Lecture 8: Autonomic Pharmacology Flashcards Preview

Neuro I Exam 3 - Physiology > Lecture 8: Autonomic Pharmacology > Flashcards

Flashcards in Lecture 8: Autonomic Pharmacology Deck (41)
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1

What is the NT and receptors for the Parasympathetics?

NT: ACh

Receptors: nAChR and mAChR

2

What is the NT and receptors for the Sympathetics?

NT: NE>Epi (DA); ACh

Receptors: α,β, (D), nAChR, mAChR

3

Dopamine is the precursor to NE and Epi, where does it exert its actions?

Acts on the CNS and renal vascular smooth muscle

4

All preganglionic autonomic fibers use what NT?

ACh (cholinergic)

5

All post-ganglionic parasympathetics utilize what NT?

ACh

6

What are the 3 cholinergic receptors that are GPCR, Gq/11; what cascade results from activation of these receptors?

- M1

- M3

- M5

* All activate PLC; IP3; DAG cascase

7

What are the 2 cholinergic receptors that are GPCR, Gi/o; what is the cascade that occurs upon activation of these receptors?

- M2

- M4

* Inhibition of adenylyl cyclase (AC); decreased cAMP, activation of K+ channels

8

What is the location of M1-M5 cholinergic receptors?

M1: CNS, ganglia

M2: Heart, nerves, smooth muscle

M3: Glands, smooth muscle, endothelium

M4: CNS

M5: CNS

9

What kind of receptor is the Alpha 1 and what are its agonists?

- Gq; increased PLC; IP3; DAG; Ca2+

- Epi ≥ NE 

10

Activation of the β3 receptor primarily causes what and where are they found; which agonist preferentially acts on this receptor?

- Found in adipose tissue

- Activation results in lipolysis

- NE is the agonist

11

The β2 receptor responds best to what agonist and where are these receptors found?

- Epi >> NE

- Smooth muscle (vascular, bronchial, GI, GU), skeletal muscle

- Relaxaton and Glycogenolysis; uptake of K+

12

What does stimulation of the alpha-1 receptor do to smooth muscle, vascular smooth muscle, and glandular smooth muscle (rules to live by)?

- Stimulate contraction of all smooth muscle

- Vascular smooth muscle - vasoconstriction

- Glandular smooth muscle - secretion

13

What does stimulation of the beta-2 receptor do to smooth muscle (rules to live by)?

Relax smooth muscle - vasodilation

14

What does stimulation of the Muscarinic receptors do to smooth muscle (rules to live by)?

- Contract smooth muscle

- ACh and muscarinic agonists given IV cause vasodilation due to release of nitric oxide (NO)

15

ACh and muscarinic agonists given IV will cause what?

- You get contraction of smooth muscle

- BUT, also get vasodilation due to the release of nitric oxide (NO)

16

What are 5 effects of the parasympathetics?

1) Salivation, lacrimation

2) Pupil constriction (myosis)

3) Decrease in HR

4) Urination, defecation

5) Increased secretion and motility

*Cholinergic

17

What are 5 effects of the sympathetics?

1) Cutaneous vasodilation

2) Pupil dilation (mydriasis)

3) Increase in HR

4) Reduction/elimination of the desire to urinate

5) Decreased secretion and motility

*Adrenergic

18

In general activation of alpha-2 receptors results in what?

- Vascular smooth muscle contraction

- Decreased insulin secretion

- Decreased release of NE (pre-synaptic α2 receptors)

19

β1 receptors are mainly found where and activation causes?

- Mainly found in the myocardium

- Increased force and rate of heart contraction and AV nodal conduction velocity

20

β2 receptors are mainly found where and activation causes?

- Mainly found on smooth muscle and most other sites

- Activation causes: vascular, bronchial, genitourinary, and GI smooth muscle RELAXATION

21

In a patient with an overactive parasympathetic NS presenting with worsening urinary incontinence what is the drug of choice?

- mAChR antagonist

- Will cause relaxation and inhibit bladder contraction

22

How is activation of the mAChR's able to cause trigone and sphincter relaxation?

- Normally associated with contraction of smooth muscle

- BUT, also leads to vasodilation due to release of nitric oxide (NO)

23

What are adverse effects that may be seen after treatment with a non-selective mAChR antagonist?

Constipation, dry mouth/eyes, dizziness, and blurred vision

24

Why does the administration of non-selective mAChR antagonists lead to blurred vision?

- Contraction of the ciliary muscle of eye is PNS mediated (cholinergic)

- Loss of contraction of ciliary muscle = lens stays flat = decreased abillity to focus and loss of near vision

25

A patient presents with worsening COPD, what type of drug is best in this situation?

- A mAChR antagonist

- Will block the contraction of the bronchial smooth muscle

26

Tiotropium is an inhaled (mAChR antagonist), what is a common side effect of this drug?

- Decreased mucus production

- You are blocking a parasympathetic receptor, remember, the PNS is responsible for rest and digest!

27

A patient has a positive fractionated free metanephrine test and a 24-hour urine specimen supports this dx; what is the patients condition?

- Pheochromocytoma

- An endocrine tumor that secretes catecholamines

28

The patient with a pheochromocytoma presents with headache, increased perspiration, palpitations, and a significantly increased BP, what drug should be used to decrease the BP?

Alpha-1 antagonist

29

The patient with a pheochromocytoma presents with headache, increased perspiration, palpitations, and a significantly increased BP, an antagonist of which receptor will most likely reduce her HR?

Beta-1 receptor antagonist

30

The patient with a pheochromocytoma presents with headache, increased perspiration, palpitations, and a significantly increased BP,after administration of a beta-receptor selective antagonist (propranolol) what do you expect to happen and why?

- Worsening of HTN 

- This is known as unopposed alpha stimulation

- Since the pheochromocytoma is secreting catecholamines, you must block both the alpha and beta receptors.

- Only blocking the beta receptor will slow down the heart rate, but the BP will likely increase due to catecholamines acting on the alpha-1 receptor.