Webb Lecture 1: GI

Question 1

inputs to the emetic/vomiting center (medulla)

Answer 1

1. CNS: witness/perceive something
2. vestibular system: feeling out of balance
3. GI tract: bunches of fibers going up CNS to emetic center
4. CRTZ: chemoreceptor trigger zone

Question 2

where is the emetic center?

Answer 2

medulla

Question 3

what activates the CRTZ?

Answer 3

drugs, toxins, pH, metabolites

Question 4

what activates the cerebral cortex?

Answer 4

scary movies, gross visuals, smells, thoughts

Question 5

what activates the vestibular apparatus?

Answer 5

motion sickness, vestibular disease, inner ear infections

Question 6

what activates the GI tract?

Answer 6

inflammation, irritation, stimulation, constipation

Question 7

how can apomorphine be administered?

Answer 7

conjunctively, or IV

Question 8

what type of drug is apomorphine?

Answer 8

powerful dopaminergic (D2) agonist: acts as ligand for R

Question 9

D2

Answer 9

Dopaminergic

Question 10

H1

Answer 10

Histamingergic

Question 11

a2

Answer 11

adrenergic

Question 12

5-HT3

Answer 12

serotonergic

Question 13

M1

Answer 13

muscarinic (ACh)

Question 14

NK1

Answer 14

neurokinergic

Question 15

ENKuy

Answer 15

enkephalinergic

Question 16

why should you not give cats apomorphine?

Answer 16

they don’t have dopaminergic receptors in their CRTZ! don’t vomit when given apomorphine, but because they have them other places in their body, causes them to go batshit crazy

Question 17

you see a 12 year old cat, Mittens, for uncontrolled vomiting after eating a billion hairties. what drug are you NOT going to reach for to induce vomiting?

Answer 17

apomorphine: cats don’t have D2 receptors

Question 18

cerenia is an anti-emetic that works because it is what type of drug?

Answer 18

NK-1 antagonist

Question 19

all inputs to the emetic center contain NK1 receptors except

Answer 19

vestibular system: only H1, M1

Question 20

most frequently used anti-emetics in vetmed

Answer 20

maropitant, ondansetron

Question 21

maropitant

Answer 21

cerenia!!

Question 22

what type of drug is maropitant

Answer 22

neurokinin-1 (MK1) receptor ANTAGONIST

Question 23

maropitant is well-tolerated in both dogs and cats, but in both species it may cause ________ during injection

Answer 23

pain

Question 24

what is the role of proton pumps in parietal cells?

Answer 24

shoves H+ ion into lumen

Question 25

what is the role of H2 receptors on parietal cells in the stomach lumen?

Answer 25

histamine: Histamine binding to the histamine (H2) receptor on parietal cells activates adenylate cyclase causing a rise in cyclic adenosine monophosphate (cAMP), which induces translocation of the H+/K+ exchange ATPase pump to the apical membrane, thus increasing proton secretion into the gastric lumen and lowering the gastric pH.

Question 26

what happens if you interfere with either the proton pump or the H2 receptors on parietal cells?

Answer 26

it can decrease the acidity in the stomach and help with nausea

Question 27

what do parietal cells do?

Answer 27

secrete gastric acid into stomach lumen

Question 28

what drug is an H2 receptor antagonist?

Answer 28

famotidine

Question 29

what drug is a proton pump inhibitor?

Answer 29

omeprazole

Question 30

what is famotidine MOA

Answer 30

H2 receptor antagonist

Question 31

what is omeprazole MOA

Answer 31

proton pump inhibitor

Question 32

cyproheptadine

Answer 32

antihistamine, but side effects are that the pt would get hungry: was used as appetite stimulant. not used a lot now. is a serotonin antagonist

Question 33

what type of drug is a serotonin antagonist that used to be used as an appetite stimulant?

Answer 33

cyproheptadine

Question 34

what type of drug is mirtazapine?

Answer 34

5-HT3 antagonist: serotonin antagonist

Question 35

mirtazapine

Answer 35

• appetite stimulant
• anti-anxiety, antidepressant esp in humans
• improved sexual motivation tests on rats
• anti-emetic (anti nausea): 5-HT3 antagonist

Question 36

what has changed with the dosing of mirtazapine in vetmed?

Answer 36

old dose used to be every 3 days, but lately studies have shown that it needs to be given every day

Question 37

Remeron SolTab

Answer 37

generic Mirtazapine

Question 38

how does the dose of mirtazapine change with patients in chronic renal failure?

Answer 38

• 1/8th tab/cat PO q24h (1.87mg)
• 1/8th tab/cat PO q48h in cats with CRF

Question 39

mirtazapine toxicity in cats

Answer 39

• occurs most frequently at 1/4 tab (3.75mg) dose
• usually reversible with discontinuation
• serotonin syndrome: vocalizing, hyperactivity, agitation, tachycardia

Question 40

how should you NEVER give diazepam/valium?

Answer 40

ORALLY! WILL KILL YOUR CAT
can give IV tho

Question 41

what medication can you NEVER given orally in a cat?

Answer 41

diazepam/valium