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Flashcards in chapter 4: chemistry of behavior Deck (50):
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Exogenous

Arising from outside the body

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Endogenous

Produced inside the body

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Presynaptic

Located on the "transmitting" side of a synapse

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Synapse

The location at which information flows between a presynaptic neuron and a postsynaptic neuron, often through the conversion of electrical activity in the presynaptic neuron into a secretion of chemical neurotransmitter that alters the functioning of the postsynaptic neuron

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Exocytosis

A cellular process that results in the release of a substance into the extracellular space

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Neurotransmitter

A signaling chemical, released by a presynaptic neuron, that diffuses across the synaptic cleft to alter the functioning of the postsynaptic neuron

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Neurotransmitter receptor

A specialized protein that is embedded in the cell membrane, allowing it to selectively sense and react to molecules of the corresponding neurotransmitter

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Postsynaptic

Located on the "receiving" side of a synapse

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Reuptake

The reabsorption of molecules of neurotransmitter by the neurons that released them, thereby ending the signaling activity of the transmitter molecules

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Transporter

A specialized membrane component that returns transmitter molecules to the presynaptic neuron for reuse

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Ionotropic receptor

A receptor protein containing an ion channel that opens when the receptor is bound by an an agonist

Also called ligand-gated ion channel

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Metabotropic receptor

A receptor protein that does not contain ion channels but may, when activated, use a G protein system to open nearby ion channels or to produce other cellular effects

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Amine neurotransmitter

A neurotransmitter based on modifications of a single amino acid nucleus. Examples include acetylcholine, serotonin, and dopamine

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Amino acid neurotransmitter

A neurotransmitter that is itself an amino acid. Examples include GABA, glycine, and glutamate

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Peptide neurotransmitter

A neurotransmitter consisting of a short chain of amino acids

Also called neuropeptide

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Gas neurotransmitter

A neurotransmitter that is a soluble gas. Examples include nitric oxide and carbon monoxide

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Acetylcholine (ACh)

A neurotransmitter found in the autonomic nervous system, motor systems, and throughout the brain

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Cholinergic

Referring to cells that use acetylcholine as their synaptic transmitter

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Basal forebrain

A region, ventral to the basal ganglia, that is the major source of acetylcholine in the brain

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Dopamine (DA)

A monoamine transmitter found in the midbrain – especially the substantial nigra – and in the basal forebrain

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Dopaminergic

Referring to cells that use dopamine as their synaptic transmitter

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Substantia nigra

A brainstem structure that innervates the basal ganglia and is the source of all dopaminergic projections

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Ventral tegmental area (VTA)

A portion of the midbrain that projects dopaminergic fibers to the nucleus accumbens

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Serotonergic

Referring to cells that use serotonin as their synaptic transmitter

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Raphe nuclei

A string of nuclei in the midline of the midbrain and brainstem that contain most of the serotonergic neurons of the brain

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Serotonin (5-HT)

A synaptic transmitter that is produced in the raphe nuclei and is active in structures throughout the cerebral hemispheres

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Noradrenergic

Referring to cells using norepinephrine (noradrenaline) as a transmitter

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Norepinephrine (NE)

A neurotransmitter that is produced and released by sympathetic postganglionic neurons to accelerate organ activity. It is also produced in the brainstem and found in projections throughout the brain

Also called noradrenaline

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Locus coeruleus

A small nucleus in the brainstem whose neurons produce norepinephrine and modulate large areas of the forebrain

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Lateral tegmental area

A brainstem region that provide some of the norepinephrine-containing projections of the brain

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Glutamate

An amino acid transmitter, the most common excitatory transmitter

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Gamma-aminobutyric acid (GABA)

A widely distributed amino acid transmitter, and the main inhibitory transmitter in the mammalian nervous system

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Opioid peptides

A type of endogenous peptide that mimics the effects of morphine in binding to opioid receptors and producing marked analgesia and reward

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Retrograde transmitter

A neurotransmitter that diffuses from the postsynaptic neuron back to the presynaptic neuron

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Ligand

A substance that binds to receptor molecules, such as a neurotransmitter or drug that binds postsynaptic receptors

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Agonist

A molecule, usually a drug, that binds a receptor molecule and initiates a response like that of another molecule, usually a neurotransmitter

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Antagonist

A molecule, usually a drug, that interferes with or prevents the action of a neurotransmitter

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Binding affinity

The propensity of molecules of a drug (or other ligand) to bind to receptors

Also called affinity

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Efficacy or intrinsic activity

The extent to which a drug activates a response when it binds to a receptor

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Dose-response curve (DRC)

A formal graph of a drug's effects (on the y-axis) versus the dose given (on the x-axis)

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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

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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

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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

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Drug tolerance

A condition in which, with repeated exposure to a drug, an individual becomes less responsive to a constant dose

Also called tolerance

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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

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Functional tolerance

The form of drug tolerance that arises when repeated exposure to the drug causes receptors to be up-regulated or down-regulated

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Down-regulation

A compensatory decrease in receptor availability at the synapses of a neuron

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Up-regulation

A compensatory increase in receptor availability at the synapses of a neuron

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Cross-tolerance

A condition in which the development of tolerance for one drug causes an individual to develop tolerance for another drug

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Autoreceptors

A receptor for a synaptic transmitter that is located in the presynaptic membrane and tells the axon terminal how much transmitter has been released