In biochemistry, in the biological context of organisms ' regulation of gene expression and production of gene products, downregulation is the process by which a cell decreases the production and quantities of its cellular components, such as RNA and proteins, in response to an external stimulus.

Upregulation • Upregulation refers to an increase in the number of receptors due to prolonged deprivation of receptors of interacting with their physiological neurotransmitter (e.g. by denervation of chronic use of a receptor antagonist).

Jan 29, 2023 · Several issues in drug dosing can be explained in terms of Kd, receptor occupancy, and up/downregulation. Tolerance to a drug, where the effects seem to diminish with continued dosing, frequently occurs with prolonged dosing of opioids. Activation of opioid receptors stimulates the production of intracellular proteins called arrestins.

'Receptor upregulation' refers to the phenomenon where an increase in the number of receptors on a cell's surface occurs, often in response to prolonged exposure to specific substances or stimuli. You might find these chapters and articles relevant to this topic.

Receptor upregulation and downregulation affect adaptation to drugs (eg, desensitization, tachyphylaxis, tolerance, acquired resistance, postwithdrawal supersensitivity). Ligands bind to precise molecular regions, called recognition sites, on receptor macromolecules.

Up-regulation (or sensitization) refers to an increase in receptor density resulting from low levels of the endogenous ligand or chronic exposure to an antagonist, while down-regulation (or desensitization) denotes a decrease in receptor density with prolonged exposure to large amounts of ligand or persistent exposure to another agonist.

Abusive drugs, of all drugs studied, cause cell death and nerve fiber changes in the central nervous system. Downregulation and upregulation of MRI activities were seen in various parts of the brain in heroin and ketamine addicts.

This chapter will review the pharmacological characteristics of antagonist-induced opioid receptor upregulation, the accompanying functional super-sensitivity, and potential mechanisms involved. In addition, upregulation of opioid receptors following administration of …

Upregulation is the process by which a cell increases the number or sensitivity of receptors on its surface in response to various stimuli, often resulting in enhanced cellular responses to signaling molecules.

A rapid upregulation of β‐adrenergic receptors is characteristic of myocardial ischemia and hyperthyreosis. Blockade of β‐adrenergic receptors inhibits the basal receptor activity and action of endogenous catecholamine and may explain part …