lecture 18]

Question 1

how does angiotensin 2 help regulate water and salt intake?

Answer 1

-AngII binds AT1 R in the SFO > increase thirst (SFO> SON/PVN and MPN)
- ang2 binds AT1 R in OVLT> increase salt app

Question 2

describe ang2 effects on the kidneys

Answer 2

• promote sodium retention (bind AT1 R in kidney> increased act of Na+/H+ exchanger (which is an antiporter that allow Na to enter cell from kidney tub while excreting H+)
• inhibit further release of renin (negative feedbck mec to control release of renin)

Question 3

describe ang2 effect on the vasculature

Answer 3

• binds AT1 R expressed in vascular SM > couples through Gq > activate IP3 > increase intracel cal > promotes contraction of SM lining blood ves

Question 4

describe how ang2 effect anterior pit

Answer 4

• increases ACTH release > ACTH binds MC2R in adrenal cortex > stim synthesis and release of glucocorticoids, Mineralocorticoids, and Adrenal androgens

Question 5

what is aldosterone and what does it release in response to and function

Answer 5

• a mineralocorticoid
  Release in response to: Hyponatremia. Hyperkalemia

Maintains blood volume and pressure by:
- Promotes sodium reabsorption from the kidneys
- Increases excretion of potassium
- Increases water reabsorption through osmosis

Question 6

describe aldosterone binding to R
Receptor name and the result

Answer 6

• binds corticosteroid R (T1 mineralocorticoid R expressed in cytoplasm of cells in late distal tub and collecting duct)
• binding > translocation of complex to nucleus > increase transcription of Na Ch (increase reuptake of Na from lumen to tubule) and Na/K ATPase (increase expression of Na pumps)

Question 7

how does aldosterone effect the CNS

Answer 7

• stimulate R of the NTS > salt appetite
• also synergizes with Ang2 to increase salt app

Question 8

how do we know we got enough salt?

Answer 8

• salt satiety mainly sense in periphery
• R in liver help inhibit salt app
• increase BV sensed by baroR inhibit salt app

Question 9

What are disease states with decreased activity of the aldosterone system and symptoms

Answer 9

• hypoaldosteronism: inability to produce sufficient quantities of aldosterone
• Classical pseudohypoaldosteronism: 1) Mutations in the MR can impair its activity
  2) Mutations in amiloride-sensitive Na+ channel

symptoms: Patients exhibit hypotension, hyperkalemia (due to decreased retention of Na+)

Question 10

What are disease states with increased activity of the aldosterone system and symptoms

Answer 10

• Primary aldosteronism: Increased production of aldosterone
• Pseudoaldosteronism: Mutations in amiloride-sensitive Na+ channel that interfere with its downregulation > Constitutively active

symptoms: Patients exhibit hypertension, hypokalemia (due to excessive retention of Na+ and H2O (by osmosis))