Membrane transport of Na+ and K+

Question 1

Na+/K+

Answer 1

at least 2 subunit
4 alpha isoforms
and 3 beta isoforms

Question 2

FXYD MOTIF

Answer 2

1. N-terminal segment
2. phe-X-tyrosine-asoartate
3. regulates the transport kinetics of the alpha subunit
4. not present in all tissues
   role known in kidney and heart, pancreas and fetal liver as well
5. 7 isoforms

Question 3

OUABAIN-stranphantine or cardiac glycoside

Answer 3

medearte inhibion of sodium potassium ATPase

1. intracellular sodium increase so Ca++ Na+ exchabger pumps Na+ out and Ca++ in
2. synthesized in the zona glomerulosa from progesterone
   role: regulation of vascular tone
3. steroid structure
4. concentration in plasma 10-9mM

Question 4

alpha subunits location

Answer 4

alpha1: all tissues, only one in kidney medulla
alpha2: striatal smooth muscle, T tubules of cardiac muscle
alpha3: ovary, leukocytes, brain and heart
alpha4: testis

Question 5

VMAT

Answer 5

VMAT1: brain and neuroendocrine cells
VMAT2: neurons and adrenal chormaffi cells
VMAT3: Cholinergic neuros
inhibited by: H+ inophores