Stimulation of mucosal alkaline secretion in rat duodenum by dopamine and dopaminergic compounds

Gastroenterology. 1993 Mar;104(3):825-33. doi: 10.1016/0016-5085(93)91019-e.


Background: The catechol-O-methyl-transferase (COMT) inhibitor nitecapone, which prevents mucosal degradation of dopamine, and some dopamine receptor agonists ameliorate gastroduodenal mucosal damage. Therefore, their effects on mucosal bicarbonate secretion were studied.

Methods: Duodenum just distal to the Brunner's glands area was cannulated in situ in anesthetized rats. Bicarbonate secretion into the luminal perfusate and transmucosal electrical potential difference (PD) were recorded.

Results: Intravenous dopamine (50 x h-1) increased bicarbonate secretion twofold, and a higher rate of infusion (250 x h-1) resulted in a further increase. Neither dose affected the PD. The dopamine D1 agonist SKF-38393 (10-50 micrograms/kg) and the COMT inhibitor nitecapone (50-500 micrograms/kg) caused dose-dependent increases in secretion, similar to that observed with dopamine. Domperidone, a peripherally acting dopamine antagonist, inhibited the stimulatory effects of SKF-38393 and nitecapone. Hexamethonium or the alpha-adrenoceptor antagonist phentolamine, in contrast, did not affect the response to nitecapone. Intracerebroventricular administration of nitecapone was without effect.

Conclusions: A probable electroneutral component of duodenal mucosal bicarbonate secretion is stimulated via peripheral dopamine D1 receptors. This may contribute to the previously observed ulceroprotective actions of dopaminergic compounds.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / pharmacology
  • Animals
  • Bicarbonates / metabolism*
  • Blood Pressure / drug effects
  • Catechol O-Methyltransferase Inhibitors*
  • Catechols / pharmacology*
  • Dopamine / pharmacology*
  • Dopamine Agents / pharmacology*
  • Duodenal Ulcer / prevention & control
  • Duodenum / drug effects*
  • Duodenum / metabolism
  • Hexamethonium
  • Hexamethonium Compounds / pharmacology
  • Intestinal Mucosa / drug effects*
  • Intestinal Mucosa / metabolism
  • Male
  • Pentanones / pharmacology*
  • Phentolamine / pharmacology
  • Rats
  • Rats, Sprague-Dawley


  • Bicarbonates
  • Catechol O-Methyltransferase Inhibitors
  • Catechols
  • Dopamine Agents
  • Hexamethonium Compounds
  • Pentanones
  • Hexamethonium
  • 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine
  • nitecapone
  • Dopamine
  • Phentolamine