Effects of Fluoxetine on Membrane Potential and Ionic Currents in RINm5F Insulinoma Cells / 대한정신약물학회지
Korean Journal of Psychopharmacology
;
: 233-241, 2001.
Article
in Korean
| WPRIM
| ID: wpr-153167
ABSTRACT
OBJECTIVE:
The purpose of this study was to investigate the effects of fluoxetine (Prozac) on membrane potential and ionic currents in RINm5F insulinoma cells.METHODS:
Membrane potential and ionic currents in RINm5F cell were recorded by using whole-cell and perforated-patch clamp techniques.RESULTS:
Under current clamp conditions, diazoxide (200 microM), an activator of K ATP channels, induced a hyperpolarization of the resting membrane potential (-16.1+/-1.4 mV, n=), which was accompanied by a abolition of action potential firing. This diazoxide-induced hyperpolarization was blocked by glibenclamide (10 microM). Fluoxetine produced significant depolarization of membrane potential (15.9+/-3.1 mV, n=) and blocked diazoxide-induced hyperpolarization. Diazoxide activated inward currents in the presence of high external K + (90 mM) at a holding potential of -60 mV. Fluoxetine suppressed diazoxide-activated currents in a concentration-dependent (IC 50 =.84 microM) manner. However, the inhibitory action of fluoxetine was not specific to K ATP currents because it also inhibited both voltage-activated K + and Ca 2+ currents in a concentration-dependent manner. K ATP currents were more sensitive to fluoxetine block than both voltage-activated K + and Ca 2+ currents.CONCLUSION:
Our results indicate that fluoxetine increased excitability of RINm5F cells mainly by the preferential block of K ATP currents. Fluoxetine-induced depolarization may influence insulin secretion in insulinoma cells.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Action Potentials
/
Adenosine Triphosphate
/
Fluoxetine
/
Glyburide
/
Diazoxide
/
Fires
/
Insulin
/
Insulinoma
/
Membrane Potentials
/
Membranes
Language:
Korean
Journal:
Korean Journal of Psychopharmacology
Year:
2001
Type:
Article
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