Human Psychopharmacology - Flashcards

Flashcards generated from lecture notes on Human Psychopharmacology covering basic concepts, neurotransmitters, receptors, drug actions, and specific neurotransmitter systems like Glutamate, GABA, Dopamine, Noradrenaline, and Serotonin. Also covers addiction, mood disorders, and the role of peptides, lipids, nucleosides and gases.

Neurons

Basic building blocks of the nervous system; at rest have a negative charge. An action potential is triggered when the charge becomes sufficiently positive. Signals are received by dendrites and travel down the axon to the next neuron.

Myelin Sheath

Structure made of oligodendrocytes (glial cells, basically fat) wrapped around axons to speed up electrical conduction of the electrical impulse, due to saltatory conduction at Nodes of Ranvier.

Nodes of Ranvier

Gaps in the myelin sheath where depolarization happens during saltatory conduction.

Ion Channels

Act like a 'gate' for ions; neurotransmitter binding causes the gate to open allowing ions to flow through. Selective channels only allow one or a few types of ions to pass through.

G-Protein Coupled Receptors

Protein structures comprising of seven transmembrane units. They work through second messengers; neurotransmitter binding activates a second messenger system that can open a channel or cause other changes within the cell.

Neurotransmission

A chemical substance released from a neuron at a synapse, affecting postsynaptic neurons, muscle cells, or other effector cells. Can be excitatory or inhibitory, enabling rapid, precise communication.

Neuromodulation

A chemical substance released from a neuron that affects groups of neurons or effector cells, often through second messengers, producing long-lasting effects. Alters the subsequent responsiveness of neurons.

Drug Action at the Receptor

Drugs that act by 'mimicking' natural neurotransmitters or neuromodulators due to similar shapes, activating or blocking natural receptors.

Cycle of Neurotransmitters

Neurotransmitters are synthesized in the cell body and transported to axon terminals, released from synaptic vesicles upon calcium-induced depolarization, bind to receptors (agonizing or antagonizing), then are deactivated by enzymes or reuptake.

MDMA Action

MDMA gets into the cell by the serotonin transporter, interrupts the packaging, causing serotonin to leak out, whilst also reverses the serotonin transporter, pumping out serotonin.

Hormones

Signaling molecules produced by glands and transported through the blood to regulate physiology (muscles, neurons, etc.) and behavior.

Glutamate

Main excitatory neurotransmitter in the brain; released by ALL excitatory neurons.

Glutamate Synthesis

Glutamic acid, an amino acid that acts as a neurotransmitter; synthesized in the brain from glutamine.

Glutamate Receptors

NMDA, AMPA, Kainate (ion channels); metabotropic glutamate receptors (G-protein-coupled).

NMDA Receptor Antagonists

Alcohol and ketamine are both NMDA antagonists, leading to general sedative effects, memory impairment, dissociative or hallucinogenic symptoms, and potential risk of psychosis.

NMDA Receptors and Psychosis

NMDA receptor activity is critical for learning, memory, perception, and synaptic plasticity; genetic studies identify NMDA receptor genes as relevant in schizophrenia but the picture remains unclear.

GABA

Primary inhibitory neurotransmitter; prevents neurons from firing uncontrollably.

GABA Synthesis

Produced from glutamic acid.

GABA Receptors

GABA-A receptors (ion channels) and GABA-B receptors (G-protein-coupled).

GABA and Seizure Disorders

Linked to abnormality of GABA neurons and/or GABA receptors causing sudden excessive activity of neurons. Can cause muscle convulsion, but not always.

Dopamine

Neuromodulator that originates from the brain stem. involved in motor control basal ganglia and motivation/reward learning.

Dopamine Synthesis

Synthesized from the amino acid tyrosine, found in cheese, nuts, and avocados; converted into L-DOPA, then into dopamine.

Dopamine and Parkinson's

Death/loss of dopamine cells leads to motor tremor, cognitive impairments, and dementia, with reduced executive function.

Reward

Receiving money is a positive experience (losing it is negative) because it is associated it with items or activity of value. If unexpected the feelings are often more intense

Drug Addictions

Chronic relapsing disorder with compulsive drug-seeking and drug-taking behavior, taking place at the expense of other activities, persisting despite adverse consequences.

Cocaine Action

Blocks the reuptake of dopamine into the presynaptic neuron, causing excess dopamine to stimulate the post-synaptic neuron.

Amphetamine Action

Reverses uptake transporter, actively expelling DA and NA out of the neuron preventing DA uptake

Addictive Drugs and Reward

Addictive drugs hijack the reward response to increase dopamine, coding it as more positive than expected.

Addiction and Free-Will

Drugs initiate 'wanting,' leading to urges and cravings. Cognitive control is reduced due to impaired prefrontal cortex function.

Noradrenaline Synthesis

Noradrenaline is produced after dopamine. through dopamine beta-hydroxylase.

Noradrenaline Functions

Arousal and alertness, vigilance, focusing attention, coding salience, and memory formation and retrieval.

Noradrenaline (NA) = “Norepinephrine”

Originated from the brain stem, innovates the medulla and helps with flight or fight response.

4 F's

Fight, Flight, Freeze, Fornicate.

LC/NA Activity

Stress and anxiety, balance for optimal performance of inverted U, at moderate levels it consolidates decisions adaptive to behavior, switch between different behaviors.

Locus Coeruleus (LC) - Neuron Firing

High rates rapidly follow a transient noxious or extremely positive stimulus/event (lots of NA released).

NA release and the pupil

When noradrenaline spikes, decisions are made, a change from one perception to another, the pupils dilate.

Serotonin

Acts as a neuromodulator, influencing activity of various neurons, important in sleep, arousal, appetite, temperature, working memory, hallucinations, and mood.

Serotonin Pathways

All serotonin in the brain is synthesized and released from neurons originating in the Raphe Nuclei (Raphe = midline in the brain stem).

Serotonin (5-HT) - Receptor Subtypes

There is a huge number of different types of receptors that our natural serotonin chemicals act on depending on where they are released.

Serotonin in Depression and Personality

Modulating sleep, arousal, appetite, body temperature, cognitive functions (like working memory), hallucinations, as well as mood.

Depression and Serotonin

Brain imaging studies show a reduction in some types of serotonin receptors in the brain of unmedicated depressed patients.

Depression and Serotonin Vulnerability

Genes, 5-6x more likely after stressful events, that place you at risk plus stressful life events increases the likelihood of depression .

MDMA Psychopharmacology

It influences the protein that transports serotonin into the vesicles. With serotonin transporters through a mechanism, it also reverses the serotonin transporter and gets pushed out of the cel and then released into the synapse.

Peptides

building blocks of protein, formed through the breakdown of proteins, mainly serve as neuromodulators, like a co-neurochemical.

Heroin

Are a full agonist of endogenous opioid receptors,it mimics the bodies natural ones responsible in pain and pleasure and is more addictive

Buprenorphine

stimulates the same natural receptors, but it has less of a psychoactive effect and it tries to outcompete any other sort of opioid drugs that you might be using to try reduce the addictive effects from those recreational drugs.

Naloxone

it is a full antagonist, it does not have any stimulating effect on the opioid receptors, and these are used mainly in overdose situations.

Methadone

It is just like a replacement for heroin, has the same level of activity, but it has a much slower time course, so it is like a slow drip heroin (hence less addictive).

Endocannabinoids

internal cannabinoids, that are similar to the active ingredients of cannabis, which in turn causes effects through the CB1 and CB2 receptors. it dampens down and modulates neurons with serotonin.

Nucleosides - Adenosine

Adenosine stimulates a pre-synaptic neuron to promote sleepiness and caffeine is antagonist of this.

Gases and Nitric Oxide

Dissolved gasses that function like neurotransmitters; nitric oxide dilates blood vessels.