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Voltage‐activated Ca 2+ currents in insulin‐secreting cells
Author(s) -
Findlay Ian,
Dunne Mark J.
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)81040-1
Subject(s) - insulin , chemistry , biophysics , physics , biology , endocrinology
Membrane voltage and voltage‐clamped membrane currents have been investigated with the whole‐cell patch clamp method in the insulin‐secreting cell line RINm5F. The mean resting membrane potential of RINm5F cells was found to be −52 mV. Overshooting spike potentials could be evoked by membrane depolarisation in the absence of a secretagogue. Inward membrane currents evoked by depolarising voltage steps were dependent upon extracellular Ca 2+ and blocked by Co 2+ , nifedipine and verapamil. Outward membrane currents which were evoked by depolarising voltage steps to positive membrane potentials were reduced when Ca 2+ entry was prevented. It is concluded that the voltage‐activated Ca 2+ currents underlie the voltage‐activated spike potentials recorded from insulin‐secreting cells.