Vasoactive Peptides Flashcards
angiotensin II, vasopressin, endothelins, and neuropeptide Y are _________
vasoconstrictors
bradykinins, natriuretic peptides, vasoactive intestinal peptide, substance P, neurotensin, and calcitonin gene related peptide are __________
vasodilators
_______ cells are the site of synthesis, storage, and release of renin, location of macula densa beside renin secreting JG cells in afferent arteriole
granular
- increased NaCl flux through chemoreceptors in macula densa
- elevated BP through baroreceptors in afferent arteriole wall
- beta blockade by inhibiting sympathetic stimulation
- negative feedback by angiotensin II
all inhibit renin secretion
angiotensin will ______ peripheral resistance to increase afterload, ______ aldosterone secretion to increase preload
increase
increase
ACE inhibitors _______ both preload and afterload
decrease
only active ACE inhibitor?
captopril
- reduce angiotensin vasoconstriction with little reflex tachy
- decrease aldosterone release from adrenal medulla
- reduce destruction of bradykinin - enhance BP lowering, cause cough and angioedema
- renal renin secretion may increase b/c of reduction in negative feedback by AngII
ACE inhibitors
- adverse:
- dry, hacking, nonproductive cough
- angioedema, anaphylaxis
- hyperkalemia (due to inhibited aldosterone secretion)
- contraindicated in last 2 trimesters of pregnancy
ACE inhibitors
- receptors predominate in vascular smooth muscle and cause the known actions of Ang2
- selective for AT1
- may cause hyperkalemia
- do not affect bradykinin metabolism
- sartans
angiotensin receptor antagonists
- reduction in plasma renin activity
- reduce BP
renin inhibitor (aliskiren)
- potent arteriodilators formed by kallikreins
- produce pain, swelling, redness
kinins
- synthesized in hypothalamus together with oxytocin, secreted from posterior pituitary
- produce antidiuretic and vasopressor effects, (V1-vasoconstriction, V2-antidiuresis)
vasopressin (ADH)
- long acting analog with minimal V1 activity
- promotes antidiuresis, deficiency results in diabetes insipidus
desmopressin
- drug with both V1a and V2 antagonist effects
- approved for treatment of hyponatremia
conivaptan