Modules 3 & 4: Key Terms

agonist: a drug that stimulates or promotes a receptor’s response; an agonist can cause a similar effect to the drug for which it serves as an agonist by replacing the drug in the neurotransmitter response system (being recognized by the binders)

anandamide: neurotransmitter responsible for relaxation and analgesia (pain reduction)

anhedonia: a person’s inability to experience feelings of pleasure in situations which are usually found to be enjoyable

antagonistic: a relationship between a drug and its specific receptors in the brain whereby the antagonist drug prevents or blocks the receptor response to another substance

dopamine: neurotransmitter involved in the reward and pleasure centers of the brain with a significant role in the development of substance use disorders involving many different drugs, as well as non-substance addiction; usually inhibitory

dysphoria: the experience of a profound sense of unease, unhappiness, and general dissatisfaction, often associated with major depression and anxiety.

endogenous: occurs naturally, internal to the body (compared to exogenous, introduced from outside the body)

endorphins: inhibitory neurotransmitter with an effect of blocking pain signals, similar to opioids; occurs naturally in the body (endogenous)

enkephalins: occurring naturally in the body (endogenous), bind to the body’s opioid receptors and act as a “natural” painkiller

epinephrine: a neurotransmitter that is usually excitatory, involved in the “fight or flight” response

excitatory: stimulating action

GABA: nickname for the inhibitory neurotransmitter gamma-aminobutyric acid that reduces nervous system excitability; alcohol mimics some effects of GABA by binding to GABA receptors and inhibiting neurons from passing signals

glutamate: excitatory neurotransmitter involved in cognition, memory, and learning; its release is suppressed by alcohol, which causes slower brain activity inhibitory: blocking or suppressing action

neurotransmitters: naturally occurring (endogenous) chemical messengers between neurons

norepinephrine: acts as a neurotransmitter playing a role in attention/arousal, emotion, sleep, dreaming, and learning (also called noradrenaline); part of the “fight or flight” response of the autonomic nervous system for calming after excitation

potentiation: an interaction between two substances that produces a combined effect greater than the sum of the individual responses.

presynaptic neuron: the neuron sending communication to a neighboring neuron by releasing neurotransmitters across the synapse (synaptic cleft) between them

postsynaptic neuron: the neuron receiving communication from a neighboring neuron by accepting the neurotransmitters released into the synapse (synaptic cleft) between them

serotonin: a neurotransmitter that is usually inhibitory and has an indirect effect by affecting the responses of neurons to other neurotransmitters like dopamine and norepinephrine (keeps them from overreacting); affected by many different drugs, playing a significant role in the brain’s reward systems, thus is involved in substance use disorders and addiction

synapse/synaptic cleft: the communication space between two neurons where released neurotransmitters are concentrated until received/retrieved

transporters: responsible for returning neurotransmitter chemical units back to the presynaptic neuron after they have been released into the synaptic cleft (reloading for next time)