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Fraction of the whole cell Ca2+ current carried by P/Q channel (P-type calcium channel ("Purkinje") /Q-type calcium channel) in chromaffin cells

Range	bovine 50%: human 60%: pig & cat 5%: rat 20%: mouse (early study) ~30% (more recent study) 15% % of the whole cell Ca2+ current
Organism	Mammals
Reference	García AG et al., Calcium signaling and exocytosis in adrenal chromaffin cells. Physiol Rev. 2006 Oct86(4):1093-131. DOI: 10.1152/physrev.00039.2005 p.1098 right column 3rd paragraphPubMed ID17015485
Primary Source	[5] Albillos A et al., Calcium channel subtypes in cat chromaffin cells. J Physiol 477: 197–213, 1994. [10] Albillos A, Garcia AG, Olivera B, and Gandia L. Re-evaluation of the P/Q Ca2+ channel components of Ba2+ currents in bovine chromaffin cells superfused with solutions containing low and high Ba2+ concentrations. Pflügers Arch 432: 1030–1038, 1996. [12] Aldea M et al., A perforated patch-clamp study of calcium currents and exocytosis in chromaffin cells of wild-type and alpha(1A) knockout mice. J Neurochem 81: 911–921, 2002. [158] Gandia L, Borges R, Albillos A, and Garcia AG. Multiple calcium channel subtypes in isolated rat chromaffin cells. Pflügers Arch 430: 55–63, 1995. [162] Gandía L et al. Human adrenal chromaffin cell calcium channels: drastic current facilitation in cell clusters, but not in isolated cells. Pflugers Arch. 1998 Oct436(5):696-704. DOI: 10.1007/s004240050691 [191] Hernandez-Guijo JM, de Pascual R, Garcia AG, and Gandia L. Separation of calcium channel current components in mouse chromaffin cells superfused with low- and high-barium solutions. Pflügers Arch 436: 75–82, 1998. DOI: 10.1007/s004240050606 [226] Kitamura N, Ohta T, Ito S, and Nakazato Y. Calcium channel subtypes in porcine adrenal chromaffin cells. Pflügers Arch 434: 179–187, 1997. DOI: 10.1007/s004240050381PubMed ID7523660, 8781197, 12065603, 7545281, 9716702, 9560449, 9136672
Comments	P.1098 right column 3rd paragraph: "The fraction of current carried by P/Q channels in bovine chromaffin cells amounts to 50% (primary source 10). This fraction is even higher (60%) in human chromaffin cells (primary source 162). The opposite occurs in pig (primary source 226) and cat chromaffin cells (primary source 5) where P/Q channels carry only 5% of the current. Finally, in rat chromaffin cells, P/Q channels contribute 20% to the current (primary source 158) and ∼30% in mouse chromaffin cells in the earlier study (primary source 191), but more recent studies report that P/Q channels make only 15% of the current in the mouse cells (primary source 12)."
Entered by	Uri M
ID	113140