L09-Autonomic Pharmacology Flashcards
What are the neurotransmitters for the sympathetic and parasympathetic nervous systems?
For sympathetic the preganglionic are Ach and post ganglionic is NA. (exception of sweat glands that are Ach)
For parasympathetic both are Ach
What are the effects of sympathetic stimulation on the cardiovascular system?
- increased heart rate and contractility (B1)
- Vasoconstriction (a1 and a2) - periphery
- some vasodilation (B2) - muscles
- Regulations of renin release for volume control (B1)
What effects do beta agonists have on the heart?
- Increased ICa,L (Ca2+ channel) for greater Ca2+ entry
- Increased IK for faster repolarization
- Increased Na+/K+ ATPase activity
- Increased If (funny current) for positive chronotropy
- Increased ER Ca2+ uptake
- Increased Ca2+ sensitivity
What is adrenaline used to treat?
Asystole, ventricular fibrillation and other severe arrhythmias
Anaphylaxis
What is dobutamine used to treat?
it is a B1 agonist so is used to treat cardiogenic shock
What is phenylephrine and what is it used to treat?
It is an alpha 1 agonist so is found in things like sudafed that treat nasal congestion by constricting vessels.
What is doxazosin and what is it used to treat?
It is an alpha 1 antagonist so causes vasodilation of peripheral vessels. This is used to treat hypertension and raynauds syndrome.
What is propranolol and what is it used to treat?
It is a beta 1 and 2 antagonist so negative chronotropic and inotropic effects. This decreases the work done by the heart so is used to treat patients with angina, heart failure (allowing time for ventricles to fill), cardiac arrythmias and hypertension.
What is carvedilol and what is it used to treat?
It is a mixed alpha and beta antagonist so is used to treat heart failure.
What are the three main reasons that beta blockers decrease BP?
They reduce the cardiac output through decreasing ionotropy and chronotropy.
They reduce renin release from the kidneys (fluid retention) through blocking B1 receptors on the kidneys)
They inhibit the trophic effects of catecholamines on the heart (stop atrophy)
What are the cardiovascular effects of parasympathetic stimulation on the heart?
Negative chronotropic effects through acting on the SAN also slowing AVN conduction
What is atropine and what is it used to treat in the CVS?
it is a muscarinic antagonist so blocks the effect of M2 receptors on the heart. This is key to treating superventricular bradycardia.
Other effects are decreased secretions and bronchodilation.
What are proarhythmic effects?
The increased occurrence of preexisting arrhythmias
What effect does cocaine have on the heart?
Affects the reuptake of Noradrenaline resulting in proarrhythmic effects
How do amphetamines work?
They act as sympathemimetics and reverse noradrenaline transport that causes its release.
