In vivo Comparison of the Duration of Action of Different Cholinomimetics on the Blood Pressure of Anaesthetized Cats

The metabolism by Acetylcholinestrase
Carbacol

Neostigmine mechanism of action
Duration of action
neostigmine > carbachol > acetylcholine.

Principle and Assignment
Acetylcholine (Ach) and other cholinomimetics differ in the rate of metabolic clearance, which in turn affects their duration of action.
The blood pressure of anaesthetized cats was recorded following the administration of a single concentration of Ach, carbachol (Cch) or neostigmine (Neo) and results were presented in the following figure.
Determine the duration of hypotensive action of each agent and explain your results.

Assignment

In vivo Identification of Angiotensin II Receptor Blockers on Pithed Rats Blood Pressure

Principle:
Injection of Angiotensin II (AngII) into pithed rats elevates the blood pressure via its angiotensin II receptors.
Compounds which block angiotensin II receptors will prevent this rise in blood pressure.
Pithing of the rats eliminates barorecptors reflexes.

Assignment:
Compound A57 was evaluated in pithed rats for its angiotensin II receptors blocking activity. Consider the following figures and calculate the percentage reduction in blood pressure by each concentration of A57, and determine the ED50 of this compound .