Amiloride selectively blocks the low threshold (T) calcium channel.

Area of Science:

• Neuroscience
• Pharmacology
• Cell Biology

Background:

• Multiple types of voltage-gated calcium channels exist in neurons and muscle cells.
• Specific blockers for high-threshold (L-type) calcium channels are known.
• Selective blockers for low-threshold (T-type) calcium channels were previously unidentified.

Purpose of the Study:

• To identify a selective blocker for the low-threshold (T-type) calcium channel.
• To investigate the potential of amiloride as a T-type calcium channel blocker.

Main Methods:

• Electrophysiological studies on mouse neuroblastoma cells.
• Electrophysiological studies on chick dorsal root ganglion neurons.
• Assessment of amiloride's effect on calcium channel activity.

Main Results:

• Amiloride demonstrated selective blockade of the low-threshold (T-type) calcium channel.
• This selective blockade was observed in both neuroblastoma and dorsal root ganglion neurons.

Conclusions:

• Amiloride is a novel, selective blocker of the T-type calcium channel.
• This finding facilitates the identification and physiological characterization of T-type calcium channels in various tissues.