Modified sympathetic nerve system activity with overexpression of the voltage-dependent calcium channel beta3 subunit

N-type voltage-dependent calcium channels (VDCCs) play determining roles in calcium entry at sympathetic nerve terminals and trigger the release of the neurotransmitter norepinephrine. The accessory beta3 subunit of these channels preferentially forms N-type channels with a pore-forming CaV2.2 subunit. To examine its role in sympathetic nerve regulation, we established a beta3-overexpressing transgenic (beta3-Tg) mouse line. In these mice, we analyzed cardiovascular functions such as electrocardiography, blood pressure, echocardiography, and isovolumic contraction of the left ventricle with a Langendorff apparatus. Furthermore, we compared the cardiac function with that of beta3-null and CaV2.2 (alpha1B)-null mice. The beta3-Tg mice showed increased expression of the beta3 subunit, resulting in increased amounts of CaV2.2 in supracervical ganglion (SCG) neurons. The beta3-Tg mice had increased heart rate and enhanced sensitivity to N-type channel-specific blockers in electrocardiography, blood pressure, and echocardiography. In contrast, cardiac atria of the beta3-Tg mice revealed normal contractility to isoproterenol. Furthermore, their cardiac myocytes showed normal calcium channel currents, indicating unchanged calcium influx through VDCCs. Langendorff heart perfusion analysis revealed enhanced sensitivity to electric field stimulation in the beta3-Tg mice, whereas beta3-null and Cav2.2-null showed decreased responsiveness. The plasma epinephrine and norepinephrine levels in the beta3-Tg mice were significantly increased in the basal state, indicating enhanced sympathetic tone. Electrophysiological analysis in SCG neurons of beta3-Tg mice revealed increased calcium channel currents, especially N- and L-type currents. These results identify a determining role for the beta3 subunit in the N-type channel population in SCG and a major role in sympathetic nerve regulation.

Medienart:

E-Artikel

Erscheinungsjahr:

2008

Erschienen:

2008

Enthalten in:

Zur Gesamtaufnahme - volume:283

Enthalten in:

The Journal of biological chemistry - 283(2008), 36 vom: 05. Sept., Seite 24554-60

Sprache:

Englisch

Beteiligte Personen:

Murakami, Manabu [VerfasserIn]
Ohba, Takayoshi [VerfasserIn]
Xu, Feng [VerfasserIn]
Satoh, Eisaku [VerfasserIn]
Miyoshi, Ichiro [VerfasserIn]
Suzuki, Takashi [VerfasserIn]
Takahashi, Yoichirou [VerfasserIn]
Takahashi, Eiki [VerfasserIn]
Watanabe, Hiroyuki [VerfasserIn]
Ono, Kyoichi [VerfasserIn]
Sasano, Hironobu [VerfasserIn]
Kasai, Noriyuki [VerfasserIn]
Ito, Hiroshi [VerfasserIn]
Iijima, Toshihiko [VerfasserIn]

Links:

Volltext

Themen:

Cacna1b protein, mouse
Cacnb3 protein, mouse
Calcium
Calcium Channels
Calcium Channels, N-Type
Journal Article
Norepinephrine
Research Support, Non-U.S. Gov't
SY7Q814VUP
X4W3ENH1CV

Anmerkungen:

Date Completed 20.10.2008

Date Revised 20.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1074/jbc.M802319200

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM180913441