Noradrenaline Synthesis, Release And Storage Flashcards
Where are cholesterol processing enzymes located in the cell
Smooth ER and inner mitochondrial membrane
Parenchyma cells can produce cholesterol de novo by Endocytosis of LDL, cholesterol rich lipid droplets in cytoplasm
Cells in the adrenal medulla are called
Pheochromocytes
In adrenal medulla how many % of E and NE are released
E- 80%
NE- 20%
How are epinephrine and norepinephrine released
Secreted into the blood by exocytosis of chromaffin granules
Volume of L-tyrosine in plasma
1-1.5mg/dl
Plasma ration of epinephrine and norepinephrine
NE-80%
E-20%
8:2
List the excitatory and inhibitory adrenergic receptors
Alpha1 and beta 1- excitatory
Alpha2 and beta2- inhibitory
Location of alpha 1 adrenergic receptors and examples of response elicited
Most sympathetic target cells
NE>E
Generalized arteriolar vasoconstriction
Location of alpha 2 adrenergic receptors and examples of response elicited
Digestive system
NE>E
Decreased motility in the digestive tract
Location of beta 1 adrenergic receptors and examples of response elicited
Heart
NE=E
Increased rate and strength of cardiac muscle contraction
Location of beta 2 adrenergic receptors and examples of response elicited
Skeletal muscle,smooth muscle of some blood vessels and organs
Breakdown of glycogen in skeletal muscle
Bronchiolar dilation and arteriolar vasodilation in skeletal muscles and heart
Cofactors of tyrosine hydroxylase
Fe2+
Tetrahydrobiopterin
Cofactors of L-aromatic amino acid decarboxylase
Pyridoxal phosphate
Where is dopa decarboxylase stored
Stored in secretory vesicles
Enter by active transport
VMAT- vesicular mono amine transporters
Cofactor of dopamine beta hydroxylase
Copper and vitamin C
Cofactor of PNMT
SAM- S-adenosylmethionine
Expression of PNMT depends on
Expression depends on high local cortisol from adrenal
Where are catecolamines stored
In secretory vesicles and they enter via VMAT transporter
PNMT is also found where in the body
Kidney, lungs, pancreas
Other things in secretory vesicles asides E and NE are chromogranins, dopamine Beta hydroxylase, ATP, other peptides
Catecholamines can reach most tissues except
Blood brain barrier
Fetus
T or F catecholamines are short lived molecules
T 10sec to 1.7 min
Catecholamines are how many percent associated with albumin
50-60% associated with albumin
Elimination of Catecholamines
Reuptake into nerve terminals
Reenter through VMAT
Cleaved by MAO mono amine oxidase in the nerve terminal
In target cells degraded by COMPT (catechol-o-methyl transferase)
5% directly filtered to urine
Where is Mao specifically found
Outer mitochondrial membrane of nerve
Mao also breaks down
Serotonin and histamine
Mao oxidized amino group to
Aldehyde
End product of MAO is
DOMA dihydroxymandelicacid
Two types of Mao
MAO-A for breakdown of E and NE
MAO-B: for breakdown of D,S,H
End product of COMT in breakdown of E and NE is
Metanephrine and normetanephrine
Normetanephrine can be further broken down into __________ by _______
VMA vanillymandelicacid
By mao
Normetanephrine and metanephrine can still be acted upon by the liver
Sulfated or glucoronidated
Inhibitors of tyrosine hydroxylase is
AMPT - alpha methyl para tyrosine
Inhibitor of dopamine beta hydroxylase is
Disulphiram
