Calcium channel gamma6 subunits are unique modulators of low voltage-activated (Cav3.1) calcium current.

The calcium channel gamma (gamma) subunit family consists of eight members whose functions include modulation of high voltage-activated (HVA) calcium currents in skeletal muscle and neurons, and regulation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propanoic acid (AMPA) receptor targeting. Cardiac myocytes express at least three gamma subunits, gamma(4), gamma(6) and gamma(7), whose function(s) in the heart are unknown. Here we compare the effects of the previously uncharacterized gamma(6) subunit with that of gamma(4) and gamma(7) on a low voltage-activated calcium channel (Cav3.

Disruption of growth hormone secretion alters Ca2+ current density and expression of Ca2+ channel and insulin-like growth factor genes in rat atria.

The influence of the growth hormone (GH)-insulin-like growth factor I (IGF-I) axis on expression of low-voltage-activated (LVA) Ca2+ current in atrial tissue was investigated using spontaneous dwarf (SpDwf) rats, a mutant strain that lacks GH. Atrial myocytes from SpDwf rats express LVA and high-voltage-activated (HVA) Ca2+ currents and the Ca2+ channel alpha1-subunit genes CaV1.2, CaV2.

Distribution and relative expression levels of calcium channel beta subunits within the chambers of the rat heart.

Calcium channel beta subunits expressed in rat atria and atrial myocytes are identified and their expression quantified and compared to beta subunit expression in the ventricle. mRNAs encoding all four know beta subunits are expressed in atrial myocytes including the following splice variants: beta1a, beta2b, beta2c, beta2e and beta4d. The specific beta2 splice variants expressed in the atria (beta2b, beta2c, beta2e) differ from those previously reported from rat ventricle.

Identification of the calcium channel alpha 1E (Ca(v)2.3) isoform expressed in atrial myocytes.

Antisense oligonucleotides targeting the calcium channel alpha 1E (Ca(v)2.3) subunit significantly inhibit the insulin-like growth factor-1 (IGF-1)-stimulated increase in low voltage-activated (LVA) (T-type) calcium current in cultured rat atrial myocytes [Proc. Natl.

Quantitative analysis of the expression and distribution of calcium channel alpha 1 subunit mRNA in the atria and ventricles of the rat heart.

Two distinct calcium currents are present in mammalian cardiac myocytes. Utilizing quantitative RT-PCR methods, we have analysed the expression patterns and abundance of four calcium channel alpha 1 subunit mRNAs in different regions of the rat heart and compared them to the known density of calcium currents recorded from rat atria. Our results show that Ca(V)1.