[Electrophysiological study of the action mechanism of somatoliberin (GH-RH) on hypophyseal GH3 tumor cells].
We have investigated the electrical response of patched GH3 cells to Growth-Hormone Releasing-Hormone (GH-RH). GH-RH (100 nM) enhanced firing frequency of action potentials. This is accompanied by membrane depolarization (5-10 mV) and conductance increase. Voltage clamp studies reveal that GH-RH potentiates calcium inward currents and a calcium-dependent chloride current; transient outward current is diminished. These changes in membrane conductance account for the cytosolic free calcium rise shown by Indo-1 fluorescence measurements.
Fahmi
M
M
Laboratoire de Neurophysiologie, CNRS URA 1200, Université de Bordeaux II.
Bresson
L
L
Dufy-Barbe
L
L
Sartor
P
P
Taupignon
A
A
Dufy
B
B
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000502:physiology; D002461:Cell Line, Transformed / Q000502:physiology; D004594:Electrophysiology; D013007:Growth Hormone-Releasing Hormone / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D010911:Pituitary Neoplasms / Q000473:pathology*; D051381:Rats; D014407:Tumor Cells, Cultured
D013007:Growth Hormone-Releasing Hormone; D002118:Calcium
Etude électrophysiologique du mécanisme d'action de la somatolibérine (GH-RH) sur des cellules hypophysaires tumorales GH3.