Intracerebral adrenoceptor agonists influence rat duodenal mucosal bicarbonate secretion

The American Journal of Physiology
G M LarsonG Flemström

Abstract

We have studied the effects of intracerebral administration of selective alpha-adrenergic agonists on duodenal bicarbonate secretion. Duodenum free of Brunner's glands was cannulated in situ in anesthetized rats, and bicarbonate secretion into the luminal reperfusate was continuously titrated by pH stat. Infusion of the alpha 1-selective adrenoceptor agonist, phenylephrine (1,000-2,500 micrograms.kg-1.h-1), into a lateral brain ventricle increased (P < 0.01) duodenal bicarbonate secretion. Pretreatment with prazosin, an alpha 1-antagonist, significantly (P < 0.01) reduced the stimulatory effect when infused into the lateral ventricle (30 micrograms.kg-1.h-1), but not when administered intravenously (1,000 micrograms.kg-1.h-1). Hexamethonium (10 mg.kg-1.h-1 iv) abolished stimulation, whereas cervical vagotomy, epidural blockade, and naloxone were each without effect. Vasopressin, vasopressin antagonists, ts, and oxytocin did not affect basal secretion. Intracerebro-ventricular administration of the alpha 2-adrenoceptor agonist, clonidine (1,000 micrograms.kg-1.h-1), in contrast to alpha 1-receptor activation, decreased (P < 0.01) the secretion. Thus central nervous adrenoceptors influence duodenal mucosal bicarbonate te secretio...Continue Reading

Citations

Mar 29, 2003·Journal of Pineal Research·Markus Sjöblom, Gunnar Flemström
Jun 23, 2007·American Journal of Physiology. Gastrointestinal and Liver Physiology·Magnus W BengtssonGunnar Flemström
Feb 14, 2003·American Journal of Physiology. Gastrointestinal and Liver Physiology·Markus SjöblomGunnar Flemström
Aug 12, 2005·American Journal of Physiology. Gastrointestinal and Liver Physiology·Gunnar Flemström, Markus Sjöblom
Aug 4, 2005·Upsala Journal of Medical Sciences·Markus Sjöblom
Dec 14, 2004·American Journal of Physiology. Cell Physiology·Adrian Allen, Gunnar Flemström

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