<prompt> Which of the following is beta-blocker antagonistGlucagonNeostigmineAmbenoniumAll of the above  <response>: Ans. is a i.e., GlucagonGlucagon is used in beta-blocker poisoning to combat bradycardia produced by b-blockers. Glucagon acts by increasing C-GMP in myocardium, in effect bypassing p-receptors Action is independent of beta receptors. 