Peripheral mechanism of inhibitory effect of centrally administrated histamine on gastric acid secretion.

AIM:To study the peripheral mechanism of the inhibitory effect of intra-third ventricular administration (icv) of histamine (HA) on gastric acid secretion in rats.METHODS:Gastric acid was continuously washed with 37&mgr; saline by a perfusion pump in male adrenalectomized SD rats. Drugs were injected intravenously (iv) by a syringe pump and their effect on pentagastrin-induced (10&mgr;gcenter dotkgcenter doth, iv) gastric acid secretion was observed.RESULTS:The inhibitory effect of HA (1&mgr;g, icv) on gastric acid secretion was blocked by subdiaphragmatic vagotomy, and pretreatment with atropine (0.005mg-kg-h, iv). Pretreatment with somatostatin antagonist,cyclo- 7-aminoheptanoyl-Phe-D-Trp-Lys-Thr(Bzl) ,(2&mgr;g-4&mgr;g-kg-100min, iv) could also block the inhibitory effect of HA on gastric acid secretion in a dose dependent manner.CONCLUSION:The inhibitory effect of centrally adminis-trated HA on gastric acid secretion may be mediated by vagi, acetylcholine M receptor and somatostatin.