• Elisa Albiñana, Pedro Segura-Chama, Andres M Baraibar, Arturo Hernández-Cruz, and Jesus M Hernández-Guijo.
• Departament of Pharmacology and Therapeutics, University Autónoma de Madrid, Madrid, Spain; Instituto Teófilo Hernando, University Autónoma de Madrid, Madrid, Spain; Facultad de Medicina, University Autónoma de Madrid, Madrid, Spain.
• J. Neurochem. 2015 May 1; 133 (4): 511-21.

AbstractWe characterized the ionic currents underlying the cellular excitability and the Ca(2+) -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 Ca(2+) -channels, and terminated by the activation of voltage and Ca(2+) -activated K(+) -channels (BK). Ca(2+) influx via L-type Ca(2+) -channels is involved in reaching threshold potential for AP firing, and is responsible for activation of BK-channels contributing to AP-repolarization and afterhyperpolarization, whereas P/Q-type Ca(2+) -channels are involved only in the repolarization phase. BK-channels carry total outward current during AP-repolarization. Blockade of L-type Ca(2+) -channels reduces BK-current ~60%, whereas blockade of N- or P/Q-type produces little effect. This study demonstrates that Ca(2+) influx through L-type Ca(2+) -channels plays a key role in modulating the threshold potential from RCCs in situ. This study demonstrates that Ca(2+) influx through L-type Ca(2+) channels plays a key role in modulating the threshold potential for action potential firing and activating BK channels contributing to repolarization and afterhyperpolarization from rat adrenal chromaffin cells in situ.© 2015 International Society for Neurochemistry.

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