| Novokinin is a novel synthetic hexapeptide which is modified from ovokinin, an anti-hypertensive bio-active peptide. The previous results showed that novokinin could significantly reduce the blood pressure of spontaneous hypertensive rats (SHRs), and this effect was100times more potent than that of ovokinin (2-7). The results have provided another potential way to develop a new drug to cure the hypertension. However, little is known about other functions of this peptide, especially on the gastrointestinal system.Effects of novokinin on gastric acid secretion and acute gastric mucosal lesion were investigated in rats. Intracerebroventricular administration of novokinin (50and100nmol) significantly decreased basal gastric acid output in a dose-related manner. Vagotomy did not completely abolish the inhibitory effect of novokinin on pentagastrin-stimulated gastric acid secretion. However, the effect of novokinin on gastric acid secretion was reversed by centrally injection of PD123319(10nmol/rat), an AT2receptor antagonist, and peripheral injection of indomethacin (10mg/kg), an inhibitor of prostaglandin synthesis, as well as L798106, a specific EP3receptor antagonist. These findings suggested the inhibitory effect of novokinin on gastric acid secretion might be mediated via AT2and EP3receptors, and vagus nerve might be involved in. Intravenous injection of novokinin (0.06-0.24mg/kg) reduced the acute gastric mucosal lesion induced by ethanol dose-relatedly. |
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