L13 Flashcards Preview

P&T Block 1 > L13 > Flashcards

Flashcards in L13 Deck (32):
1

What are 2 direct vasodilator drugs

Hydralazine
Minoxidil

2

When do you use hydralizine

HFail
Acute, severe HTN

3

What drugs must you combine these direct vasodilators with?

Diuretic = combat ↑renin
BB (sympatholytic) = stop reflex tachycardia

4

SE of hydralazine

Lupus-like syndrome
Esp for pts with liver disease aka "slow acetylators" since hydralazine inactivated in liver

5

Where is minoxidil activated?

Liver via sulfonation

6

How do direct vasodilators vasodilate?

Hydralazine = ↑cGMP
Minoxidil = open Katp channels

7

Net effect of vasodilators

↓afterload

8

What is pseudo-tolerance in relation to direct vasodilators?

Get temp ↓BP
BP rebounds due to sympa reflex response: ↑HR + ↑renin

9

What 3 tissues should you remember contain Katp channels? What determines the channel's tissue specificity?

Heart
Vasc smooth muscle
Pancreatic B cells
Isoform = tissue specificity

10

Normal fxn Katp channels

Couples metabolic state of cell to its electrical activity

11

3 drugs that open Katp channels

Minoxidil
Diazoxide
Adenosine

12

Minoxidil is tissue specific for... + drug use

Vasc smooth muscle - vasodilator to ↓BP
Anti-HTN

13

Diazoxide is tissue specific for... + drug use

Pancreas - ↓insulin release
Hypoglycemia or hyperinsulinemia

14

Adenosine is tissue specific for + drug use

Cardiac = A1 receptor = anti-arrhymthic
Vasc smooth muscle = A2 receptor = dilator

15

Explain Katp channels in heart under ↓ATP

Hypoxia/E depletion = ↓ATP = ↑ADP
Avail adenosine binds A1 receptors
Katp channels open --> hyperpol membrane
NET = shorter AP, ↓contractility

16

Explain Katp channel in vasc smooth muscle under ↓ATP

Baseline vasc smooth muscle = tonically contracted
↓ATP --> open Katp
↑K+ in, ↓Ca2+ in via voltage Ca2+ channels
Hyperpol --> relaxation = vasodilation

17

How does adenosine act as vasc smooth muscle?

↓ATP = ↑ADP = ↑adenosine + A2 receptor - helps open Katp channels

18

What are 2 parts of the Katp channel in pancreatic B cells

SUR1 & Kir 6.2

19

Explain ↓blood glucose result on Katp channels in pancreas

↓BG --> ↓ATP --> Katp opens --> hyperpol --> ↓insulin release

20

Where does diazoxide binds the Katp channel in pancreas

SUR1 to open channel

21

Where does sulfonylurea bind the Katp channel in pancreas - does it open or close the receptor?

SUR1 to close channel

22

What is the action of ATP and MgADP on the Katp channel in the pancreas? Where does each bind?

ATP closes via Kir 6.2
MgADP opens via SUR 1

23

How does a gain of function Katp mutation present? Treat

Neonatal diabetes (↓insulin)
+ Sulfonylurea

24

How does a loss of fxn Katp mutation present? Treat

Neonatal hyperinsulinemia
Diazoxide

25

What is the cardioprotective mechanism of adenosine & diazoxide

Open cardiac MITOCHONDRIAL Katp channels

26

What is ischemic pre-conditioning

Post short-term coronary artery occlusion
Change myocyte fxn of tissue affected by occlusion + abnormal wall motion of normal myocardium
After reperfusion during "stunned" period, protected from long duration occlusions that are v damaging

27

What is the acute phase of ischemic preconditioning

Katp open - including mitochondrial Katp channels
Important to maintain mito fxn

28

What is the delayed phase of ischemic preconditioning

RISKinases turn on genes for protective proteins --> ↑transcription of these

29

Which during do you give during ischemic preconditiong, why?

ADENOSINE
Binds A1 receptor to help open Katp channels
- Mitochondial fxn
- ↓HR & contractility
Binds A2 - vasodilation

30

What is ischemic post-conditioning

Short periods of ischemia during reperfusion can be beneficial b/c limit extent of damage

31

What is remote pre/post conditioning

Transient ischemia of some pt of body (arm)
Liberates an unknown effector
Induces remote cell adaptation to an ischemia that isn't happening to it - get protection w/o damage

32

Which drug do you give during stress tests

Adenosine