1. About
Second messengers
Dr. Yasser Ashour
By
Dr.Darine Ashraf
Dr.Alaa Mamdouh

2. Second messengers are intracellular
signaling molecules released by the
cell to trigger physiological changes
such as proliferation, differentiation,
migration, survival, andapoptosis.
Secondary messengers are therefore
one of the initiating components of
intracellular signal
transduction cascades.

4. Examples of second messenger
molecules includecyclic AMP, cyclic
GMP, inositol
trisphosphate, diacylglycerol,
and calcium.
The cell releases second messenger
molecules in response to exposure to
extracellular signaling molecules—
the first messengers.

7. CAMP PATHWAY
Ligands : Epinephrine Ach
Primary Effector : Adenyl
cyclase
Secondary messenger : cAMP

9. CGMP PATHWAY
Ligands : ANP & NO
Primary Effector : Guanylate cyclase
Secondary messenger : cGMP

14. CALCIUM AS SECOND MESSENGER
Calcium ions – once they enter the cytoplasm exert allasteric
regulatory effects on many enzymes & protien .
Calcium acts as a second messenger by indirect signal
transduction pathways such as via G protein – coupled
receptors .

16. EICOSANOIDS
This class of llipids act as signaling molecules that binds to
cell surface molecules .
They include :
Prostaglandins
Prostacyclin
Thromboxanes
Leukotrienes

19. GENERAL SCHEMATIC OF SECOND MESSENGER
MECHANISM