The release of serotonin from rat duodenal enterochromaffin cells by adrenoceptor agonists studied in vitro

Acta Physiol Scand. 1978 Jun;103(2):219-24. doi: 10.1111/j.1748-1716.1978.tb06209.x.


The serotonin (5-HT) content of enterochromaffin cells (EC) was studied by a cytofluorimetric method in biopsies from rat duodenal mucosa after in vitro incubation with different adrenoceptor agonists and antagonists and acetylcholine (ACh). Noradrenaline (NA), Adrenaline (A) and Isoprenaline (IP) caused a decrease of 5-HT in EC down to 40--60% and for NA and A this effect was concentration-dependent. The effect was antagonized by d,1-propranolol but not by d-propranolol, metoprolol, phentolamine or phenoxybenzamine indicating that the 5-HT release from EC is probably mediated via a true beta-adrenoceptor mechanism possibly of the beta2 type. ACh also decreased the 5-HT content of EC but was much less potent than the adrenergic substances. Dopamine (DA) had no effect.

MeSH terms

  • Acetylcholine / pharmacology
  • Adrenergic beta-Agonists*
  • Adrenergic beta-Antagonists
  • Animals
  • Chromaffin System*
  • Dopamine / pharmacology
  • Duodenum / metabolism
  • Enterochromaffin Cells*
  • Epinephrine / pharmacology
  • Isoproterenol / pharmacology
  • Male
  • Metoprolol / pharmacology
  • Norepinephrine / pharmacology
  • Phenoxybenzamine / pharmacology
  • Phentolamine / pharmacology
  • Propranolol / pharmacology
  • Rats
  • Serotonin / metabolism*


  • Adrenergic beta-Agonists
  • Adrenergic beta-Antagonists
  • Phenoxybenzamine
  • Serotonin
  • Propranolol
  • Metoprolol
  • Isoproterenol
  • Acetylcholine
  • Dopamine
  • Norepinephrine
  • Epinephrine
  • Phentolamine