Effect of Drugs on Blood Pressure and Heart Rate

1. Effects of Selected Drugs on the
Autonomic Regulation of
Blood Pressure and Heart Rate of
an Anaesthetized Rat
Shivankan Kakkar, MD

2. Learning Objectives
1. Understand the effects of adrenaline and acetylcholine on blood
pressure and heart rate.
2. Identify the potential effects of pre-treatment with prazosin (alpha
blocker) and propranolol (non-selective beta-blocker) on adrenaline-
induced changes in blood pressure and heart rate.
3. Identify the potential effects of pre-treatment with atropine (muscarinic
blocker) on acetylcholine-induced changes in blood pressure and heart
rate.
4. Use the CAL (computer Assisted Learning) interface to perform
experiments on adrenaline and acetylcholine alone and after pre-
treatment with other drugs.
5. Create a chart/graph of the tracings and interpret the findings from the
different experiments.
DrShivMD

3. Effect of I.V. Injections of Adrenaline alone & after Pre-treatment
with Adrenergic Antagonists on Blood pressure & Heart rate of
an Anaesthetized Rat
Exercise 1
DrShivMD

4. How to Start
• Launch the application file.
• Click on "Start."
• Select the drug “Adrenaline” in "Agonists.”
• Choose the dose “20 mcg/kg”
• Click "Inject Drug."
• Create a chart/graph of the tracings in your practical records and repeat
this step each time you use a new drug or procedure.
• Select the drug: "10 mg/kg Prazosin (alpha blocker)” in “Antagonists.”
• Select the drug: "20 mcg/kg Adrenaline."
• Select the drug: "100 mg/kg Propranolol (non-selective beta-blocker)" in
“Antagonists.”
• Select the drug: "20mcg/kg Adrenaline."
DrShivMD
Exercise 1

5. ABP
HR
20 mmHg
-1 BPM
100 s
Atr 10 mg/kg
Adr
20 mcg/kg Prazosin
10 mg/kg
Propranolol
100 mg/kg
Adr
20 mcg/kg
Adr
20 mcg/kg
Effect of I.V. Injections of Adrenaline alone & after Pre-treatment with Adrenergic Antagonists
on Blood Pressure & Heart Rate of an Anaesthetized Rat
DrShivMD
Blood
Pressure
Heart
Rate

6. Worksheet
Q.1. How does adrenaline affect blood pressure and heart rate?
______________________________________________________________
______________________________________________________________
Q.2. What is the effect of adrenaline on blood pressure and heart rate after
adding prazosin?
______________________________________________________________
______________________________________________________________
Q.3. What is the effect of adrenaline on blood pressure and heart rate after
adding propranolol?
______________________________________________________________
______________________________________________________________
Q.4. Explain the receptors responsible for the effect of adrenaline on blood
pressure and heart rate.
______________________________________________________________
______________________________________________________________
DrShivMD
Exercise 1

7. Worksheet
Q.5. Begin a new experiment by carrying out the following steps:
• Select the drug: 20 mcg/kg adrenaline.
• Select the drug: 100 mg/kg propranolol (non-selective beta-blocker).
• Select the drug: 20 mcg/kg adrenaline.
• Create a chart/graph of the tracings.
Q.6. A 56-year-old female was admitted to the hospital and diagnosed with
pheochromocytoma (a tumor that results in excess secretion of catecholamines).
The physicians need to control her blood pressure before surgery.
Which regimen is better and why?
a) Alpha-blocker followed by beta-blocker
b) Beta-blocker followed by alpha-blocker
DrShivMD
Exercise 1

8. Effect of I.V. Injections of Acetylcholine alone and after Pre-
treatment with Atropine on Blood Pressure and Heart Rate of an
Anaesthetized Rat
Exercise 2
DrShivMD

9. How to Start
• Launch the application file.
• Click on "Start."
• Select the drug “Acetylcholine” in "Agonists.”
• Choose the dose “10 mcg/kg”
• Click "Inject Drug."
• Create a chart/graph of the tracings in your practical records and repeat
this step each time you use a new drug or procedure.
• Select the drug: "20 mcg/kg Acetylcholine."
• Select the drug: "10 mg/kg Atropine (muscarinic blocker)" in
“Antagonists.”
• Select the drug: "10mcg/kg Acetylcholine."
• Select the drug: "20mcg/kg Acetylcholine."
DrShivMD
Exercise 2

10. ABP
HR
20 mmHg
-1 BPM
100 s
Atr 10 mg/kg
Blood
Pressure
Heart
Rate
ACh
10 mcg/kg ACh
20 mcg/kg
ACh
10 mcg/kg
Atropine
10 mg/kg
ACh
20 mcg/kg
Effect of I.V. Injections of Acetylcholine alone & after Pre-treatment with Atropine
on Blood Pressure & Heart Rate of an Anaesthetized Rat
DrShivMD

11. Worksheet
Q.1. How does ACh affect BP and HR?
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
Q.2. When atropine is added, what effect does ACh have on BP and
HR?
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
DrShivMD
Exercise 2

12. Worksheet
Q.3. Explain the receptors responsible for the effects of ACh on BP and HR.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
Q.4. A 35-year-old male patient arrived at the emergency department with
symptoms of organophosphate (OP) poisoning. The patient had accidentally
ingested a toxic amount of an OP pesticide commonly used in his agricultural
work. On arrival, the patient was experiencing excessive sweating, diarrhea,
and urinary incontinence.
Which treatment did the doctor prescribe to this case and why?
a) Atropine
b) Cholinesterase inhibitors (CHEIs)
c) Atropine+CHEIs
DrShivMD
Exercise 2

13. Interpreting the Findings &
Identifying the Unknown Drugs
Exercises 1 & 2
DrShivMD

14. ABP
HR
20 mmHg
-1 BPM
100 s
Atr 10 mg/kg
Drug A
20 mcg/kg
Drug B
10 mg/kg
Drug C
100 mg/kg
Drug A
20 mcg/kg
Drug A
20 mcg/kg
Effect of I.V. Injections of Selected Drugs
on Blood Pressure & Heart Rate of an Anaesthetized Rat
DrShivMD
Blood
Pressure
Heart
Rate

15. ABP
HR
20 mmHg
-1 BPM
100 s
Atr 10 mg/kg
Blood
Pressure
Heart
Rate
Drug X
10 mcg/kg Drug X
20 mcg/kg
Drug X
10 mcg/kg
Drug Y
10 mg/kg
Drug X
20 mcg/kg
Effect of I.V. Injections of Selected Drugs
on Blood Pressure & Heart Rate of an Anaesthetized Rat
DrShivMD