Different contributions of calcium channel subtypes to electrical excitability of chromaffin cells in rat adrenal slices

作者：Albinana Elisa; Segura Chama Pedro; Baraibar Andres M; Hernandez Cruz Arturo; Hernandez Guijo Jesus M^*

来源：Journal of Neurochemistry, 2015, 133(4): 511-521.

DOI：10.1111/jnc.13055

• action potentials
• adrenal slices
• calcium channels
• rat chromaffin cell

We characterized the ionic currents underlying the cellular excitability and the Ca2+-channel subtypes involved in action potential (AP) firing of rat adrenal chromaffin cells (RCCs) preserved in their natural environment, the adrenal gland slices, through the perforated patch-clamp recording technique. RCCs prepared from adrenal slices exhibit a resting potential of -54 mV, firing spontaneous APs (2-3 spikes/s) generated by the opening of Na+ and Ca2+-channels, and terminated by the activation of voltage and Ca2+-activated K+-channels (BK). Ca2+ influx via L-type Ca2+-channels is involved in reaching threshold potential for AP firing, and is responsible for activation of BK-channels contributing to A-Prepolarization and afterhyperpolarization, whereas P/Q-type Ca2+-channels are involved only in the repolarization phase. BK-channels carry total outward current during AP-repolarization. Blockade of L-type Ca2+-channels reduces BK-current similar to 60%, whereas blockade of N- or P/Q-type produces little effect. This study demonstrates that Ca2+ influx through L-type Ca2+-channels plays a key role in modulating the threshold potential from RCCs in situ.

• 出版日期2015-5