Regulation of neurotensin release from canine enteric primary cell cultures
Barber, D.L.; Buchan, A.M.; Walsh, J.H.; Soll, A.H.
American Journal of Physiology 250(3 Pt 1): G385-G390
1986
ISSN/ISBN: 0002-9513 PMID: 2869696 Document Number: 283142
A recently developed primary cell-culture system allows direct study of the cellular mechanisms regulating neurotensin secretion from intestinal mucosal cells. We now report the use of these methods to evaluate the modulation of neurotensin release by adrenergic, cholinergic, and peptidergic transmitters. Collagenase-dispersed canine ideal mucosal cells, enriched for neurotensin-like immunoreactivity (NTLI) by centrifugal elutriation, were maintained for 48 h on collagen-coated culture dishes. Epinephrine (0.01-100 .mu.M) stimulated a dose-dependent increase in NTLI release. Isoproterenol (10 .mu.M) produced a similar increase in NTLI secretion. The NTLI response to epinephrine was competitively inhibited by propranolol, producing a parallel rightward shift of the epinephrine dose-respnse curve. .alpha.-Adrenergic agonists methoxamine (10 .mu.M) and chlnidine (10 .mu.M) did not alter basal NTLI secretion. Epinephrine stimulation was not significantly inhibited by the .alpha.-adrenergic antagonists prazosin (10 .mu.M) or yohimbine (10 .mu.M). The diterpene forskolin, an adenyl cyclase activator, increased NTLI release and had an additive effect on the response to epinephrine. In contrast to .beta.-adrenergic activation, carbachol and somatostatin produced a dose-dependent inhibition of epinephrine-stimulation NTLI release. At 100 .mu.M carbachol, NTLI rlease was inhibited 68%, and this action was partially blocked by atropine (0.1 .mu.M). Somatostatin (100 nM) produced a 96% inhibition that was not surmountable by 1 mM epinephrine. These data indicate that neurotensin release is stimulated by the .beta.-adrenergic agonists and adenylate cyclase activation. Somatostatin and the muscarinic agonist carbachol directly inhibit NTLI release.