chapter 1 vocab Flashcards
absorption
Movement of a drug from the site of administration to the circulatory system.
acute tolerance
Rapid tolerance formed during a single administration of a drug, as is the case with alcohol.
additive effects
Drug interactions characterized by the collective sum of the two individual drug effects.
affinity
Attraction between a molecule and a receptor.
area postrema
Area in the medulla of the brain stem that is not isolated from chemicals in the blood. It is responsible for inducing a vomiting response when a toxic substance is present in the blood.
astrocytes
Star-shaped cells of the nerve tissue that have numerous extensions and that modulate the chemical environment around neurons, metabolically assist neurons, and provide phagocytosis for cellular debris.
behavioral tolerance
The reduced effectiveness of a drug administered chronically that involves learning: either instrumental or classical conditioning.
bioavailability
Concentration of drug present in the blood that is free to bind to specific target sites.
biotransformation
Inactivation of a drug through a chemical change, usually by metabolic processes in the liver.
cerebrospinal fluid (CSF)
Fluid that surrounds the brain and spinal cord, providing cushioning that protects against trauma.
classical conditioning
Repeated pairing of a neutral stimulus with an unconditioned stimulus. Eventually the neutral stimulus becomes a conditioned stimulus and elicits a (conditioned) response that is similar to the original unconditioned response.
competitive antagonist
Drug that binds to a receptor but has little or no efficacy. When it competes with an agonist for receptor sites, it reduces the effect of the agonist.
concentration gradient
Difference in the amount or concentration of a substance on each side of a biological barrier, such as the cell membrane.
cross-tolerance
Tolerance to a specific drug can reduce the effectiveness of a another drug in the same class.
cytochrome P450 (CYP450)
Class of liver enzymes, in the microsomal enzyme group, responsible for both phase 1 and phase 2 biotransformation of psychoactive drugs.
depot binding
Type of drug interaction involving binding to an inactive site, such as to proteins in the plasma, to bone, or to fat.
dose-response curve
Graph used to display the amount of biological change in relation to a given drug dose.
double-blind experiment
Type of experiment in which neither the patient nor the observer knows the treatment received by the patient.
down-regulation
Decrease in the number of receptors, which may be a consequence of chronic agonist treatment.
drug action
Molecular changes associated with a drug binding to a particular target site or receptor.
drug competition
Interaction between two drugs that share a metabolic system and compete for the same metabolic enzymes. Bioavailability of one or both increases.
drug depots
Inactive sites where drugs accumulate. There is no biological effect from drugs binding at these sites, nor can they be metabolized.
drug disposition tolerance
metabolic tolerance
drug effects
Alterations in physiological or psychological functions associated with a specific drug.
efficacy
The extent to which a ligand-receptor binding initiates a biological action (e.g., the ability of an agonist to activate its receptor).
enteral
Drug administration by oral or rectal routes.
enzyme induction
Increase in liver drug-metabolizing enzymes associated with repeated drug use.
enzyme inhibition
Reduction in liver enzyme activity associated with a specific drug.
epidural
Method that involves administration of a drug into the cerebrospinal fluid surrounding the spinal cord.
fenestrations
Large pores in endothelial cells allowing rapid exchange between blood vessels and tissue
first-order kinetics
Term used to describe exponential elimination of drugs from the bloodstream.
first-pass metabolism
Phenomenon in which the liver metabolizes some of a drug before it can circulate through the body, particularly when the drug has been taken orally
gene therapy
Application of DNA that encodes a specific protein to increase or block expression of the gene product to correct a clinical condition.
genetic polymorphisms
Genetic variations in a population resulting in multiple forms of a particular protein
half-life
Time required to remove half of the drug from the blood. It is referred to as t1/2.
infusion pump
Drug delivery via an implanted pump (e.g., subcutaneous) that delivers regular, constant doses to the body or into the cerebral ventricles.
inhalation
Method that involves administration of a drug through the lungs.
intercellular clefts
Small gaps between adjacent cells.