Pharmacology and Neurotransmission: Receptor Actions, Depressants, Opioids, and Stimulants

Vocabulary flashcards reviewing neurochemical concepts, receptor classifications, depressants, opioids, and stimulants from the lecture.

G protein coupled receptor

A receptor that, upon binding a neurotransmitter, indirectly causes ion channels to open or close by releasing a G protein that transmits an internal signal.

Full agonist

A drug that binds directly to a receptor to fully open ion channels and fully activate the cell, producing the highest level of response.

Partial agonist

A drug that binds to a receptor and increases the likelihood of firing, but only achieves partial channel opening and activation compared to a full agonist.

Antagonist

A drug that binds to a receptor to block endogenous ligands from entering, maintaining neural firing at its natural baseline level without increasing or decreasing it.

Inverse agonist

A drug that binds to a receptor and actively slows down baseline neural activity, making the neuron significantly less likely to fire.

Endogenous ligand

A naturally occurring chemical or neurotransmitter within the body that binds to a receptor to activate or open it.

Depressants

A category of drugs that reduce activity in the central nervous system, producing sedative and hypnotic effects.

Sedative

A drug effect that reduces anxiety and lowers overall activity levels without necessarily putting a person to sleep.

Hypnotic

A drug property or effect characterized specifically by its ability to induce sleep.

Delirium tremens

A severe alcohol withdrawal syndrome appearing around 48 hours after cessation of long-term heavy drinking; symptoms include hallucinations, delusions, confusion, seizures, and a mortality rate of up to 25% without treatment.

Barbiturates

An older class of sedative depressants that selectively suppress activity in higher-order frontal cortical centers of the brain and carry a high overdose risk.

Benzodiazepines

Depressant drugs such as Valium and Xanax that replaced barbiturates to treat acute anxiety and panic attacks.

GABA

An inhibitory neurotransmitter whose receptor activity is enhanced by depressant drugs, leading to central nervous system suppression.

Chloride ion

A negatively charged ion that enters the neuron through activated GABA receptor channels, hyperpolarizing the cell and making action potentials harder to trigger.

Opiates

Hypnotic, euphoric, and analgesic drugs directly derived from the opium poppy native to Central Asia, including heroin and morphine.

Analgesic

A substance or medicinal property that relieves pain.

Euphoric

A characteristic of certain drugs, such as opioids, that induces intense feelings of pleasure.

Opioids

Synthetic or non-poppy-derived substances that mimic opiates by binding to endogenous opioid receptors to produce pain relief and euphoria (e.g., fentanyl, oxycontin, hydrocodone).

Endorphins

Naturally produced endogenous neurotransmitters in the body that bind to and activate opiate receptors.

Long term depression (in opioid action)

The reduced linkage and communication between presynaptic and postsynaptic neurons caused by opioids closing presynaptic calcium channels.

Substance P

A neurotransmitter in the somatosensory system involved in pain signaling whose pathway is inhibited by opioids.

Stimulants

A class of drugs that increase central nervous system activity, resulting in arousal, elevated mood, alertness, and increased energy.

Cocaine

A stimulant drug that inhibits the active reuptake of serotonin, dopamine, and noradrenaline into the presynaptic neuron, leaving more of these neurotransmitters active in the synapse.

Noradrenaline

The neurotransmitter counterpart to adrenaline that induces fight-or-flight effects such as a racing heart rate.

Methamphetamine

A stimulant that triggers an extreme dopamine reaction by simultaneously blocking dopamine reuptake channels and boosting its production and release.