The effects of cardioselective and non-selective beta-adrenoceptor blockade on the hypokalaemic and cardiovascular responses to adrenomedullary hormones in man

Clin Sci (Lond). 1983 Aug;65(2):143-7. doi: 10.1042/cs0650143.

Abstract

Adrenaline was infused intravenously in nine normal volunteers to plasma concentrations similar to those found after myocardial infarction. This study was undertaken on three occasions after 5 days' treatment with placebo or the beta-adrenoceptor antagonists, atenolol or timolol. Adrenaline increased the systolic pressure by 11 mmHg, decreased the diastolic pressure by 14 mmHg, and increased the heart rate by 7 beats/min. These changes were prevented by atenolol. However, after timolol the diastolic pressure rose (+19 mmHg) and heart rate fell (-8 beats/min). Adrenaline caused the corrected QT interval (QTc) to lengthen (0.36 +/- 0.02 s to 0.41 +/- 0.06 s). No significant changes were found in the QTc when subjects were pretreated with atenolol or timolol. The serum potassium fell from 4.06 to 3.22 mmol/l after adrenaline. Serum potassium fell to a lesser extent to 3.67 mmol/l after atenolol and actually increased to 4.25 mmol/l after timolol. Adrenaline-mediated hypokalaemia appears to result from the stimulation of a beta 2-adrenoceptor linked to membrane Na+/K+-ATPase causing potassium influx.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Atenolol / pharmacology*
  • Blood Pressure / drug effects
  • Epinephrine / blood*
  • Heart Rate / drug effects
  • Humans
  • Hypokalemia / etiology
  • Male
  • Myocardial Infarction / blood
  • Myocardial Infarction / complications
  • Potassium / blood*
  • Propanolamines / pharmacology*
  • Timolol / pharmacology*

Substances

  • Propanolamines
  • Atenolol
  • Timolol
  • Potassium
  • Epinephrine