Cone inner segments in the salamander retinal slice were voltage-clamped and stimulated with voltage ramps ranging from −150 to 0 mV in the presence of 10 mM external Ca2+.
For whole cell calcium channel current recordings cells were stimulated by voltage steps to +10 mV from a holding potential of −90 mV for 500 ms in a bath solution containing (mM): 140 NaCl, 5.4 CsCl, 10.8 BaCl2, 1 MgCl2, 10 D-Glucose, 10 HEPES, pH 7.3 with CsOH.
Amplitude of the intracellular Ca2+ transient and cell shortening was significantly increased by SEA0400 in both field stimulated and voltage clamped myocytes, without significant elevation of diastolic Ca2+ level and the decay time constant of the Ca2+ transient.
For gap junctional recording, one cell was stimulated by voltage steps and another cell was held at −40 mV to measure the transjunctional currents [14].
The cells were field stimulated with suprathreshold voltage (150% of the threshold voltage of cell contraction) at a frequency of 0.5 Hz, 3 msec duration, using a pair of platinum wires placed on opposite sides of the chamber connected to a FHC stimulator (Brunswick, NE, USA).
In our scenario, three stimulating voltages were defined: the lowest level, the higher level and highest level.
Cells were field stimulated with 2 ms duration voltage pulses delivered through parallel platinum wires (stimulation voltage set to 1.5 times the threshold).
The cells were field stimulated with suprathreshold voltage at a frequency of 0.5 Hz, 3 msec duration, using a pair of platinum wires placed on opposite sides of the chamber and connected to an electrical stimulator (FHC Inc, Brunswick, NE).
The cells were field stimulated with suprathreshold voltage at a frequency of 0.5 Hz, 3 msec duration, using a pair of platinum wires placed on opposite sides of the chamber connected to a FHC stimulator (Brunswick, NE, USA).
