Chapter 4 Flashcards

Δ9-tetrahydrocannabinol (THC)
The major active ingredient in marijuana.
acetylcholine (ACh)
A neurotransmitter produced and released by parasympathetic postganglionic neurons, by motoneurons, and by neurons throughout the brain.
adenosine
In the context of neural transmission, a neuromodulator that alters synaptic activity. Adenosine receptors are the site of action of caffeine.
agonist
1. A molecule, usually a drug, that binds a receptor molecule and initiates a response like that of another molecule, usually a neurotransmitter. Compare antagonist (definition 1). 2. A muscle that moves a body part in the same general way as the muscle of interest; a synergistic muscle. Compare antagonist (definition 2). See also synergist.
allopregnanolone
A naturally occurring steroid that modulates GABA receptor activity in much the same way that benzodiazepine anxiolytics do.
amine neurotransmitter
A neurotransmitter based on modifications of a single amino acid nucleus. Examples include acetylcholine, serotonin, or dopamine.
amino acid neurotransmitter
A neurotransmitter that is itself an amino acid. Examples include GABA, glycine, or glutamate.
amphetamine
A molecule that resembles the structure of the catecholamine transmitters and enhances their activity.
analgesic
Referring to painkilling properties.
anandamide
An endogenous substance that binds the cannabinoid receptor molecule.
antagonist
1. A molecule, usually a drug, that interferes with or prevents the action of a transmitter. Compare agonist (definition 1). 2. A muscle that counteracts the effect of another muscle. Compare agonist (definition 2) and synergist.
antidepressants
A class of drugs that relieve the symptoms of depression. Major categories include monoamine oxidase inhibitors, tricyclics, and selective serotonin reuptake inhibitors.
antipsychotics
Also called neuroleptics. A class of drugs that alleviates schizophrenia.
anxiolytics
A class of substances that are used to combat anxiety. Examples include alcohol, opiates, barbiturates, and the benzodiazepines.
aspartate
An amino acid transmitter that is excitatory at many synapses.
atypical neuroleptics
A class of antischizophrenic drugs that have actions other than the dopamine D2 receptor antagonism that characterizes the typical neuroleptics. Atypical neuroleptics often feature selective and high-affinity antagonism of serotonin 5HT2 receptors.
autoreceptor
A receptor for a synaptic transmitter that is located in the presynaptic membrane telling the axon terminal how much transmitter has been released.
barbiturate
A powerful sedative anxiolytic derived from barbituric acid, with dangerous addiction and overdose potential.
benzodiazepine agonists
A class of anti-anxiety drugs that bind to sites on GABAA receptors.
binding affinity
Also called simply affinity. The propensity of molecules of a drug (or other ligand) to bind to their corresponding receptors. Drugs with high affinity for their receptors are effective even at low doses.
bioavailable
Referring to a substance, usually a drug, that is present in the body in a form that is able to interact with physiological mechanisms.
biotransformation
The process in which enzymes convert a drug into a metabolite that is itself active, possibly in ways that are substantially different from the actions of the original substance.
blockers.
#N/A
blood-brain barrier
The mechanisms that make the movement of substances from blood vessels into brain cells more difficult than exchanges in other body organs, thus affording the brain greater protection from exposure to some substances found in the blood.
caffeine
A stimulant compound found in coffee, cacao, and other plants.
catecholamines
A class of monoamines that serve as neurotransmitters, including dopamine and norepinephrine. See Table 4.1.
cholinergic
Referring to cells that use acetylcholine as their synaptic transmitter.
co-localization
Also called co-release. Here, the appearance of more than one neurotransmitter in a given presynaptic terminal.
cocaine
A drug of abuse, derived from the coca plant, that acts by potentiating catecholamine stimulation.
competitive ligand
A substance that directly competes with the endogenous ligand for binding to a receptor molecule. See Figure 4.2. Compare noncompetitive ligand.
cross-tolerance
A condition in which the development of tolerance for an administered drug causes an individual to develop tolerance for another drug.
cue-induced drug use
An increased likelihood to use a drug (especially an addictive drug) because of the presence of environmental stimuli that were present during previous use of the same drug.
degradation
The chemical breakdown of a neurotransmitter into inactive metabolites.
dependence
Also called addiction. In the context of substance-related disorders, the strong desire to self-administer a drug of abuse.
depressants
A class of drugs that act to reduce neural activity.
dissociative drug
A type of drug that produces a dreamlike state in which consciousness is partly separated from sensory inputs.
dopamine (DA)
A monoamine transmitter found in the midbrain—especially the substantia nigra—and basal forebrain. See Table 4.1; Figure 4.4.
dose-response curve (DRC)
A formal plot of a drug’s effects (on the y-axis) versus the dose given (on the x-axis). Analysis of dose-response curves can provide a range of information about the drug, such as its efficacy, potency, and safety. See Figure 4.8.
down-regulation
A compensatory reduction in receptor availability at the synapses of a neuron. Compare up-regulation.
dual dependence
Dependence for emergent drug effects that occur only when two drugs are taken simultaneously.
dynorphins
One of three kinds of endogenous opioids. Enkephalins and endorphins are the other two. See Table 4.1.
dysphoria
Unpleasant feelings; the opposite of euphoria.
efficacy
Also called intrinsic activity. The extent to which a drug activates a response when it binds to a receptor. Receptor antagonist drugs have low efficacy; receptor agonists have high efficacy. See Figure 4.8.
endocannabinoid
An endogenous ligand of cannabinoid receptors; thus, an analog of marijuana that is produced by the brain.
endogenous
Produced inside the body. Compare exogenous.
endogenous opioids
A family of peptide transmitters that have been called the body’s own narcotics. The three kinds are enkephalins, endorphins, and dynorphins. See Table 4.1.
endorphins
One of three kinds of endogenous opioids. Enkephalins and dynorphins are the other two. See Table 4.1.
enkephalins
One of three kinds of endogenous opioids. Endorphins and dynorphins are the other two. See Table 4.1.
excitotoxicity
The property by which neurons die when overstimulated, as with large amounts of glutamate.
exogenous
Arising from outside the body. Compare endogenous.
fetal alcohol syndrome (FAS)
A disorder, including intellectual disability and characteristic facial anomalies, that affects children exposed to too much alcohol (through maternal ingestion) during fetal development.
functional tolerance
Decreased responding to a drug after repeated exposures, generally as a consequence of up- or down-regulation of receptors.
gamma-aminobutyric acid (GABA)
A widely distributed amino acid transmitter, and the main inhibitory transmitter in the mammalian nervous system. See Table 4.1.
gas neurotransmitter
A soluble gas, such as nitric oxide or carbon monoxide, that is produced and released by a neuron to alter the functioning of another neuron. Usually gas neurotransmitters act in a retrograde fashion on presynaptic neurons.
glutamate
An amino acid transmitter, the most common excitatory transmitter. See Table 4.1.
glutamatergic
Referring to cells that use glutamate as their synaptic transmitter.
glycine
An amino acid transmitter, often inhibitory. See Table 4.1.
hallucinogens
A class of drugs that alter sensory perception and produce peculiar experiences.
heroin
Diacetylmorphine; an artificially modified, very potent form of morphine.
indoleamines
A class of monoamines that serve as neurotransmitters, including serotonin and melatonin. See Table 4.1.
insula
A region of cortex lying below the surface, within the lateral sulcus, of the frontal, temporal, and parietal lobes.
inverse agonist
A substance that binds to a receptor and causes it to do the opposite of what the naturally occurring transmitter does.
ionotropic receptor
A receptor protein that includes an ion channel that is opened when the receptor is bound by an agonist. See Figures 3.15, 4.1. See also ligand-gated ion channel. Compare metabotropic receptor.
ketamine
A dissociative anesthetic drug, similar to PCP, that acts as an NMDA receptor antagonist.
khat
Also spelled qat. An African shrub that, when chewed, acts as a stimulant.
ligand
A substance that binds to receptor molecules, such as those at the surface of the cell.
local anesthetic
A drug, such as procaine or lidocaine, that blocks sodium channels to stop neural transmission in pain fibers.
locus coeruleus
Literally, “blue spot.” A small nucleus in the brainstem whose neurons produce norepinephrine and modulate large areas of the forebrain.
LSD
Also called acid. Lysergic acid diethylamide, a hallucinogenic drug.
marijuana
A dried preparation of the Cannabis sativa plant, usually smoked to obtain THC.
Also called Ecstasy. A drug of abuse, 3,4-methylene-
mesolimbocortical pathway
A set of dopaminergic axons arising in the midbrain and innervating the limbic system and cortex. See Figure 4.4. Compare mesostriatal pathway.
mesostriatal pathway
A set of dopaminergic axons arising from the midbrain and innervating the basal ganglia, including those from the substantia nigra to the striatum. See Figure 4.4. Compare mesolimbocortical pathway.
metabolic tolerance
The form of drug tolerance that arises when repeated exposure to the drug causes the metabolic machinery of the body to become more efficient at clearing the drug.
metabotropic receptor
A receptor protein that does not contain an ion channel but may, when activated, use a G protein system to open a nearby ion channel. See Figures 3.13, 4.1. Compare ionotropic receptor.
modulatory site
A portion of a receptor that, when bound by a compound, alters the receptor’s response to its transmitter.
monoamine oxidase (MAO)
An enzyme that breaks down and thereby inactivates monoamine transmitters.
morphine
An opiate compound derived from the poppy flower.
muscarinic
Referring to cholinergic receptors that respond to the chemical muscarine as well as to acetylcholine. Muscarinic receptors mediate chiefly the inhibitory activities of acetylcholine. Compare nicotinic.
neurochemistry
The branch of neuroscience concerned with the fundamental chemical composition and processes of the nervous system.
neuroleptics
Also called antipsychotics. A class of drugs that alleviates symptoms of schizophrenia, typically by blocking dopamine receptors.
neuromodulator
See noncompetitive ligand.
neuropharmacology
Also called psychopharmacology. The scientific field concerned with the discovery and study of compounds that selectively affect the functioning of the nervous system.
neurosteroids
Steroids produced in the brain.
nicotine
A compound found in plants, including tobacco, that acts as an agonist on a large class of cholinergic receptors.
nicotinic
Referring to cholinergic receptors that respond to nicotine as well as to acetylcholine. Nicotinic receptors mediate chiefly the excitatory activities of acetylcholine, including at the neuromuscular junction. Compare muscarinic.
nitric oxide (NO)
A soluble gas that serves as a retrograde gas neurotransmitter in the nervous system.
noncompetitive ligand
Also called neuromodulator. A substance that alters the response to an endogenous ligand without interacting with that endogenous ligand’s recognition site. See Figure 4.2. Compare competitive ligand.
noradrenergic
Referring to systems using norepinephrine (noradrenaline) as a transmitter. See Figure 4.5.
norepinephrine (NE)
Also called noradrenaline. 1. A neurotransmitter produced and released by sympathetic postganglionic neurons to accelerate organ activity. Also produced in the brainstem and found in projections throughout the brain. See Table 4.1. 2. Also called noradrenaline. Here, a hormone secreted by the adrenal medulla under the control of the sympathetic nervous system, which prepares the body for action.
nucleus accumbens
A region of the forebrain that receives dopaminergic innervation from the ventral tegmental area. Dopamine release in this region may mediate the reinforcing qualities of many activities, including drug abuse.
opioid peptide
A type of endogenous peptide that mimics the effects of morphine in binding to opioid receptors and producing marked analgesia and reward. See Table 4.1.
opioid receptor
A receptor that responds to endogenous and/or exogenous opioids.
opium
A heterogeneous extract of the seedpod juice of the opium poppy,Papaver somniferum.
orphan receptor
Any receptor for which no endogenous ligand has yet been discovered.
partial agonist
A drug that, when bound to a receptor, has less effect than the endogenous ligand would. The term partial antagonist is equivalent. See Figure 4.8.
peptide neurotransmitter
Also called neuropeptide. A neurotransmitter consisting of a short chain of amino acids. See Table 4.1.
periaqueductal gray
The neuronal body–rich region of the midbrain surrounding the cerebral aqueduct that connects the third and fourth ventricles; involved in pain perception.
pharmacodynamics
Collective name for the factors that affect the relationship between a drug and its target receptors, such as affinity and efficacy.
pharmacokinetics
Collective name for all the factors that affect the movement of a drug into, through, and out of the body.
phencyclidine (PCP)
Also called angel dust. An anesthetic agent that is also a psychedelic drug. PCP makes many people feel dissociated from themselves and their environment.
raphe nuclei
A string of nuclei in the midline of the midbrain and brainstem that contain most of the serotonergic neurons of the brain.
receptor
1. The initial element in a sensory system, responsible for stimulus transduction. Examples include the hair cells in the cochlea, and the rods and cones in the retina. 2. Also called receptor molecule. A protein that binds and reacts to molecules of a neurotransmitter or hormone.
receptor subtype
Any type of receptor having functional characteristics that distinguish it from other types of receptors for the same neurotransmitter. For example, at least 15 different subtypes of receptor molecules respond to serotonin.
retrograde transmitter
A neurotransmitter that diffuses from the postsynaptic neuron back to the presynaptic neuron.
selective serotonin reuptake inhibitor (SSRI)
A drug that blocks the reuptake of transmitter at serotonergic synapses; commonly used to treat depression.
sensitization
1. A form of nonassociative learning in which an organism becomes more responsive to most stimuli after being exposed to unusually strong or painful stimulation. Compare habituation. 2. A process in which the body shows an enhanced response to a given drug after repeated doses. Compare tolerance.
serotonergic
Referring to neurons that use serotonin as their synaptic transmitter. See Figure 4.6.
serotonin (5-HT)
A synaptic transmitter that is produced in the raphe nuclei and is active in structures throughout the cerebral hemispheres. See Table 4.1; Figure 4.6.
striatum
The caudate nucleus and putamen together.
substance abuse
A maladaptive pattern of substance use that has lasted more than a month but does not fully meet the criteria for dependence.
substantia nigra
Literally, “black spot.” A group of pigmented neurons in the midbrain that provides dopaminergic projections to areas of the forebrain, especially the basal ganglia.
tolerance
A condition in which, with repeated exposure to a drug, an individual becomes less responsive to a constant dose. Compare sensitization (definition 2).
transmitter reuptake
The reabsorption of synaptic transmitter by the axon terminal from which it was released.
transporters
Specialized receptors in the presynaptic membrane that recognize transmitter molecules and return them to the presynaptic neuron for reuse.
tricyclic antidepressants
A class of drugs that act by increasing the synaptic accumulation of serotonin and norepinephrine.
typical neuroleptics
A major class of antischizophrenic drugs that share antagonist activity at dopamine D2 receptors. Compare atypical neuroleptics.
up-regulation
A compensatory increase in receptor availability at the synapses of a neuron. Compare down-regulation.
vaccination
Injection of a foreign substance, such as deactiveated viruses or conjugated molecules of drugs of abuse like cocaine, in order to provoke the production of antibodies against the foreign substance.
ventral tegmental area (VTA)
A portion of the midbrain that projects dopaminergic fibers to the nucleus accumbens.
withdrawal symptom An uncomfortable symptom that arises when a person stops taking a drug that he or she has used frequently, especially at high doses.
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