Ans- Drugs

Question 1

What is an example of a drug which works at the ganglia to cause vasodilation?

Answer 1

Trimetaphan- competitive antagonist of the nicotinic action of ACH in the ganglia

Question 2

What are two strategies used to stimulate parasympathetic activity?

Answer 2

1) muscarinic agonists

2) anticholinesterases

Question 3

What are the two types of muscarinic agonists?

Answer 3

Esters of choline: metacoline, carbamic acid, carbacol, betanechol
Alkaloids based on muscarine (pilocarpine)

Question 4

Name muscarinic antagonists

Answer 4

Glycopyrrolate, hyoscine, homatropine, atropine

Question 5

What are the effects of atropine in the various systems (CNS, CVS, GIT and respiratory)

Answer 5

CNS: atropine is a mild stimulant
CVS: cause ps a tachycardia, unopposed sympathetic drive. Only give atropine during a bradycardia for a Vagal cause
Respiratory: reduces secretions, bronchodilator
GIT: reduction is secretion of gastric and gastric acid. Decrease in salivation and GI motility

Question 6

Which sympathetic receptors does adrenaline predominantly work on and what is its effect?

Answer 6

B2 receptors in the coronary vessels and heart which causes dilatation

Question 7

Which receptors does noradrenaline predominantly work on and what is its effect?

Answer 7

Noradrenaline is more potent at the a1 receptor and causes a rise in SVR, systolic and diastolic pressure

Question 8

Which receptors do dobutamine and dopamine act on?

Answer 8

Dopamine:B2 at low doses and both a1 and b2 at high doses
Dobutamine: B1

Question 9

What are the indirect and direct effects of ephedrine?

Answer 9

Primary action: release noradrenaline from sympathetic terminals
Secondary: direct effect on a and b receptors resulting in vasoconstriction and increased cardiac output

Question 10

What are the effects of phenylephrine?

Answer 10

It is selective for a1 receptors and causes vasoconstriction and increased SVR