Durgesh kushwaha

Drug-receptor interactions describe how drugs bind to receptors, influencing potency, efficacy, and selectivity. Drugs produce their effects mainly by interacting with receptors—specific macromolecules usually found on or within cells. Key Concepts of Drug-Receptor Interactions: Receptor: A protein molecule that receives chemical signals from outside a cell. Ligand: A molecule (e.g., drug) that binds to a … Read more

This article explains about the Signal transduction mechanisms explain how receptors convert external signals into cellular responses. Signal Transduction Mechanisms Signal transduction is the process by which a chemical signal (like a drug or hormone) is transmitted from the outside of the cell to the inside, leading to a cellular response. Most drugs act through … Read more

GPCRs are membrane receptors that transmit signals via G-proteins, regulating many physiological processes. Structure of GPCRs: Single polypeptide chain with 7 transmembrane α-helices Coupled to G-proteins (GTP-binding proteins) inside the cell Mechanism of GPCRs: Agonist binds to receptor (outside of cell) Receptor undergoes conformational change Activates G-protein by exchanging GDP for GTP G-protein dissociates into … Read more

This article explains about the Ligand-gated ion channels are receptors that open or close ion pathways in response to specific ligands. Structure of Ligand-gated ion channels: Multi-subunit protein with a central ion pore Opens or closes in response to ligand (drug/neurotransmitter) binding Mechanism: Ligand binds to receptor Ion channel opens Specific ions (Na⁺, K⁺, Ca²⁺, … Read more

Regulation of receptors involves upregulation or downregulation, affecting drug sensitivity and therapeutic response. Regulation of Receptors Cells dynamically regulate receptors in response to various stimuli to maintain homeostasis. Key mechanisms include: Receptors can change in number or sensitivity in response to drug exposure: Upregulation Increase in receptor number or sensitivity. Occurs after prolonged use of … Read more

Classification of receptors is based on structure, function, and response, including ion channel, GPCR, enzyme, and nuclear types. Classification of Receptors Receptors are classified based on their structure and signal transduction mechanism: Ionotropic Receptors (Ligand-Gated Ion Channels) Response in milliseconds. Example: Nicotinic acetylcholine receptor, GABA-A receptor. Metabotropic Receptors (G-Protein Coupled Receptors – GPCRs) Response in … Read more

Receptor theories explain how drugs produce effects by binding to receptors and activating or blocking them. Receptor Theories These theories explain how drugs interact with receptors and how this leads to a response: Historically, various theories have been proposed to explain how drugs interact with receptors and elicit responses: Occupancy Theory (Clark’s Theory) The intensity … Read more

Pharmacodynamics Pharmacodynamics refers to what the drug does to the body – including the biochemical and physiological effects of drugs and their mechanisms of action. Principles of Drug Action Stimulation Increases the activity of a specific organ or system. Example: Adrenaline stimulates β1-receptors to increase heart rate and contractility. Depression Decreases the activity of a … Read more

Absorption of Drugs refers to the process by which a drug enters the bloodstream from its site of administration. Factors Affecting Absorption: Route of Administration: Oral, IV, IM, subcutaneous, transdermal, inhalational, etc. IV route bypasses absorption as the drug is delivered directly into the bloodstream. Physicochemical Properties of the Drug: Solubility (lipid vs. water solubility) … Read more

Allergy (Drug Hypersensitivity) is an abnormal immune reaction to a drug, causing effects like rash, swelling, or anaphylaxis. Definition of Drug Hypersensitivity: A drug allergy is an immune system-mediated adverse drug reaction. It can occur at low doses, is unpredictable, and is not related to the pharmacologic action of the drug. Types of Hypersensitivity Reactions … Read more