Regulation of the Cardiovascular System

Question 1

7-transmembrane-spanning integral membrane proteins

Extremely important for intracellular signaling throughout body

Answer 1

G protein-coupled receptors (GPCRs)

Question 2

used to treat arrhythmias, hypertension, and for cardioprotection post-MI
many subtypes

Answer 2

b blockers

GPCRs are the most prevalent drug target!

Question 3

used to treat hypertension and heart failure

Answer 3

angiotensin II receptor blockers

GPCRs are the most prevalent drug target!

Question 4

stimulatory G protein

activates adenylate cyclase

ncreases cAMP, activates PIKA

Answer 4

Gs

Question 5

inhibitory G protein

inhibits adenylate cyclase

Decreases cAMP, inhibits PKA

Answer 5

Gi/o

Question 6

activates PLC and PKC

Increases Ca2+ (via IP3R activation & SR Ca2+ release)

Answer 6

Gq

Question 7

Sympathetic stimulation increases inotropy

Little parasympathetic regulation of ______

Answer 7

inotropy

Question 8

Sympathetic stimulation increases inotropy via ________ of 4 proteins involved in EC coupling.

Answer 8

PKA phosphorylation

Question 9

relieves inhibition of SERCA
faster Ca2+ reuptake into SR.
Increases lusitropy.
Increases inotropy by increasing SR Ca2+ load.

Answer 9

PKA phosphorylation of Phospholamban (PLB)

Question 10

_______ stimulation increases inotropy

Little parasympathetic regulation of inotropy

Answer 10

Sympathetic

Question 11

Phosphorylation increases Ca2+ sensitivity,

Increases inotropy by increasing SR Ca2+ release.

Answer 11

PKA phosphorylation of Ryanodine Receptor (RyR)

Question 12

Phosphorylation slows inactivation, increases entry of trigger Ca2+
Increased Ca2+-induced Ca2+ release increases inotropy

Answer 12

PKA phosphorylation of L-type Ca2+ channel (DHPR)

Question 13

decreases Ca2+ sensitivity of troponin C

allows faster dissociation of Ca2+ so faster filling = increased lusitropy (not inotropy)

Answer 13

PKA phosphorylation of Troponin I (TnI)

Question 14

chronotropy

Answer 14

Chronotropic effects are those that change the heart rate.

Question 15

Propranolol blocks β adrenergic receptors ___________

Answer 15

(sympathetic)

Question 16

Atropine blocks muscarinic ACh receptors _________

Answer 16

(parasympathetic)

Question 17

Net inward (depolarizing) current = cardiac “funny current,” If
Promotes excitability and spontaneous action potentials
Highly expressed in sinoatrial myocytes
Activity increased by sympathetic stimulation via cAMP binding

Answer 17

HCNs

Question 18

Contractile proteins in striated muscle are organized in sarcomeres

Answer 18

Actin thin filaments

Myosin thick filaments

Question 19

Small mononucleate cells
No sarcomeres
No troponin complex, no tropomyosin
Ca2+ release from SR not required

Answer 19

Vascular Smooth Muscle Cells (VSMCs)

Question 20

Contraction triggered by mechanical, chemical, or electrical stimuli (APs not required)

Answer 20

Smooth Muscle Contraction: THICK filament regulation

Question 21

Ca2+- CaM binds to ________, to activate it. when activated, phosphorylates the myosin head permits cross bridge cycling in smooth muscle

Answer 21

Myosin Light Chain Kinase (MLCK)

Question 22

MLC dephosphorylated by Myosin Light Chain Phosphatase (MLCP), to ______

Answer 22

halt contraction in smooth muscle

**cAMP (via PKA) inhibits MLCK – causes VSMC relaxation

Question 23

cAMP (via PKA) inhibits MLCK – causes __________

Answer 23

VSMC relaxation

Question 24

Sympathetic stimulation =

Answer 24

VASOCONSTRICTION (usually)

Question 25

Baroreceptor reflex =

Answer 25

SHORT TERM and rapid negative feedback mechanism for sudden changes in blood pressure.

Question 26

cAMP (via PKA) inhibits _________– causes VSMC relaxation

Answer 26

Myosin Light Chain Kinase (MLCK)