Vascular smooth muscle Flashcards

1
Q

List the major classes of antihypertension drugs

A
  • Diuretics
  • Adrenoceptor antagonist
  • Angiotensin converting enzyme inhibitors
  • Angiotensin receptor antagonist
  • Calcium channel blockers
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2
Q

Hypertensin

A

High blood pressure

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3
Q

Activation of the sympathetic nervous system and the renin-angiotensin system releases what?

A

Vasocontrictor hormones: adrenaline, noradrenaline and angiotensin(ii)

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4
Q

What does adrenaline, noradrenaline and angiotensin(ii) activate?

A

Specific receptors that increase intracellular [Ca2+] that causes vascular SM contraction.

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5
Q

What is the use of Rho kinase and protein kinase C in hormone induced vascular smooth muscle?

A

Will cause the contraction of SM to be sustained at low Ca2+ levels.

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6
Q

What two things prolong the hormone induced SM contraction

A

Rho kinase and protein kinase C

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7
Q

‘vasodilators’ are antihypertensive drugs

A

True

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8
Q

What do antihypertensive drugs do?

A

Increase the diameter of blood vessels (relax) and reduce vascular resistence & blood pressure.

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9
Q

Antihypertensives that increase the diameter of blood directly.

A
  • Beta-adrenoceptor agonist
  • Nitric oxide donors
  • Nitric oxide gereators
  • K+ channel openers
  • Phosphodiesterase inhibitors
  • guanylate cyclase stimulators
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10
Q

ANtihypertensive drugs that increase BV diameter by inhibiting endogensous vc substanes.

A
  • ACE inhibitors
  • Angiotensin receptor antagonist
  • Alpha-adrenoceptor antagonist
  • Calcium channel blockers
  • Rho kinase inhibitors

Will block stuff like NA and angiotensin II

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11
Q

What does contraction of vascular smooth muscle cause?

A

Increased vascular resistence and increase in blood pressure.

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12
Q

Prasozin

A

alpha-1-adrenoceptor antagonist

Block phenylephrine contraction

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13
Q

Atenolol

A
  • beta-antagonist
  • antagonist to sympathetic innervation
  • prevents increases in heart rate, electrical conductivity, and contractility in the heart due to increased release of NA from the peripheral NS.
  • Decrease BP
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14
Q

Celiprolol

A

it is a selective β1 receptor antagonist, but a β2 receptor partial agonist. It is also a weak α2 receptor antagonist

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15
Q

Labetolol

A

combined alpha- and beta-adrenoceptor blocking agent

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16
Q

Prazosin found

A
  • Prazosin is an alpha-1 adrenergic receptor antagonist.
  • Alpha-1-receptors are present on smooth muscle, as in the blood vessel walls, iris dilator muscle, and brain.
  • Alpha 1 antagonists cause smooth muscle relaxation, which can, in turn, cause a decrease in blood pressure by decreasing systemic vascular resistance. This medication can also cross the blood-brain barrier
  • decrease in total peripheral resistance
17
Q

Atenolol found

A
  • a beta-1 adrenergic antagonist, selectively binds to the beta-1 adrenergic receptors in vascular smooth muscle and the heart.
  • block NA and ADN
  • This activity results in a decrease in heart rate, blood pressure, and myocardial contractility.
18
Q

Labetolol found

A
  • alpha1-adrenergic antagonism and
  • non-selective, competitive, beta-adrenergic (B1 and B2) block
  • intrinsic sympathomimetic activity
  • decreased peripheral vascular resistance without significantly altering heart rate or cardiac output.
    *
19
Q

Celiprolol found

A
  • beta1-andrenoceptor antagonist with partial beta2 agonist activity
  • reduces arteriolar resistance and improves blood flow without depressing cardiac function.
  • weak α2 receptor antagonist

Block NA and ADREN

20
Q

Nicorandil found

A
  • vasodilatory drug that functions through potassium channels opener and intracellular cGMP concentrations commonly used to treat angina.
  • vasodilation of arterioles and large coronary arteries
  • reduces coronary vascular resistance
  • stimulates guanylate cyclase to increase formation of cyclic GMP (cGMP)
  • cGMP activates protein kinase G (PKG), decreases Rho-kinase activity.
  • Reduced Rho-kinase activity permits an increase in myosin phosphatase activity, decreasing the Ca2+ sensitivity of the smooth muscle.[8]
21
Q

nifedipine found

A
  • inhibits the entry of Ca2+ ions by blocking these voltage-dependent L-type Ca2+ channels in vascular smooth muscle and myocardial cells.
  • ↓ intracellular Ca2+ ↓ peripheral arterial vascular resistance and dilatation of coronary arteries, leading to a ↓ in systemic blood pressure and ↑ myocardial oxygen delivery.
  • Nifedipine thus has hypotensive and antianginal properties.
  • antagonist of the mineralocorticoid receptor,
22
Q

Sodium Nitroprusside

A
  • prodrug
  • produce nitric oxide
  • NO triggers intracellular cGMP-mediated activation of PKG and then inactivation of myosin light chains, resulting in relaxation of VSM
  • ↓ in systemic vascular resistance (afterload), ventricular filling pressures, and systemic blood pressure with an ↑ in cardiac output.
23
Q

Sildenafil found

A
  • phosphodiesterase-5 inhibitor
  • mimics (cGMP).
  • accumulation of cGMP → to ↑ cGMP-dep PK activity, which phosphorylates multiple targets in SM cell.
  • The result of SM cell target protein phosphorylation is a ↓ in intracellular Ca2+, ↑ efflux of K, and deactivation of myosin light chain kinase, ultimately causing SM relaxation

accu bc of inhibition

24
Q

Glibenclamide

A
  • inhibiting the ATP-sensitive potassium channels (KATP) inhibitory regulatory subunit sulfonylurea receptor 1 (SUR1) in pancreatic beta cells.
  • This inhibition causes cell membrane depolarization, opening voltage-dependent Ca2+ Channels.[12]

Not a antihypertensive

Glyburide stimulates insulin secretion through the closure of ATP-sensitive potassium channels on beta cells, raising intracellular potassium and calcium ion concentrations

25
Q

ODQ found

A
  • soluble guanylyl cyclase (sGC, nitric oxide-activated enzyme) inhibitor.
    *
26
Q

Y-27632

A

ATP-competitive inhibitor of ROCK-I and ROCK-II

26
Q
A
27
Q

L-NAME

A

nonselective inhibitor of nitric oxide synthetases (NOS)

28
Q

Acetylcholine

A
  • decreases blood pressure by stimulating endothelium nitric oxide-dependent vasodilation in resistance arterioles
  • activates guanylate cyclase, increasing cyclic GMP levels, leading to relaxation of the smooth muscle and vasodilation.

Release NO

29
Q

Atropine

A
  • blocking muscarinic receptors
  • Increase heart rate
  • Reduce vasodilation