effects of norepinephrine and epinephrine on cardiomyocyte
Post on 03-Jul-2015
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Submitted by:
Aldrin J. Corañez
4BIO4
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2. The G protein α subunit
activates adenylate cyclase.
Epinephrine/
norepinephrine
receptor
Epinephrine or
Norepinephrine
molecules
Adenylate
cyclase
G
Protein
Inactive
protein
kinase
Active
protein
kinase
Ca2+
ATPase
cAMP
Ca2+
ions
1. Binding of norepinephrine
or epinephrine changes the
shape of the β1 adrenergic
receptor, which activates the
associated G protein.
3. Adenylate cyclase
catalyzes the conversion
of ATP to cAMP.
4. The cAMP activates
protein kinase A.
5. The protein kinase
phosphorylates L-type Ca2+
channels, allowing Ca2+ to
enter the cell, which
stimulates contraction.
6. The protein kinase
phosphorylates Ca2+ channels
on the sarcoplasmic
reticulum, allowing Ca2+ to
move to the cytoplasm, which
stimulates contraction.
7. The protein kinase
phosphorylates myosin,
stimulating contraction.
8. The protein kinase
phosporylates the
sarcoplasmic Ca2+ ATPase,
speeding the removal of Ca2+
from the cytoplasm during
relaxation, which decreases
relaxation time.
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