Referenced in: none

Automatically associated channels: Cav1.2 , Cav2.2

Title: Decreased calcium channel currents and facilitated epinephrine release in the Ca2+ channel beta3 subunit-null mice.

Authors: Toshio Ohta, Takayoshi Ohba, Takashi Suzuki, Hiroyuki Watanabe, Hironobu Sasano, Manabu Murakami

Journal, date & volume: Biochem. Biophys. Res. Commun., 2010 Apr 9 , 394, 464-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/20144588

Abstract
The beta subunits of voltage-dependent calcium channels are known to modify calcium channel currents through pore-forming alpha1 subunits. The beta3 subunit is expressed in the adrenal gland and participates in forming various calcium channel types. We performed a series of experiments in beta3-null mice to determine the role of the beta3 subunit in catecholamine release from the adrenal chromaffin system. Protein levels of N-type channel forming CaV2.2 and L-type forming CaV1.2 decreased. The beta3-null mice showed a decreased baroreflex, suggesting decreased sympathetic tonus, whereas plasma catecholamine levels did not change. Pulse-voltage stimulation revealed significantly increased amperometrical currents in beta3-null mice, while patch-clamp recordings showed a significant reduction in Ca(2+)-currents due to reduced L- and N-type currents, indicating facilitated exocytosis. A biochemical analysis revealed increased InsP3 production. In conclusion, our results indicate the importance of the beta3 subunit in determining calcium channel characteristics and catecholamine release in adrenal chromaffin cells.