Ca²⁺ entry through Na_V channels generates submillisecond axonal Ca²⁺ signaling.

ABSTRACT: Calcium ions (Ca²⁺) are essential for many cellular signaling mechanisms and enter the cytosol mostly through voltage-gated calcium channels. Here, using high-speed Ca²⁺ imaging up to 20 kHz in the rat layer five pyramidal neuron axon we found that activity-dependent intracellular calcium concentration ([Ca²⁺]_i) in the axonal initial segment was only partially dependent on voltage-gated calcium channels. Instead, [Ca²⁺]_i changes were sensitive to the specific voltage-gated sodium (Na_V) channel blocker tetrodotoxin. Consistent with the conjecture that Ca²⁺ enters through the Na_V channel pore, the optically resolved I_Ca in the axon initial segment overlapped with the activatio

SUBMITTER: Hanemaaijer NA 

PROVIDER: S-EPMC7380941 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature