Pharm for Motility Disorders Flashcards Preview

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Flashcards in Pharm for Motility Disorders Deck (25)
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0
Q

What are two levels of nervous control of esophagus motility?

A

Mostly vagus control.

Enteric neurons relay signals to the smooth muscle.

1
Q

Which part of the bowel is particularly sensitive to constipation / fecal incontinence after spinal cord trauma?

A

The rectum, as it has less intrinsic control.

2
Q

Review: What is the gradient of neuron cell types in the esophagus like?

A

More cholinergic neurons proximal.

More non-cholinergic (most NO-ergic) neurons distal.

3
Q

What are 2 ways to modify esophagus motility?

A

Reduce LESP.

Reduce vigor of lower esophageal contractions.

4
Q

3 pathophysiological causes of achalasia?

A

Loss of inhibitory, NO-ergic neurons of the myenteric plexus.
Degeneration of dorsal vagal nerve/plexus.
Dorsal vagal nucleus lesion.

5
Q

Treatments for achalasia?

A

Botox injections -> relaxation (don’t work well).

Heller myotomy - cut the LES.

6
Q

What’s a pharmacological way to decrease the vigor of esophageal contractions?

A

5’-phosphodiesterase (5-PDE) inhibitors (eg. Viagra).

These cause smooth muscle relaxation.

7
Q

If for some reason you ever do a vagotomy, what must you also do?

A

Pyloroplasty - cut open the pyloric sphincter so that stuff can get out of the stomach.

8
Q

What are the cells that mainly drive gastric motility?

A

ICCs - interstitial cells of Cajal

9
Q

What are the serotonin receptors on excitatory neurons in the gut? (name 2)

A

5-HT3

5-HT4

10
Q

What are 5-HT receptors on inhibitory neurons in the gut? (name 3)

A

5-HT7
5-HT1D
5-HT1A

11
Q

What cells in the gut secrete serotonin in response to mechanical pressure?

A

Enterochromaffin cells.

12
Q

What’s the cell / signaling pathway from mechanical pressure in the gut to contraction?

A

Pressure -> ECs secrete 5-HT -> IPAN cells -> interneurons

Interneurons act on excitatory (Cholinergic) and inhibitory (NO-ergic) motor neurons.

13
Q

Three ways to alter gastric motility?

A

Speed up gastric emptying.
Delay gastric emptying.
Improve fundic accomodation.

14
Q

How does metroclopramide (Reglan) work? What does it do?

A

5-HT4 agonist.
Dopamine antagonist.
Improves gastric emptying and is an antiemetic.

15
Q

2 classes of drugs that slow gastric emptying? (examples?)

A
Anticholinergics (Dicyclomine, Hyoscyamine)
Somatostatin analogs (Octreotide) - inhibit 5-HT and motilin release.
16
Q

What’s a drug that improves fundic and pyloric accomodation? What is it’s mechanism?

A

Buspirone - 5HT1A receptor agonist (which inhibits 5-HT release and increases NO release)

17
Q

Does diarrhea necessarily mean increased motility and constipation decreased motility?

A

No… there can periodically be the opposite. But this concept isn’t actionable yet.

18
Q

How do most common, over-the-counter laxatives work?

A

By drawing water into the bowel.

Except for “stimulant” laxatives, which irritate the bowel.

19
Q

How does lubriprostone help constipation?

A

Activates Cl- channel for increased Cl- secretion into the lumen, which water follows. (it gives you Cholera. but not really)

20
Q

How does tagaserod relieve constipation?

A

5-HT4 partial agonist.

21
Q

Are tap water / soapy water enemas a good idea?

A

Nope.
Tap water -> “water intoxication” (hyponatremia?)
Soapy water -> colitis / necrosis.

22
Q

Which antiemetic is a 5-HT3 antagonist?

A

ondansetron (Zofram)

23
Q

How can you get the anti-emetic effects of marijuana without smoking it?

A

Dronabinol.

24
Q

What receptor do pro-emetic sensors in the stomach use?

A

5-HT3