Lecture 8 Ca channel blockers

Question 1

what determines the direction of flow in an ion channel?

Answer 1

concentration and electrical gradient

Question 2

excitable cells have a ____ inward potential across the membrane due to the selective permeability of the resting membrane to ____

Answer 2

negative;

K+

Question 3

K is high ____ and low ____ the cell.
Na is high ____ and low ____ the cell.
Calcium is very low ____ and high ____ the cell

Answer 3

inside, outside;
outside, inside;
inside, outside

Question 4

2 main components of voltage gated channels:

Answer 4

selectivity filter, gate

Question 5

___ type Calcium channels are located on cardiac, smooth, and skeletal muscle

Answer 5

L

Question 6

Voltage gated calcium channels type 2 are found where? what do they do

Answer 6

neurons, trigger NT release

Question 7

The voltage gated calcium channel type _ . ___ is what is targeted by calcium channel blockers

Answer 7

1.2 (probably not very high yield tbh)

Question 8

Calcium Channel blockers (CCBs) that block channels in vascular smooth muscle cause _____. CCBs that block channels in cardiac muscle are _____

Answer 8

vasodilation; anti-arrhythmic

Question 9

vascular smooth muscle: _____ causes Calcium influx via ____ channels. this induces release of calcium from intracellular stores via _____ receptor located in the ____

Answer 9

depolarization, CaV1.2 (ie L-type);

ryanodine receptor 2; Sarcoplasmic reticulum

Question 10

extracellular calcium is required for contraction of what kind(s) of muscle? what kind(s) of muscle is extracellular Ca not required in?

Answer 10

required in cardiac/smooth muscle;

not required in skeletal muscle

Question 11

The increase in intracellular Calcium causes it to bind ___. This activates _____, which acts upon myosin light chain. ______ of myosin light chain causes it to complex with ____, causing contraction to ensue.

Answer 11

calmodulin, myosin light chain kinase;

phosphorylation, actin

Question 12

Cardiac muscle: Calcium ions released from the sarcoplasmic reticulum bind to ____. Binding of this causes displacement of ____, allowing ____ to bind ____ and contraction

Answer 12

troponin C;

tropomyosin; myosin+Actin

Question 13

what are the three chemical classes of CCBS

Answer 13

dihydroppyridines, phenylalkylamines, benzothiazepines

Question 14

all dihydropyridines end in ____

Answer 14

“-dipine” ie nifedipine, isradipine, felodipine etc

Question 15

Dihydroppyridines bind where on the receptor?

Answer 15

NOT the binding site; allosteric modulators

Question 16

______ is a dihydropyridine that has a very short half life. it is given in acute settings via IV ie HTN emergency

Answer 16

clevidipine

Question 17

what is clevidipine formulated with? (ie allergy risk)

Answer 17

soy, egg

Question 18

where do dihydropyridines (DHPs) act? they cause what?

Answer 18

vascular muscle, esp coronary arteries; vasodilation

NOT ANTI-ARRHYTHMIC

Question 19

Binding of DHPs is ____ dependent ! Why is this important?

Answer 19

voltage; smooth muscle of vasculature has elevated resting membrane potential = bind more

Question 20

DHP’s bind to _____ channels and prevent ____. This is caused ____ block

Answer 20

closed, opening;

TONIC

Question 21

DHPs preferentially vasodilate ____. This causes decreased _____

Answer 21

arterioles, afterload

Question 22

_____ is the DHP with the poorest vasodilatory action

Answer 22

nifedipine

Question 23

_____ exhibits selectivity for cerebral arteries. Use it in ______ ____ to prevent neuropathy

Answer 23

nimodipine, subarachnoid hemorrhage

Question 24

all DHPs cause ____ ____ secondary to vasodilation, except for ____, which has slow action

Answer 24

reflex tachy;

amlodipine

Question 25

Verapamil is a member of what CCB class?

Answer 25

phenylalkylamine

Question 26

Verapamil mainly ____ conduction through the SA and AV nodes, causing a reduction in ____ and ____ of contraction

Answer 26

slows; HR, force

Question 27

Where does verapamil bind on the receptor?

Answer 27

IN THE PORE

Question 28

Verapamil binds when the receptor is ____. Thus, this is called ________ block

Answer 28

OPEN;

frequency-dependent

Question 29

Diltiazem belongs to what class of CCBs?

Answer 29

benzothiazepine

Question 30

diltiazem causes _____ effect on vasodilation than verapamil (According to FA and sketchy). It causes ____ effect on the heart than verapamil

Answer 30

MORE (his notes are wrong);

less

Question 31

Characteristics of diltiazem blocking of receptor?

Answer 31

it goes both ways: some tonic, some frequency dependent block

Question 32

all three CCBs cause ____ (highlighted in his notes)

Answer 32

ankle edema

Question 33

_______ causes constipation

Answer 33

verapamil

Question 34

_____ cause facial flushing and tachy

Answer 34

DHPs

Question 35

_____ can be used in HTN in pregnant women. However, watch out for ______

Answer 35

nifedipine;

reflex tachy –> potentially increase risk of MI