Two Types of Voltage-activated Calcium Currents in Goldfish Horizontal Cells
The Korean Journal of Physiology and Pharmacology
;
: 269-273, 2005.
Article
in English
| WPRIM
| ID: wpr-728720
ABSTRACT
In horizontal cells (HCs) that were freshly dissociated from goldfish retina, two types of voltage- dependent calcium currents (ICa) were recorded using a patch-clamping configuration a transient type current and a sustained type current. The cell was held at -40 mV, and the prepulse step of -90 mV was applied before command pulse between -65 and +55 mV. The transient Ca2+ current was activated by depolarization to around -50 mV from a prepulse voltage of -90 mV lasting at least 400 ms and reached a maximal value near -25 mV. On the other hand, the sustained Ca2+ current was induced by pre-inactivation for less than 10 ms duration. Its activation started near -10 mV and peaked at +20 mV. Co2+ (2 mM) suppressed both of these two components, but nifedipine (20microM), L-type Ca2+ channel antagonist, blocked only the sustained current. Based on the activation voltage and the pharmacological specificity, the sustained current appears to be similar to L-type ICa and the transient type to T-type ICa. This study is the first to confirm that transient type ICa together with the sustained one is present in HCs dissociated from goldfish retina.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Retina
/
Goldfish
/
Nifedipine
/
Calcium
/
Sensitivity and Specificity
/
Hand
Type of study:
Diagnostic study
Language:
English
Journal:
The Korean Journal of Physiology and Pharmacology
Year:
2005
Type:
Article
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