1. GPCR & LIGAND GATED ION CHANNEL
DR SATYABRATA SAHOO
3RD YEAR PGT
DEPT OF PHARMACOLOGY
SCB MCH CUTTACK
2. INTRODUCTION
RECEPTOR
• A Macromolecule or binding site located on the
surface or inside the effector cell that serves to
recognise the signal molecule or drug & initiate the
response to it,but itself has no other function.
• There are various types of receptors.
3.
4. GPCR
• A large superfamily of receptors having seven helical
membrane span serpentine like receptors with an
amine end and carboxyl end.
• Biogenic amines , Eicosanoids , other lipid signaling
molecules, peptides, opiods etc. Act through G
Protein coupled receptors.
• G Protein acts as coupling agent and activate various
enzymes like adenylyl cyclase, phospholipase c etc &
results in response.
• GPCRs are third largest family of genes in human.
5. Cont..
LIGAND GATED ION CHANNELS/RECEPTOR OPERATED CHANNEL
• Receptors for several neurotransmitters form agonist
regulated ion selective channels in the plasma
membrane.
• For example - nicotinic cholinergic receptors, GABA-A
Receptor, receptors for glutamate , aspartate, glycine
etc.
12. SECOND MESSANGERS ASSOCIATED WITH GPCR
A. Cyclic Adenosine Monophosphate (cAMP)
• Acting as an intracellular second messenger,
cAMP mediates hormonal responses like
conservation of water by the kidney , Ca 2+
homeostasis , and increased rate and contractile
force of heart.
• Production of adrenal and sex steroids ,
relaxation of smooth muscle, and many other
endocrine and neural processes.
• cAMP Degraded to 5′-AMP by several cyclic
nucleotide phosphodiesterases .
13.
14.
15. B. Phosphoinositides and Calcium
• Some of the hormones, neurotransmitters,
and growth factors that trigger this pathway
bind to receptors linked to G proteins.
• For example, lithium ion, used in treatment of
bipolar (manic-depressive) disorder, affects
the cellular metabolism of phosphoinositides .
