Molecular and Electrophysiological Differences in the L-Type Ca2+ Channel of the Atrium and Ventricle of Rat Hearts
Year: 2006
Type: article
Abstract: BACKGROUND: Many pathological conditions induce electrical remodeling, possibly through intracellular Ca2+ overload, but the currently available L-type Ca2+ channel blockers may be detrimental because of their global negative inotropic effects. METHODS AND RESULTS: To determine whether the L-type Ca2+ channel is identical throughout the heart, the distribution of the mRNAs and proteins comprising the L-type Ca2+ channel and its electrophysiological properties were analyzed in rat atria and ventricles. The mRNA of alpha2delta-2 (Cacna2d2) was more abundantly expressed in the atrium (approximately 5-fold) than in the ventricle. In contrast, alpha1C (Cacna1c) (Cav1.2) mRNA was significantly less abundant in the atrium. The level of the alpha1C (Cacna1c) (Cav1.2) protein was decreased (approximately 0.5-fold) and that of alpha2 delta-1 (Cacna2d1) was increased (approximately 2-fold) in the atrium compared with the ventricle. Although the peak ICa,L density showed no significant differences, voltage dependence of inactivation and activation of the current showed a more depolarized shift in the atrium than in the ventricle. CONCLUSION: These results indicate that in the rat heart the L-type Ca2+ channel differs between the atrium and ventricle with regard to gene expression and electrophysiological properties.
Source: Circulation Journal
DOI: 10.1253/circj.70.610
Authors: Seiji Hatano, Takeshi Yamashita, Akiko Sekiguchi, Yuki Iwasaki, Kiyoshi Nakazawa, Koichi Sagara, Hiroyuki Iinuma, Tadanori Aizawa, Long-Tai Fu
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2000970024