Characterization of noradrenaline-induced increases in intracellular Ca2+ levels in Chinese hamster ovary cells stably expressing human alpha1A-adrenoceptor

J Pharmacol Sci. 2007 Sep;105(1):103-11. doi: 10.1254/jphs.fp0070891. Epub 2007 Sep 8.

Abstract

The mechanism for noradrenaline (NA)-induced increases in intracellular Ca(2+) concentration ([Ca(2+)](i)) and physiological significance of Na(+) influx through receptor-operated channels (ROCs) and store-operated channels (SOCs) were studied in Chinese hamster ovary (CHO) cells stably expressing human alpha(1A)-adrenoceptor (alpha(1A)-AR). [Ca(2+)](i) was measured using the Ca(2+) indicator fura-2. NA (1 microM) elicited transient and subsequent sustained [Ca(2+)](i) increases, which were inhibited by YM-254890 (G(alphaq/11) inhibitor), U-73122 (phospholipase C (PLC) inhibitor), and bisindolylmaleimide I (protein kinase C (PKC) inhibitor), suggesting their dependence on G(alphaq/11)/PLC/PKC. Both phases were suppressed by extracellular Ca(2+) removal, SK&F 96365 (inhibitor of SOC and nonselective cation channel type-2 (NSCC-2)), LOE 908 (inhibitor of NSCC-1 and NSCC-2), and La(3+) (inhibitor of transient receptor potential canonical (TRPC) channel). Reduction of extracellular Na(+) and pretreatment with KB-R7943, a Na(+)/Ca(2+) exchanger (NCX) inhibitor, inhibited both phases of [Ca(2+)](i) increases. These results suggest that 1) stimulation of alpha(1A)-AR with NA elicits the transient and sustained increases in [Ca(2+)](i) mediated through NSCC-2 that belongs to a TRPC family; 2) Na(+) influx through these channels drives NCX in the reverse mode, causing Ca(2+) influx in exchange for Na(+) efflux; and 3) the G(alphaq/11)/PLC/PKC-dependent pathway plays an important role in the increases in [Ca(2+)](i).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetamides / pharmacology
  • Animals
  • CHO Cells
  • Calcium / metabolism*
  • Calcium Channels, L-Type / metabolism
  • Cricetinae
  • Cricetulus
  • Dose-Response Relationship, Drug
  • Estrenes / pharmacology
  • GTP-Binding Protein alpha Subunits, Gq-G11 / metabolism
  • Humans
  • Imidazoles / pharmacology
  • Indoles / pharmacology
  • Intracellular Fluid / drug effects*
  • Intracellular Fluid / metabolism
  • Isoquinolines / pharmacology
  • Lanthanum / pharmacology
  • Maleimides / pharmacology
  • Models, Biological
  • Nifedipine / pharmacology
  • Norepinephrine / pharmacology*
  • Peptides, Cyclic / pharmacology
  • Phosphodiesterase Inhibitors / pharmacology
  • Protein Kinase C / antagonists & inhibitors
  • Pyrrolidinones / pharmacology
  • Receptors, Adrenergic, alpha-1 / genetics
  • Receptors, Adrenergic, alpha-1 / metabolism*
  • Thiourea / analogs & derivatives
  • Thiourea / pharmacology
  • Transfection

Substances

  • 2-(2-(4-(4-nitrobenzyloxy)phenyl)ethyl)isothiourea methanesulfonate
  • ADRA1A protein, human
  • Acetamides
  • Calcium Channels, L-Type
  • Estrenes
  • Imidazoles
  • Indoles
  • Isoquinolines
  • Maleimides
  • Peptides, Cyclic
  • Phosphodiesterase Inhibitors
  • Pyrrolidinones
  • Receptors, Adrenergic, alpha-1
  • YM-254890
  • lanthanum chloride
  • 1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione
  • LOE 908
  • Lanthanum
  • Protein Kinase C
  • GTP-Binding Protein alpha Subunits, Gq-G11
  • Thiourea
  • 1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole
  • Nifedipine
  • bisindolylmaleimide I
  • Calcium
  • Norepinephrine