Lower density of L-type and higher density of P/Q-type of calcium channels in chromaffin cells of hypertensive, compared with normotensive rats

Lower density of L-type and higher density of P/Q-type of calcium channels in chromaffin cells of hypertensive, compared with normotensive rats

Author Pascual, Ricardo de Google Scholar
Miranda-Ferreira, Regiane Autor UNIFESP Google Scholar
Galvao, Kleber M. Autor UNIFESP Google Scholar
Lameu, Claudina Google Scholar
Ulrich, Henning Google Scholar
Smaili, Soraya Soubhi Autor UNIFESP Google Scholar
Jurkiewicz, Aron Autor UNIFESP Google Scholar
Garcia, Antonio G. Google Scholar
Gandia, Luis Google Scholar
Institution Univ Autonoma Madrid
Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract Enhanced activity of the sympatho-adrenal axis and augmented circulating catecholamines has been implicated in the development of hypertension. Release of catecholamine from stimulated adrenal medulla chromaffin cells has been shown to be higher and longer in spontaneously hypertensive rats (SHRs), compared with normotensive Wistar rats (NWRs). Whether differences in the functional expression of voltage-dependent calcium channels (VDCCs) of the L-, N-, or P/Q subtypes may contribute to such distinct secretory behaviour, is unknown. We therefore approached here this study in voltage-clamped NWR and SHR chromaffin cells, using 10 mM Ba2+ as charge carrier (I-Ba) and selective blockers of each channel type. We found that compared with NWR cells, SHR chromaffin cells exhibited the following differences: (1) 30% diminution of the I-Ba fraction carried by L channels; (2) a doubling of the I-Ba fraction carried by P/Q channels; (3) more visible current modulation by ATP that could be linked to a 10-fold higher mRNA levels for purinergic receptors of the P-2Y2 subtype; and (3) a higher contribution of PQ channels to the transients of the cytosolic calcium concentrations ([Ca2+](c)) generated by K+, compared with L channels. These results may contribute to the better understanding of the greater calcium signalling and exocytotic responses of SHR compared with NWR chromaffin cells, found in three previous reports from our laboratories. (C) 2013 Elsevier B.V. All rights reserved.
Keywords Spontaneously hypertensive rats (SHR)
Chromaffin cells
Catecholamine release
Cytosolic calcium
Calcium channels
Language English
Sponsor Government of Spain
Government of Brazil
Ministerio de Economia y Competitividad, Spain
RETICS, Instituto de Salud Carlos III
Ministerio de Economia y Competitividad
Grant number Government of Spain: PHB2011-0029-PC
Government of Spain: PHB2011-0031-PC
Government of Brazil: PHB2011-0029-PC
Government of Brazil: PHB2011-0031-PC
Ministerio de Economia y Competitividad, Spain: SAF2010-18837
RETICS, Instituto de Salud Carlos III: RD 06/0026
Ministerio de Economia y Competitividad: SAF2010-21795
Date 2013-04-15
Published in European Journal of Pharmacology. Amsterdam: Elsevier B.V., v. 706, n. 1-3, p. 25-35, 2013.
ISSN 0014-2999 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 25-35
Origin http://dx.doi.org/10.1016/j.ejphar.2013.02.046
Access rights Closed access
Type Article
Web of Science ID WOS:000317747700005
URI http://repositorio.unifesp.br/handle/11600/36210

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