Antisense depletion of beta-subunits modulates the biophysical and pharmacological properties of neuronal calcium channels.
J Physiol
; 482 ( Pt 3): 481-91, 1995 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-7537818
ABSTRACT
1. The role of the voltage-dependent calcium channel (VDCC) beta-subunit has been examined in cultured rat dorsal root ganglion neurones (DRGs). An antipeptide antibody was raised and this recognized proteins corresponding to beta-subunits in a number of preparations. Immunoreactivity for the VDCC beta-subunit in DRGs was concentrated on the internal side of the plasma membrane but was also present in the cytoplasm. 2. A twenty-six-mer antisense oligonucleotide with homology to all published VDCC beta-subunit sequences was microinjected into individual cells, and maximal depletion of VDCC beta-subunit immunoreactivity was observed after 108 h suggesting a half-life for the turnover of the beta-subunit greater than 50 h. No depletion was obtained with nonsense oligonucleotide. 3. The effect of depletion of VDCC beta-subunit immunoreactivity on calcium channel currents in these cells was a reduction in amplitude of the maximum current of about 47%, and a shift in the voltage dependence of current activation of about +7 mV. These effects are the converse of those observed following co-expression of cloned beta- with alpha 1-subunits in oocytes and other expression systems. 4. The ability of the 1,4-dihydropyridine (DHP) agonist Bay K 8644 to enhance calcium channel currents was greatly reduced following depletion of beta-subunit immunoreactivity. This result is in agreement with the finding in several systems that co-expression of the beta-subunit with alpha 1-subunits results in an increased number of DHP binding sites. 5. These results show that calcium channel beta-subunits form part of native neuronal calcium channels and modify their biophysical and pharmacological properties.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Canais de Cálcio
/
Oligonucleotídeos Antissenso
/
Neurônios
Limite:
Animals
Idioma:
En
Ano de publicação:
1995
Tipo de documento:
Article