Gunnar Flemström

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Secretion of bicarbonate into the adherent layer of mucus gel creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal acid. The continuous adherent mucus layer is also a barrier to luminal pepsin, thereby protecting the underlying mucosa from proteolytic(More)
Orexins are involved in the central nervous control of appetite and behavior, and in addition, they are present in endocrine cells and/or neurons in the intestine. The role of these peptides in peripheral regulation of intestinal secretion has not been investigated. We thus compared the effects of orexin A and some established secretagogues on duodenal(More)
Vagal stimuli increase duodenal mucosal HCO-3 secretion and may provide anticipatory protection against acid injury, but duodenal enterocyte (duodenocyte) responses and cholinoceptor selectivity have not been defined. We therefore developed a stable primary culture model of duodenocytes from rats and humans. Brief digestion of scraped rat duodenal mucosa or(More)
Bicarbonate secretion by duodenum distal to the Brunner's glands area was titrated in situ in rats anesthetized with thiobarbiturate. The unselective muscarinic antagonist atropine (0.4 mg/kg) inhibited secretion stimulated by bethanechol (15 micrograms.kg-1.h-1) but not that stimulated by carbachol (15 micrograms.kg-1.h-1). The nicotinic antagonist(More)
Surface sensory enteroendocrine cells are established mucosal taste cells that monitor luminal contents and provide an important link in transfer of information from gut epithelium to the central nervous system. Recent studies now show that these cells can also mediate efferent signaling from the brain to the gut. Centrally elicited stimulation of vagal and(More)
Presence of appetite-regulating peptides orexin-A and orexin-B in mucosal endocrine cells suggests a role in physiological control of the intestine. Our aim was to characterize orexin-induced stimulation of duodenal bicarbonate secretion and modulation of secretory responses and mucosal orexin receptors by overnight food deprivation. Lewis x Dark Agouti(More)
Close intra-arterial infusion of the appetite regulating peptide orexin-A stimulates bicarbonate secretion from the duodenal mucosa. The aim of the present study was to elucidate the ability of orexin-A to induce intracellular calcium signaling in acutely isolated duodenal enterocytes. Freshly isolated clusters of enterocytes, obtained from rat duodenal(More)
Cholecystokinin (CCK) is an important regulator of food digestion but its influence on small intestinal secretion has received little attention. We characterized effects of CCK-8, ghrelin and some related peptides on duodenal HCO3(-) secretion in vivo and demonstrated CCK-induced calcium signaling in acutely isolated enterocytes. A segment of proximal(More)
Both Necturus and bullfrog antrum show stable PD, resistance, and short-circuit current (Isc) when mounted in an Ussing chamber. Measurements of Na+ and Cl minus flux showed that both ions are actively transported across Necturus antrum, Na+ from secretory to nutrient, Cl minus from nutrient to secretory (both net fluxes being similar to 0.30 mueq cm minus(More)
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