The effects of parathyroid hormone on L-type voltage-dependent calcium channel currents in vascular smooth muscle cells and ventricular myocytes are mediated by a cyclic AMP dependent mechanism.
The present study demonstrated that L channel currents were decreased in smooth muscle cells, and increased in ventricular myocytes by both bovine parathyroid hormone, (bPTH-(1-34)), and dibutyryl cyclic AMP (db-cAMP), using the whole cell version of the patch clamp technique with Ba2+ as the charge carrier. The effects of bPTH-(1-34) and db-cAMP on L channel currents were additive but not synergistic. Furthermore, the effects of bPTH-(1-34) on L channel currents in these 2 cell preparations were abolished in the presence of a cAMP antagonist. These results suggest that the effects of bPTH-(1-34) on L channel currents in vascular smooth muscle cells and ventricular myocytes are mediated by a cAMP-dependent mechanism.
Wang
R
R
Department of Physiology, University of Alberta, Edmonton, Canada.
Wu
L Y
LY
Karpinski
E
E
Pang
P K
PK
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D000242:Cyclic AMP / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects*; D008564:Membrane Potentials; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D010281:Parathyroid Hormone / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D015220:Calcium Channels; D010281:Parathyroid Hormone; D003994:Bucladesine; D000242:Cyclic AMP