This document discusses demonstrating the effects of various drugs on blood pressure and heart rate using simulation software. It describes how vasopressors like epinephrine, norepinephrine, and isoproterenaline affect blood pressure and heart rate. Epinephrine causes an initial sharp increase in blood pressure followed by a decrease. Norepinephrine causes a sharp increase in blood pressure. Isoproterenaline decreases blood pressure. It also discusses vasodepressor drugs like acetylcholine and histamine, which decrease blood pressure.

1. PH 4.2-Demonstrate the effects of drugs on blood pressure
(vasopressor & vasodepressors with appropriate blockers) using
CAL/ charts

2. Aim: To demonstrate the effects of various drugs (vasopressor & vasodepressors
with appropriate blockers on BP & HR of perfused dog heart simulation
software.

3. Effect of Vasopressor drugs like Epinephrine, Nor-epinephrine & Isoprenaline on BP
• Epinephrine- ↑ Both BP & HR
• Nor-epinephrine- ↑BP & compensatory ↓ HR
• Isoprenaline- ↓ BP & ↑ HR due to + of β2 receptors.

5. Epinephrine (Epi)-
 On sudden Rapid IV injection it produced biphasic response
 There is marked increase BP after this it return to normal within few minute and then fall BP
 Initial phase- sharp ↑ in B.P due to + of α1 & β1 R.
 β1- increases HR & FOC  ↑CO.
 α1-vasoconstriction blood vessels ↑ TPR ↑ BP
 Secondary phase- ↓ in B.P below base line is due to + of β2R vasodilation of blood vessels ↓ TPR↓
BP before normalisation.
IV. Epi

7. Dale’s Vasomotor reversal phenomenon (due to α-blockers)
When Epi. is administered after phentolamine, the effect of Epi. gets reversed & results in ↓ BP. Its due to
α receptor mediated actions of Epi is blocked & exhibits only β2 receptor mediated effects i.e,
vasodilation↓ BP.

8. Dale’s Vasomotor re- reversal phenomenon (due to b-blockers)
• Epi. administered after propranolol, only rise BP observed because Epi. act only
predominantly mediated via α1 receptors, beta action blocked by non selective beta
blocker (propranolol).
IV. Epi
IV. Epi
Pro

9. Nor-epinephrine-
 It cause Only sharp ↑ in BP.
 ↑ in B.P due to + of α1 & β1 receptors.
 + β1R ↑ HR & FOC  ↑ CO.
 + α1R  ↑ TPR ↑ BP.

11. Isoprenaline (Isoproterenol)
• It decrease BP it has predominant β action cause vasodilatation but no α actions.

12. Vasodepressor agents
Drugs like-
• Cholinergic-Ach & Cholinomimetic esters
• Miscellaneous-Histamine
• Vasodepressors causes arteriole vasodilation via -ve inotropic or chronotropic effects
that lead to ↓ systemic vascular resistance & BP.
• Vasodepressors acts on specific cholinergic/ histaminic receptors to decrease BP.

13. Effect of vasodepressor agents like Ach & Histamine on BP
• Ach-↓ both BP
• Histamine- ↓ BP

14. Acetylcholine
 IV adm. of Ach causes sharp ↓in BP & quick normalisation.
 due to vasodilation of vascular M3R stimulation & also due to + of M2R.

16. Histamine
• Generally causes vasodilation through H1 & H2 receptors ↓BP.

17. ANS: Phenomenon of Tachyphylaxis
A rapid decrease in response to repeated doses over a short time period.