Download - RECEPTORS.ppt
RECEPTOR:
RECEPTORSIt is a specific binding site on the cell which exhibits some functional groups which trigger the pharmacological action
RECEPTORS
AFFINITY: Ability of agent to combine with receptor
INTRINSIC ACTIVITY: Ability of agent to activate the receptor (efficacy)
AGONIST: maximum affinity and efficacy
ANTAGONIST: having affinity but no efficacy
INVERSE AGONIST: having affinity and negative efficacy
Types of receptors: Iono tropic receptors G-protein coupled receptors Enzymatic receptors Nuclear receptors
RECEPTORS
Second messengers:
RECEPTORS
cAMP system
Phosphoinositol system
Arachidonic acid system
cGMP system
Tyrosine kinase system
receptor α2,β1,β2M2
α1M1,M3
Histamine - -
Transducer Gs(β1,β2)Gi(α2, M2)
Gq Unknown G-protein
- -
Primary effector
AC Phospholipase C
Phospholipase A
Guanylate cyclase
Tyrosine kinase
Secondary messenger
cAMP IP3,DAG Arachidonic acid
cGMP Protein phosphatase
Secondary effector
Protein kinase A
Ca++ release 5-lipoxygenase Protein kinase G
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RECEPTORSExamples of G-protein receptors:
Muscarnic receptors (cholinergic) Adrenergic receptors (α,β) Histamine receptors Dopamine receptors Opiate receptors Serotonin receptors (all except 5-HT3) GABAB receptors
RECEPTORSExamples of nuclear receptors:
Glucocorticoid receptors Minero corticoid receptors Oestrogen receptors Progestero receptors Androgen receptors Vit A and vit B receptors Thyroid hormone receptors
RECEPTORSOther receptors:
Spare receptors: Maximum response is observed even though when all the receptors of tissues are not occupied by drug moiety
Orphan receptors: Receptors with no endogenous ligand Eg: PPAR-α receptors (peroxysomal proliferated activated receptors)
Silent receptors: Biologically silent even though stimulations of receptors taking place no biological response
Normal receptors: Response observed when all the receptors of the tissue occupied by drug moiety
RECEPTORSREFERENCE:
Pharmacology by RANG and DALE Integrated pharmacology by WALKER pharmacology by LIPPINCOTT pharmacology by BERTRUM www.wikkipedia.org www.winona.edu www.pharmacologycorner.com www.psychopharmacologyinstitute.com