title: [Modulation of protein kinase A and protein kinase C on the delayed rectifier potassium current in guinea pig ventricular myocytes].
abstract: OBJECTIVE
  To study modulation of protein kinase A (PKA) and protein kinase C (PKC) on the delayed rectifier potassium current (Ik)in guinea pig ventricular myocytes.
  
  
  METHODS
  The delayed rectifier potassium current was recorded by using whole cell arrangement of the patch-clamp procedure.
  
  
  RESULTS
  cAMP 150 micromol/L increased intracellularly Ik and Ik,tail(pA/pF) from 13.7 +/- 2.1 and 6.1 +/- 0.1 to 18.5 +/- 3.3 and 6.4 +/- 2.1 (P < 0.01, n=6). Ik and Ik,tail(pA/pF) were augmented by 8-CPT-cAMP 150 micromol/L extracellularly from 11.4 +/- 1.8 and 5.3 +/- 0.6 to 17.9 +/- 4.0 and 6.2 +/- 1.3. The half-maximal voltage of activation of Ik was shifted from + 23.3 mV to 18.7 mV by cAMP. Phorbol 12-myristate 13-acetate(PMA, 10.0 micromol/L) applied intracellularly caused an enhance effect on Ik, with increasing Ik and Ik,tail(pA/pF) from 12.9 +/- 1.8 and 5.0 +/- 1.7 to 23.7 +/- 2.8 and 7.5 +/- 1.1. With shifting position potential of depolarization, effect of PMA on Ik was gradually augmented. PMA resulted in shifting the slop of activation curve from +15.3 mV to +25.6 mV, with only a small effect on the half-maximal voltage of activation of Ik.
  
  
  CONCLUSIONS
  Ik was increased by both PKA and PKC, with different characteristics of regulation.
authors.affiliation: Department of Cardiology, Tongji Hospital, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Li-ying
authors.initials: LY
authors.lastname: Fu
authors.forename: Wei-xing
authors.initials: WX
authors.lastname: Yao
mesh_terms: D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000494:pharmacology*; D051668:Delayed Rectifier Potassium Channels / Q000378:metabolism*; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D011493:Protein Kinase C / Q000494:pharmacology*
chemical_list: D051668:Delayed Rectifier Potassium Channels; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D011188:Potassium