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Flashcards in ANS Drugs Deck (61)
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1

Transmitters released at ANS synapses

Acetylcholine
Norepinephrine
Dopamine

2

Which ANS synapses release acetylcholine

All preganglionic neurons
All parasympathetic postganglionic neurons
A few sympathetic postganglionic neurons

3

Which ANS synapses release NE

Most sympathetic neurons

4

Which ANS synpases release dopamine

Sympathetic fibers that innervate the renal vasculature and some other vessel beds

5

What is the predominant tone of the heart?

Parasympathetic

6

Different types of nicotinic receptor?

Neuronal -- the one at the ans ganglia

Muscular -- the one at the NMJ

7

Different types of muscarinic receptor

M2 M4 are coupled to Gi and Go

M1, 3, 5 are coupled to Gq
These activate PLC, which cleave DAG and IP3, which cause Ca release and stimulate PKC

8

A1 receptor cascade

Coupled to Gq. Elevate intracellular Ca 2 and stimulate protein kinase C. Contract smooth muscles. Also cause miosis.

9

Where do B1 receptors predominate

In the heart and in JG cells

10

Where do B2 receptors predominate?

In the vasculature, in bronchial smooth muscle.

Mediate vasodilation and bronchodilation

11

Where are Dopamine receptors

Prominent on the renal vasculature and mediate vascodilation

12

How is EPI/NE released from adrenals?

Behaves with a sympathetic ganglion. ACh released to adrenals, Adrenals release NE and EPI.

13

Baroreceptor reflex

Baroreceptors sense decrease/increase in BP, change heart rate to match .

14

Sympathetic activity effect on the vasculature

Net increase in total peripheral resistance, decrease in venous capacitance.

15

Where do beta receptors predominate in the vasculature.

Coronaries and skeletal muscles (where needed during sympathetic outflow).

16

Why is renal function preserved in flight/flight?

Because DA released in sympathetic outflow on renal vasculature causes vasodilation

17

Effects of sympathetic activity on the heart

Mediated by B1 receptors in ventricles and B2 receptors in the atria/sa node. Positive chronotropy, positive inotropy, positive lusitrophy

18

How does B stimulation increase chronotropy

Increases cAMP, which increases activity of funny current. Drives to threshold quicker

19

What is the channel that opposes the funny current?

GIRK.

20

How does B stimulation increase AV nodal propagation?

Because cAMP activates PKA, which phosphorylates L-type Ca channels, causing them to open and allow more Ca out. More rapid action potential and faster propagation.

21

How does B stimulation increase inotropy and lusitropy?

P the phospholamban. Higher ca in er. More available for release, pushed out of cell quickly.

22

Epinephrine acts on... and causes...

B1, B2, B3, A1, A2 agonist
At high doses causes vasoconstriction (increases mean BP) and increases HR. Direct effects predominate over reflex

At low doses, diastolic BP is decreased because it is more potent at B2 than A1.

23

Epinephrine at low doses

Decreases diastolic BP because epinephrine has great activity at B2 relative to A2. So will dilate.. ya know?

24

Uses for epi

Cardiac arrest, inotropic support.

Acute asthma, analphylaxis.

Prolong action of local anesthetic because causes vasoconstriciton at high doses

25

NE

A1, A2, B1
(no activity at B2)

Increases BP more than Epi.

DECREASES heart rate due to strong pressor effect.

Inotropic effect is still intact.

26

Uses of NE

Cardiogenic shock
Septic/hypovolemic shock

27

Adverse effects of NE

Severe hypertension, reduced renal flow.

Necrosis and tissue sloughing after IV injection due to extravasation of the drug (look for blanching)!

28

Isoproterenol

B1, B2, B3 agonist.

Potent vasodilator (B2).

Increases HR substantially reflex is in same direction as direct, inotropy. Decreases both diastolic and MAP.
Decreases or slightly increases systolic pressure.

29

Uses of isoproterenol

Treatment of bradycardia in heart transplant patients.
Can treat some arrhythmias (torsades)

30

Adverse effects of isoproterenol

Palpitations, tachycardia, cardiac ischemia, flushing