Antoine MH, Gall D, Schiffmann SN, Lebrun P. Tricyclic antidepressant imipramine reduces the insulin secretory rate in islet cells of Wistar albino rats through a calcium antagonistic action.
Diabetologia 2004;
47:909-16. [PMID:
15088084 DOI:
10.1007/s00125-004-1384-9]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Accepted: 01/26/2004] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS
Treatments with antidepressants have been associated with modifications in glucose homeostasis. The aim of this study was to assess the effect of imipramine, a tricyclic antidepressant, on insulin-secreting cells.
METHODS
Insulin radioimmunoassay, radioisotopic, fluorimetric and patch-clamp methods were used to characterise the effects of imipramine on ionic and secretory events in pancreatic islet cells from Wistar albino rats.
RESULTS
Imipramine induced a dose-dependent decrease in glucose-stimulated insulin output (IC(50)=5.2 micromol/l). It also provoked a concentration-dependent reduction in (45)Ca outflow from islets perifused in the presence of 16.7 mmol/l glucose. Moreover, imipramine inhibited the increase in (45)Ca outflow mediated by K(+) depolarisation. Patch-clamp recordings further revealed that imipramine provoked a marked and reversible decrease of the inward Ca(2+) current. In single islet cells, imipramine counteracted the rise in [Ca(2+)](i) evoked by glucose or high K(+) concentrations.
CONCLUSIONS/INTERPRETATION
These data indicate that imipramine dose-dependently reduces the insulin secretory rate from rat pancreatic beta cells. Such an effect appears to be mediated by the inhibition of voltage-sensitive Ca(2+) channels with subsequent reduction in Ca(2+) entry. Thus, it is possible that some adverse effects of imipramine are related, at least in part, to its capacity to behave as a Ca(2+) entry blocker.
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