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Expression of Functional GABA A Receptors in Isolated Human Insulinoma Cells
Author(s) -
GLASSMEIER GÜNTER,
HÖPFNER MICHAEL,
BUHR HEINZ,
LEMMER KARIN,
RIECKEN ERNSTOTTO,
STEIN HARALD,
QUABBE HANSJURGEN,
RANCSO CHRISTOPH,
WIEDENMANN BERTRAM,
SCHERÜBL HANS
Publication year - 1998
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1998.tb11138.x
Subject(s) - gabaa receptor , insulinoma , receptor , endocrinology , medicine , chemistry , paracrine signalling , depolarization , gabaa rho receptor , muscimol , microbiology and biotechnology , stimulation , biology , insulin
Pancreatic islets contain and release high concentrations of GABA. GABA is thought to play a paracrine role in beta-cells. Searching for a paracrine function of GABA in neoplastic beta-cells we performed patch-clamp studies in isolated human insulinoma cells. We show that human insulinoma cells can express functional GABAA receptors. Activation of GABAA receptors caused a reversible membrane depolarization in a subgroup of insulinoma cells. Membrane depolarization resulted in transmembraneous calcium influx through voltage-gated calcium channels and stimulation of insulin secretion. Insulin secretion was increased by the GABAA receptor agonist muscimol (50 microM) by about 280%. Thus, GABAA receptors can be expressed in human insulinoma cells and can regulate their insulin release.