Endogenous norepinephrine release induced by tyramine modulates intestinal ion transport. Am J Physiol 1981 Sep;241(3):G264-9
Date
09/01/1981Pubmed ID
7282935DOI
10.1152/ajpgi.1981.241.3.G264Scopus ID
2-s2.0-0019614941 (requires institutional sign-in at Scopus site) 30 CitationsAbstract
To study the effects of endogenous norepinephrine on intestinal ion transport, we tested the actions of an indirect sympathomimetic agent, tyramine, on electrolyte fluxes in the short-circuited rabbit ileum in vitro. Tyramine (10(-5) M) alone had no effect on short-circuit current or Na transport but increased Cl absorption. Tyramine decreased the short-circuit current, stimulated both Na and Cl absorption, and increased tissue conductance when its breakdown by endogenous monoamine oxidase enzymes was inhibited by pretreatment with pargyline (10(-4) M). Pargyline alone had no effect on short-circuit current and NaCl transport. The effect of norepinephrine on NaCl transport was inhibited by the alpha-adrenergic receptor antagonist, phentolamine (10(-7) M). This response was also prevented when animals were chemically sympathectomized with 6-hydroxydopamine. Although sympathectomy decreased measurable tissue norepinephrine by 80%, it did not alter basal short-circuit current, Na and Cl absorption, and the short-circuit current response to glucose-stimulated Na transport and to exogenous norepinephrine. Thus, a pool of norepinephrine in intestinal adrenergic neurons released by tyramine affects intestinal ion transport but does not alter basal ion transport. These data suggest close neuropharmacologic similarities between the adrenergic nervous system in the intestine and other organs.
Author List
Tapper EJ, Bloom AS, Lewand DLMESH terms used to index this publication - Major topics in bold
AnimalsChlorides
Electrolytes
Hydroxydopamines
Ileum
Intestinal Absorption
Intestinal Mucosa
Male
Membrane Potentials
Norepinephrine
Pargyline
Phentolamine
Rabbits
Sodium
Sympathectomy, Chemical
Tyramine
