Experimental Pharmacology(Virtual lab) Effect of sympathomimetics( epinephrine - norepinephrine- isoprenaline )on isolated heart of frog

1. Stimulatory drugs on
isolated heart
By Dr Sameh AM abdel-ghany

3. Alpha blockers
• Alpha 1 and alpha 2: phentolmaine,
phenoxybenzamine and tolazoline.
• Alpha 1: prozosin, doxazosin and
terazosin.
• Alpha 2: yohmbine

4. Beta blockers
• Beta1, beta2: propranolol
• Beta 1: metoprolol and atenolol
• Beta 2: butoxamine

5. Stimulation of isloated heart
with sympathomimetics
 To increase cardiac contractilty with
Sympathomimetics:
 Stimulate B1 receptors : e.g
• Adrenaline
• Noradrenaline
• Isoprenaline

6. Stimulation of heart with
Epinephrine
Steps:
1.Inject Epinephrine produces ↑ in both HR and
contractility.
2.Try other B1 stimulants e.g. Norepinephrine and
Isoprenaline
3.Inject B1- Blocker e.g Propranolol
4.Inject Epinephrine rapidly before the action of
propranolol ends No effect of epinephrine
5.Try other B1 stimulants e.g. Norepinephrine and
Isoprenaline after propranolol

14. THANK YOU