EXTRAHEPATIC PORTAL HYPERTENSIVE GASTROPATHY IN WISTAR RATS - MODULATION OF ACID-SECRETION IN ISOLATED PARIETAL-CELLS

Stimulated acid secretion in portal hypertensive gastropathy is blunte d and could be due to defective signal transduction in the parietal ce ll. Therefore, an attempt was made to study the levels of second messe ngers in parietal cells in experimental extrahepatic portal hypertensi ve gastropathy. Our aim was to measure acid secretion, intracellular f ree calcium, calcium transport, cyclic AMP, and ATP levels in the pari etal cells isolated from the gastric mucosa of portal hypertensive rat s. Acid secretion using acridine orange, intracellular free calcium us ing Fura-2/AM, calcium influx and efflux by (CaCl2)-Ca-45 and cyclic A MP by RIA kits were measured in unstimulated and histamine-and carbach ol-stimulated isolated parietal cells in rats with partial portal vein ligation and sham operation. ATP was measured by HPLC. In portal hype rtensive gastropathy, stimulated acid secretion was blunted, and there was a decrease in basal intracellular free calcium. Calcium influx an d efflux were at a higher level, and there was a decrease in elevation of intracellular free calcium and cyclic AMP levels with secretagogue s. There was also a decrease in ATP. In conclusion, there exists a low energy state in addition to multiple aberrations at the second messen ger level in parietal cells in portal hypertensive gastropathy.