L2-4 Psychoactive Drugs & Addiction

These flashcards provide terminology and definitions related to psychoactive drugs and addiction, aimed to facilitate understanding and retention of key concepts from the lecture.

CT (Computed Tomography)

An imaging technique used to create detailed images of internal structures, often used in diagnosing neuropsychiatric disorders.

MRI (Magnetic Resonance Imaging)

An imaging technique that uses magnetic fields and radio waves to produce detailed images of the body's tissues and structures.

fMRI (Functional Magnetic Resonance Imaging)

A type of MRI that measures brain activity by detecting changes associated with blood flow.

PET (Positron Emission Tomography)

An imaging technique that uses small amounts of radioactive material to identify active brain regions.

SPECT (Single Photon Emission Computed Tomography)

A nuclear medicine imaging technique that provides information about blood flow and metabolism of brain tissues.

Serotonin (5-HT)

A neurotransmitter that affects mood, anxiety, and cognition, and is commonly associated with feelings of well-being.

Psychotomimetic Drugs

Substances that can induce symptoms similar to psychosis, including altered perceptions and hallucinations.

Locus Coeruleus

• A small cluster of nuclei in the brainstem

• main source of noradrenaline in CNS

• involved in physiological responses to stress and panic, arousal and memory

Cocaine

A potent stimulant drug that can lead to increased levels of catecholamines in the synaptic space, contributing to addiction.

Amphetamines

Stimulant drugs that can increase dopamine levels and are often used to treat ADHD and narcolepsy.

Epigenetic Therapy

Treatments that aim to modify gene expression through external factors (diet, behaviour) without changing the DNA sequence, potentially useful in addiction treatment.

Neuroadaptive Changes

Alterations in the brain's structure and function that occur as a response to chronic drug use, contributing to addiction. eg. tolerance

Reward Pathway

A brain circuit that reinforces behaviors through the release of neurotransmitters like dopamine, often involved in addiction.

Longitudinal Studies

Research studies that follow the same subjects over a period of time to assess changes and long-term effects.

Genetic Analysis

The examination of genetic changes that may increase the risk of developing certain diseases or conditions.

ayahuasca active ingredient

harmaline

peyote active ingredient

mescaline

magic mushroom active ingredient

psilocybin → psilocyn

LSD

vasoconstricting agent by ergot alkaloids

acts as agonist of brain 5-HT receptors

LSD mechanism of action

in the brain: if receptor is activated → decreased level of 5-HT (negative feedback) ⇒ AGONIST/PARTIAL AGONIST

how LSD affects dorsal raphe neurons

LSD DECREASES firing rate of raphe neurons (5-HT1A receptors)

dorsal raphe

serotonergic neurons that send extensive projections to the forebrain

how LSD affects locus coeruleus

LSD INCREASES activity in locus coeruleus neurons

what layer of pyramidal neurons does LSD increase the activity of?

layer V

reinforcing system

involves dompaine axons in VTA of medial forebrain bundle with axons that project to nucleus accumbens in cortical forebrain

spiroperidol

• antipsychotic that blocks reinforcement system

• dopamine receptor antagonist

medial forebrain bundle

• A collection of axons that connect VTA in midbrain to NAC in forebrain cortex

• reinforcement system and reward pathways

includes:

• 5-HT axons from raphe neurons

• noradrenergic axons from locus coeruleus neurons

• dopaminergic axons from VTA

how does cocaine work

• blocks voltage-gated sodium channels

• binds to monoamine transporter on presynaptic terminal

• prevents recycling of catecholamines (dopamine)

• therefore increased levels of catecholamines in synaptic space

lisdexamfetamine

prodrug. blocks reuptake of dopamine and norepinephrine, increasing their release

Dorsal Raphe Nucleus vs Locus Coeruleus

DRN → serotonin

LC → noradrenaline

Alterations in the DRN are implicated in depression.