DRUG RECEPTORS

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DRUG RECEPTORS:

DRUG RECEPTORS M.KALAISELVI I-M.Tech

INTRODUCTION:

INTRODUCTION Drug Receptors: The component of a cell or organism that interacts with a drug and initiates the chain of events leading to the drug's observed effects. The ability to bind to a receptor is mediated by the chemical structure of the drug . Drug (D) + Target (R)↔ Drug-Target (DR) D + R ↔ DR K D = [D] x [R]/[DR ]

DRUG RECEPTOR INTERACTION:

DRUG RECEPTOR INTERACTION Drugs interact with receptor sites localized in macromolecules which have protein-like properties and specific three dimensional shapes. A minimum three point attachment of a drug to a receptor site is required. Receptors vary greatly in structure so a specific chemical structure is required for the receptor site and a complementary drug structure.

BASIC INTERACTIONS :

BASIC INTERACTIONS Hydrogen bonding Ionic interactions Covalent bonds Vander Waals forces Drugs that interact with receptors can be classified as being either agonists or antagonists .

AGONISTS:

AGONISTS A drug that activates or enhances cellular activity on binding. Effect of an agonist is proportional to the active drug- receptor complexes formed Examples: drugs that bind to beta receptors in the heart drugs that bind to alpha receptors on blood vessels Biochemicals that initiate these changes are referred to as second messengers .

Contd.. :

Contd..

ANTAGONISTS:

ANTAGONISTS Bind to the receptor but do not initiate a change in cellular function. Occupy the receptor and prevent the binding of agonists- antagonist. Antagonists are also referred to as blockers.

Contd..:

Contd.. Reversible antagonist (ex: propranolo l - adrenoceptor antagonist- heart) Irreversible antagonist (Phenoxybenzamine - hypertension) Irreversible receptor antagonists are chemically reactive compounds.

FACTORS GOVERNING DRUG ACTION:

FACTORS GOVERNING DRUG ACTION Two factors that determine the effect of a drug on physiologic processes are Affinity (Antagonists) Intrinsic activity(agonists )

RECEPTORS TYPE:

RECEPTORS TYPE G-protein coupled receptors Ligand gated ion channels Tyrosine kinase receptors Intracellular receptors

FOUR TYPES OF RECEPTORS:

FOUR TYPES OF RECEPTORS

G-PROTEIN COUPLED RECEPTORS:

G-PROTEIN COUPLED RECEPTORS

LIGAND GATED ION CHANNELS:

LIGAND GATED ION CHANNELS

Contd..:

Contd.. The direction of travel being determined by the concentration gradient. Example . Nicotinic acetylcholine receptors found at the neuromuscular junction

TYROSINE KINASE RECEPTORS:

TYROSINE KINASE RECEPTORS

Contd..:

Contd.. Receptors for insulin (tk receptor) Receptors that function as transmembrane enzymes Receptors for Cytokines ex: erythropoietin, somatotropin

INTRACELLULAR RECEPTORS:

INTRACELLULAR RECEPTORS

PowerPoint Presentation:

Lipid soluble ligands are able to cross the cell membrane and activate nuclear receptors which in turn alter DNA transcription. Steroid receptors are an example.

conclusion:

conclusion From this it can be concluded that the receptors play an important role in the drug distribution to the various target site. Different types of receptors are required for various drugs to make the effective drug distribution.

Thank you:

Thank you

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