blocked the central effect of NPY, but neither pyrilamine nor cimetidine affected. Intracisternal administration of NPY aggravated stress ulcers not through histamine mediated mechanism but by parasympathetic pathway. It is suggested that centrally administered NPY acted by the inhibition on gastric motility and by the suppression on gastric mucosal blood flow rather than by the stimulation on gastric secretion in rats.

Topics: Animals; Male; Neuropeptide Y; Parasympathetic Nervous System; Rats; Rats, Wistar; Stomach Ulcer; Stress, Physiological; Thyrotropin-Releasing Hormone

The present study examined the effects of neuropeptide Y (NPY) and a selective NPY1 receptor agonist, leucine31 proline34 neuropeptide Y ([leu31,pro34]NPY) on gastric lesion formation and gastric secretion in three preparations: Basal gastric acid secretion in conscious rats, restraint-induced gastric lesion formation and acid and pepsin output and gastric mucosal damage in pylorus-ligated rats. The hypothesis that benextramine, a non-selective NPY receptor antagonist, could attenuate responses to NPY or [leu31,pro34]NPY was also tested. Both NPY and [leu31,pro34]NPY (i.p. and i.c.v.) decreased basal gastric acid output, restraint-induced gastric lesion formation, and acid and pepsin secretion and gastric mucosal damage in pylorus-ligated rats. The magnitude of inhibition of secretion and of ulcer reduction was significantly greater for [leu31,pro34]NPY than for NPY at comparable doses. Benextramine blocked the protective effect of NPY and [leu31,pro34]NPY against restraint-induced gastric mucosal injury. Both central and peripheral treatment with benextramine blocked the antisecretory effects of centrally administered NPY and [leu31,pro34]NPY. These data were consistent with both a central and a peripheral action of NPY on the gut, possibly through Y1 receptors.

Topics: Adrenergic alpha-Antagonists; Animals; Cystamine; Gastric Acid; Gastric Mucosa; Immobilization; Ligation; Male; Neuropeptide Y; Pepsin A; Pylorus; Rats; Rats, Sprague-Dawley; Receptors, Neuropeptide Y; Stomach; Stomach Ulcer; Stress, Physiological

1. The effects of neuropeptide Y (NPY) and noradrenaline on rat gastric mucosal blood flow, as estimated by laser Doppler flowmetry (LDF), have been examined. In addition, the ability of NPY and noradrenaline to induce acute mucosal haemorrhagic damage has also been assessed. 2. Close-arterial infusion of NPY (0.05-0.2 nmol kg-1 min-1) for 10 min in the anaesthetized rat induced a dose-dependent fall in LDF, but had minimal effects on systemic arterial blood pressure. Higher doses of NPY did not produce any further reduction in LDF. 3. Close-arterial infusion (0.1-0.4 nmol kg-1 min-1) of the structurally related peptide YY (PYY) or pancreatic polypeptide (PP), had inconsistent actions in decreasing LDF. 4. Close-arterial infusion of noradrenaline (30-90 nmol kg-1 min-1) dose-dependently reduced gastric LDF. 5. Local infusion of NPY (0.1 and 0.2 nmol kg-1 min-1) or noradrenaline (45 and 60 nmol kg-1 min-1) resulted in dose-related increases in the area of mucosal hemorrhagic damage. 6. Pretreatment with the alpha 1-adrenoceptor antagonist, prazosin (0.1 mg kg-1, i.v.) significantly reduced the effect of noradrenaline, but not NPY, on both LDF and mucosal damage. 7. These findings indicate that NPY and noradrenaline act directly on the gastric microvasculature to induce vasoconstriction and both can induce acute mucosal damage. Therefore endogenous NPY, like noradrenaline could play a modulatory role in regulating vascular tone and may influence mucosal integrity.

Topics: Anesthesia; Animals; Blood Pressure; Dose-Response Relationship, Drug; Gastric Mucosa; Gastrointestinal Hemorrhage; In Vitro Techniques; Male; Neuropeptide Y; Norepinephrine; Pancreatic Polypeptide; Prazosin; Rats; Rats, Inbred Strains; Regional Blood Flow; Stomach Ulcer

The effects of intracerebroventricular administration of neuropeptide Y (NPY) on stress-induced gastric erosion in the rat were investigated. Animals were exposed to water immersion stress after a single injection of 2 nmol NPY. Stress-induced erosion was reduced by approximately 50%. The plasma corticosterone levels were not affected. We interpret the protective effect of NPY as a manifestation of its sedative properties.

Topics: Animals; Corticosterone; Injections, Intraventricular; Male; Neuropeptide Y; Rats; Rats, Inbred Strains; Stomach Ulcer; Stress, Physiological