Chapter 4 Flashcards
Adenylate Cyclase
An enzyme located on the inner surface of many cell membranes; it is important in mediating biochemical changes in the cell in response to drug and hormone stimulation (SYN: adenyl cyclase)
Affinity
The mutual attraction between a drug and a specific cellular receptor
Agonist
A drug that binds to a receptor and causes some change in cell function (ANT: antagonist)
Allosteric modulators
Substances that bind to a cell receptor and alter the receptor’s affinity for specific drugs; common allosteric modulators include guanine nucleotides, ammonium ions, calcium, and other divalent cations
Antagonist
A drug that binds to a receptor but does not cause a change in cell activity (SYN: blocker)
Cyclic Adenosine Monophosphate (cAMP)
The ring-shaped conformation of adenosine monophosphate, which is important in activ as a second messenger in mediating the intracellular response to drug stimulation
Desensitization
A brief and transient decrease in the responsiveness of cellular receptors to drug effects
Down-Regulation
A prolonged decrease in the number and/or sensitivity of drug receptors, usually occurring as a compensatory response to overstimulation of the receptor
Gamma-aminobutyric Acid (GABA)
An inhibitory neurotransmitter in the brain and spinal cord
G Proteins
Proteins that bind with guanine nucleotides and regulate cell activity. G proteins often serve as a link between surface receptors and ion channels or intracellular enzymes such as adenyl cyclase.
Second Messenger
The term applied to compounds formed within the cell, such as cyclic AMP. The second messenger initiates a series of biochemical changes within the cell following stimulation of a receptor on the cell’s outer surface by drugs, hormones, and so on.
Selective Estrogen Receptor Modulator (SERM)
A drug that activates estrogen receptors on bone and vascular tissues, while blocking estrogen receptors on breast and uterine tissues. These drugs can be used to enhance bone mineralization and to prevent certain cancers.
