Psychopharmacology Review

A set of question-and-answer flashcards covering key concepts from the psychopharmacology lecture, including neurotransmitters, drug mechanisms, tolerance, addiction theories, and major drug classes.

What three characteristics define a drug?

It is an exogenous chemical, alters the function of certain cells, and is effective in relatively small doses.

What are psychoactive drugs?

Substances that act on the nervous system and influence experience and behavior.

Which neurotransmitter is the brain’s main inhibitory transmitter?

GABA (Gamma-Aminobutyric Acid).

Which neurotransmitter is the principal excitatory transmitter involved in learning and memory?

Glutamate.

Dopamine imbalance is linked to which two major disorders?

Parkinson’s disease and schizophrenia.

Name the two major dopamine pathways and their functions.

Mesolimbic (reward/motivation) and nigrostriatal (movement control).

Which neurotransmitter targeted by SSRIs regulates mood, sleep, and appetite?

Serotonin (5-HT).

Which neurotransmitter activates the sympathetic ‘fight-or-flight’ response?

Norepinephrine (NE).

List four common routes of drug administration.

Ingestion, inhalation, peripheral injection, and central injection.

Which route of administration delivers drugs most rapidly to the CNS?

Central injection (e.g., epidural, intracranial).

What physiological barrier must drugs cross to reach the brain?

The blood–brain barrier.

Define the term ligand.

Any substance that binds to a receptor.

When a drug activates its receptor, it is called a(n) .

Agonist.

A drug that binds to a receptor but blocks activation is called a(n) .

Antagonist.

Give an example of a receptor agonist for the nicotinic acetylcholine receptor.

Nicotine.

Which drugs block D2 dopamine receptors as antagonists?

First-generation antipsychotics (e.g., haloperidol).

How does cocaine act as a dopamine agonist?

It blocks the dopamine reuptake transporter, increasing dopamine in the synapse.

What graph shows the relationship between drug dose and effect?

The dose-response curve (DRC).

What is binding affinity?

A drug’s ability to bind to its site of action (receptor or transporter).

Define efficacy (intrinsic activity).

The ability of a bound ligand to activate or block its receptor.

What is meant by the therapeutic index?

The ratio/difference between a drug’s effective dose (ED50) and toxic/lethal dose (LD50).

Why are benzodiazepines safer than barbiturates?

They have a wider therapeutic index (larger gap between effective and lethal doses).

What is tolerance?

Decreased sensitivity to a drug after repeated exposure, requiring higher doses for the same effect.

A rightward shift in the DRC indicates what phenomenon?

Tolerance.

What is drug sensitization (inverse tolerance)?

An increased response to the same dose following repeated exposure.

Define cross tolerance.

Tolerance to one drug produces tolerance to another acting on the same receptors.

Differentiate metabolic versus functional tolerance.

Metabolic: body eliminates drug faster; Functional: changes in receptor number or sensitivity at the site of action.

What learning process makes overdoses more likely in new environments?

Conditioned drug tolerance (context-specific tolerance).

What diagnostic term does DSM-5 use for addiction?

Substance Use Disorder (SUD).

Name the four major theoretical models of addiction.

Moral, disease, physical dependence, and positive reward models.

Which neural pathway is central to the positive reward model of addiction?

The mesolimbic dopamine pathway (VTA → nucleus accumbens).

Which animal paradigm measures voluntary drug intake?

Self-administration lever pressing.

Which animal paradigm assesses preference for a drug-paired environment?

Conditioned place preference.

How do most addictive drugs influence dopamine?

They increase dopamine release in the nucleus accumbens.

Give three presynaptic processes drugs can alter.

Transmitter production, transmitter release, and transmitter clearance (reuptake or degradation).

Name two postsynaptic processes affected by drugs.

Direct receptor agonism/antagonism and regulation of receptor number or intracellular signaling pathways.

What drug class alters sensory perception with low addiction potential?

Hallucinogens (psychedelics).

Which receptor does LSD strongly activate?

Serotonin 5-HT2A receptors.

Which neurotransmitters are massively released by MDMA?

Serotonin, dopamine, and norepinephrine.

What social-bonding hormone is elevated by MDMA use?

Oxytocin.

Name the two primary cannabinoids in cannabis and their main effects.

THC (produces the ‘high’) and CBD (anxiolytic effects).

Identify the two main cannabinoid receptors.

CB1 (primarily brain) and CB2 (primarily peripheral).

Explain retrograde signaling in the endocannabinoid system.

Endocannabinoids made postsynaptically travel backward to presynaptic terminals to inhibit neurotransmitter release.

Why does THC increase hunger?

THC binds CB1 receptors, inhibiting GABA neurons in the hypothalamus and disinhibiting hunger signals.

Which receptor is blocked by caffeine to increase transmitter release?

Presynaptic adenosine receptors.

How does nicotine enhance reward signaling?

It activates nicotinic ACh receptors on VTA neurons, increasing dopamine release.

What is cocaine’s primary mechanism of action?

It blocks reuptake of dopamine and norepinephrine by inhibiting their transporters.

Alcohol acts on which two receptor systems?

GABA receptor agonist and glutamate receptor antagonist.

List two structural brain changes linked to chronic alcohol abuse.

Cortical atrophy and white-matter loss (also diencephalon and cerebellar damage).

How do first- and second-generation antipsychotics differ?

First-generation block D2 receptors (treat positive symptoms); second-generation affect D2 plus serotonin/glutamate systems (help negative symptoms too).

Which enzyme is inhibited by MAO inhibitors?

Monoamine oxidase.

What is the action of SSRIs?

They block the serotonin reuptake transporter, increasing synaptic serotonin levels.

Name two major classes of anxiolytics and their mechanisms.

Benzodiazepines (GABA_A receptor agonists) and SSRIs (increase serotonin).

Which midbrain region rich in μ-opioid receptors mediates analgesia?

The periaqueductal gray.

How do opiates produce euphoria in the reward pathway?

They disinhibit VTA dopamine neurons, increasing dopamine release in the nucleus accumbens.

What is naloxone and how does it reverse overdose?

An opioid receptor antagonist with high affinity that displaces opiates from receptors, blocking their effects.

Chronic opioid use leads to what type of tolerance?

Functional tolerance via receptor down-regulation and reduced endogenous opioid production.

Give an example of an endogenous opioid.

Endorphins (also enkephalins or dynorphins).

Why didn’t humans evolve opioid or cannabinoid receptors for drug use?

These receptors evolved for endogenous ligands; drugs hijack the existing systems.

What property of hallucinogens makes them promising for psychiatric therapy?

They can reopen critical periods of neural plasticity, aiding treatments for depression, OCD, and other disorders.