Cardiovascular system and antihypertensives Flashcards
(23 cards)
What are common cardiovascular disorders?
Hypertension
Hypotension
Angina pectoris
Atherosclerosis
Cardiac arrhythmia
How can cardiovascular diseases lead to serious events?
They increase risk for myocardial infarction (heart attack), stroke, vascular dementia, heart failure, and poor circulation
What are key risk factors for hypertension?
Smoking
Obestiy
Dietary habits
Diabetes
Lack of physical activity
How is hypertension clinically diagnosed?
Blood pressure > 140mmHg/90mmHg; pre-hypertensive intervention is often advised at lower pressures
How can blood pressure be reduced?
1 - Reducing blood volue (diuretics)
2 - Increasinf arterial diameter (vasodilators)
3 - Reducing heart rate and contraction force (beta-blockers)
What are beta-adrenoreceptors located?
On cardiac, intestinal, bronchial, and vascular smooth muscle cells
What is their role in SNS activation?
Noradrenaline (NA) binds β1-adrenoreceptors, increasing heart rate (chronotropic effect) and contraction force (inotropic effect)
How do beta-blockers work?
They competitively inhibit β1-adrenoreceptors, preventing NA activation and reducing heart rate/force
What are examples of beta-blockers?
Propranolol (1st gen, non-selective, blocks β1 and β2)
Atenolol (2nd gen, selective for β1)
Oxprenolol (non-selective, partial agonist)
What is a potential side effect of non-selective bera-blockers?
Bronochoconstriciotn, which can be severe in asthmatics
What is the mechanism of thiazide diuretics?
They inhibit sodium-chloride (NaCl) co-transporter in kidney distal tubules, preventinf salt reabsorption -> water retention and excretion -> reduced blood volume -> lower BP
What are side effects of thiazides?
Frequent urination
Erectile dysfunction
Increased cholesterol
Gout
Possible link to Tupe II diabetes
Whhy are thiazide diuretics still widely used?
Low cost
Effective at low dose
Synergistic in combination with other drugs
What does the renin-angiotensin system regulate?
Vascular growth
Salt retention
Vasoconstriction
How does angiotensisn II affect blood vessels?
It binds AT1 receptors )Gq-linked GPCRs) on vascular smooth muscle, triggering phospholipase C activation -> Intracellular calcium release -> vasoconstriction
How do ACE inhibitors work?
They block ACE, preventing conversion of angiotensin I to angiotensin II
Leads to vasodilation, lower BP, reduced cardiovascular strain
What is an example of an ACE inhibitor?
Captopril (prototype drug)
Why do some ACE inhibitors cause coughing?
Bradykinin accumulation in bronchial tissue, triggering cough reflex
What is an alternative to ACE inhibitors?
AT1 receptor antagonists (e.g., Losartan) - they prevent angiotensis II binding, avoiding bradykinin accumulation
What is ACE2’s role beyond cardiovascular function?
Converts angiotensin II to angiotensin 1-7 (vasodilator peptide)
How does SARS-CoV-2 (COVID-19) interact with ACE2?
Spike protein binds to ACE2, allowing viral entry into host cells
S1 subunit - Bind ACE2
S2 subunit - Mediates membrane fusion
How do calcium antagonists work?
Block L-type calcium ion channels, preventinf calcium influx into cardiac and vascular smooth muscle cells -> reduced contraction force
What are examples of calcium antagonists?
Verapamil - Cardio-selective (treats cardiac arrhythmia)
Nifedipine - Coronary artery-specific (angina treatment)
Amlodipine - Smooth muscle slecetive (hypertension treatment )
