Drugs Flashcards
How does a synapse work?
- Chemical-electric signal of activated neuron reaches the end of axon
- Electric signal ends
- Neurotransmitters are released from axon into synapse
- Neurotransmitter binds to the receptors on dendrites
- Neurotransmitter either excites or inhibits the neuron
What does neurotransmitter bind to on the postsynaptic neuron?
Dendrites
What are the 2 effects that neurotransmitters can have on the receptor neuron?
Excitatory or inhibitory
What is dopamine?
A neurotransmitter –> NOT a hormone
What is dopamine involved in?
Involved in regulation of movement, reward and punishment, pleasure, energy
Which (illegal) drugs affect dopamine?
Every drug that affects feelings of pleasure, including Cocaine, Amphetamine, opiates, marijuana, heroin and PCP
These drugs temporarily increase levels of dopamine
Is dopamine excitatory or inhibitory?
Has effects that are both excitatory and inhibitory.
Is adrenaline excitatory or inhibitory?
Excitatory neurotransmitter
Where is adrenaline released from?
Adrenal medulla
What are the catecholamines?
Adrenaline, noradrenaline and dopamine
Where are the catecholamines released from?
The adrenal medulla
What are the effects of adrenaline?
Involved in arousal and alertness:
- increase the heart rate
- increase blood pressure
- expanding the air passages of the lungs
- enlarging the pupil in the eye
- redistributing blood to the muscles
Is noradrenaline excitatory or inhibitory?
Excitatory neurotransmitter
What is noradrenaline involved in?
Involved in arousal and alertness, energy and feelings of pleasure
What drugs affect noradrenaline?
Stimulants
Is serotonin excitatory or inhibitory?
an inhibitory neurotransmitter
What is serotonin involved in?
involved in emotion and mood, balancing excessive excitatory neurotransmitter effects in your brain
What drugs affect serotonin levels?
Alcohol, Hallucinogens, Stimulants, Anti-depressants
Is acetylcholine excitatory or inhibitory?
ACh has excitatory actions at the neuromuscular junction, at autonomic ganglion, at certain glandular tissues and in the CNS. It has inhibitory actions at certain smooth muscles and at cardiac muscle.
What is ACh involved in?
Acetylcholine is the chief neurotransmitter of the parasympathetic nervous system, the part of the ANS that contracts smooth muscles, dilates blood vessels, increases bodily secretions, and slows heart rate.
Involved in movement, memory function, motivation and sleep
Is ACh adrenergic or cholinergic?
Cholinergic
What drugs affect ACh?
PCP and hallucinogens, Marijuana, Stimulants
Is GABA excitatory or inhibitory?
Inhibitory neurotransmitter
What is GABA involved in?
arousal, judgment and impulsiveness
What drugs affect GABA?
Opiates, Alcohol, Marijuana
Is glutamate excitatory or inhibitory?
Excitatory neurotransmitter
What drugs affect glutamate?
Alcohol
Cholinergic vs adrenergic?
The main difference between adrenergic and cholinergic is that adrenergic involves the use of neurotransmitter adrenaline and noradrenalin whereas cholinergic involves the use of neurotransmitter Acetylcholine.
What are endorphins involved in?
Substances involved in pain relief and reward/punishment
What drugs affect endorphins?
Opioids
What drug related factors can affect the way they work in people?
Nature of drug Amount Route of administrations Quantity Quality Combinations Other medication
What person related factors can affect the way they work in people?
Tolerance
Physical health
Mental health
Social stressors
What system does cocaine primarily work on?
reward system (Limbic system, amygdala, pre-frontal cortex)
Normally, in pleasure circuit dopamine is released, it activates the next neuron and is transported back to be absorbed.
How does cocaine affect this?
Cocaine binds to transporter system and prevents the reuptake of dopamine and serotonin
This leads to prolonged presence of dopamine and serotonin
What does cocaine prevent the reuptake of?
Dopamine and serotonin
What is the effect of prolonged presence of dopamine and serotonin?
Causes intense pleasure, impulsivity and alertness
Constant use results in down regulation of receptors by the body. Why is this? What does this result in?
In an effort to reduce the effects of dopamine
This results in craving for more drug leading to dependence
The regions of the brain comprising the “reward system” use which neurotransmitter to communicate?
Dopamine
What circuit does Amphetamines & Met-amphetamines work on? Why?
Pleasure circuit as these are chemically similar to dopamine and norepinephrine
How do Amphetamines & Met-amphetamines enter the neuron?
Directly enters the neuron through cell membrane
What do Amphetamines & Met-amphetamines bind to?
Binds to molecules that carry dopamine and norepinephrine and reaches terminal
It enters the vesicles containing the 2 neurotransmitters and releases them
In usual circumstances, what happens when there is excess of a neurotransmitter?
Excess of neurotransmitter is usually destroyed by enzymes
How do amphetamines affect the destroying of excess neurotransmitters?
Amphetamines prevents the destruction –> the excess neurotransmitters are released in the synapse
Effects of dopamine?
euphoria and impulsivity
Effects of norepinephrine?
alertness and anti-fatigue feeling
The dopamine transporter normally moves unbound dopamine from the synapse into the sending neuron.
How does ritalin and cocaine affect this?
Both BLOCK the dopamine transporter, causing dopamine to build up in the synapse
How does methamphetamine affect dopamine?
Fools the cell into dumping dopamine into the synapse, causing a surge of exhilaration
What does stimulant induced mania involve?
euphoria, increased alertness, increased vigor, decreased food intake, decreased sleep, increased familiarity
How can stimulants affect mental health?
- Stimulant induced mania
- Psychosis
- Depression
What pathway does opiates affect?
Opiates inhibit pain signals in pain pathway
Opiates also activate mesolimbic reward system of brain by releasing dopamine and reducing noradrenergic activity
i.e. reduce pain but also create pleasure
How do opiates increase dopamine levels?
By attaching to their mu receptors, exogenous opioids reduce the amount of GABA released.
Normally, GABA reduces the amount of dopamine released in the nucleus accumbens.
By inhibiting this inhibitor, the opiates ultimately increase the amount of dopamine produced
What is the endocannabinoid system?
Plays a critical role in the nervous system’s normal functioning
What is anandamide?
brain lipid that binds to cannabinoid receptors and mimics the psychoactive effects of plant-derived cannabiniod drugs
How does anandamide affect the brain?
affects brain areas that influence pleasure, memory, thinking, concentration, movement, coordination, and sensory and time perception.
What does THC bind?
THC in marijuana binds with CB receptors like Anandamide
How does THC affect the brain?
THC is able to alter the functioning of the hippocampus and orbitofrontal cortex affecting memory and learning
THC disrupts functioning of the cerebellum and basal ganglia, brain areas that regulate balance, posture, coordination, and reaction time
What pathway does THC affect?
THC stimulates neurons in the reward system to release the signalling chemical dopamineby removing inhibition by GABA
How does THC increase dopamine?
by removing inhibition by GABA
What are synthetic cannabinoids?
cannabinoids refer to a growing number of human-made mind-altering chemicals sprayed on dried, shredded plant material or vaporised to produce a high
effects are severe and dangerous - ‘zombie’
3 aspects of management of drug use?
- Biological
- Psychological
- Social
What are biological managements for drug use?
- Antidote (e.g. Naloxone)
- Detoxification
- Substitute (e.g. Methadone)
- Deterrence (e.g. Disulfiram)
- Anti-craving (e.g. Accamprosate)
What is Naloxone?
A medication used to block the effects of opioids. It is commonly used to counter decreased breathing in opioid overdose.
What is methadone?
Methadone is a synthetic opiate manufactured for use as a painkiller and as a substitute for heroin in the treatment of heroin addiction.
What is Disulfiram?
A drug used to support the treatment of chronic alcoholism by producing an acute sensitivity to ethanol
What is Accamprosate?
used along with counselling to treat alcohol dependence
Psychological managements for drug use?
Motivational interviewing Brief interventions CBT (cognitive behavioural therapy) Contingency management Self help
etc…
Social managements for drug use?
Employment Training and education Housing Relationships Financial Criminal/Justice support
Purpose of Benzodiazepines during alcohol withdrawal?
Seizures and tremors Difficulty sleeping and restlessness Nausea and vomiting Irritability Chills and sweats Headaches Pain Anxiety Panic
