W3 - Neurotransmitters & Psychopharmacology ✅ Flashcards
What is psychopharmacology?
The study of the effects of drugs on the nervous system and on behavior
Antagonist vs Agonist drugs
Antagonist: opposes or inhibits the effects of a neurotransmitter.
Agonist: facilitates the effects of a particular neurotransmitter.
What are 4 main sites of action?
Site of action: the location at which molecules of drugs interact with molecules and affect biochemical processes
- Production of neurotransmitters
- Storage and release of neurotransmitters
- Effects on receptors
- Effects on reuptake
Drug’ effects on Receptors?
Direct: binds with and activates a receptor -> mimics the effects of a neurotransmitter
Indirect: attaches to a binding site on a receptor and affects receptor -> no interference with neurotransmitter’s binding site.
Effects on re-uptake/destruction of neurotransmitter?
- Drug attach to transporter molecule -> inhibit to prevent re-uptake
- Drug binds to enzyme that destroy neurotransmitter -> prevent destruction
What is the placebo + nocebo effect?
Placebo effect:
- an inert substance given to an organism in place of a physiologically active drug
- used as control for the mere administration of a drug
Nocebo effect:
- when people can feel worse after an intervention that should have no ill effects
Functions of other neurotransmitter (aka NOT glutamate and GABA)
- Modulate different areas of the brain (circuit of neurons for a particular function)
- Not used for transmitting information
Function and features of Acetylcholine - ACh
- Primary neurotransmitter secreted by efferent axons
- Control muscular movement
- Involves in regulating REM sleep
- ACh receptors: nicotinic and muscarinic
What are 2 ACh receptors?
- Nicotinic receptor:
- Ionotropic receptor
- Stimulated by nicotine + blocked by curare - Muscarinic receptor:
- Metabotropic receptor
- Stimulated by muscarine + blocked by atropine
What are drugs that affect ACh?
Botulinum toxin:
- Antagonist
- Prevent release by terminal buttons
Black widow spider venom:
- Agonist
- Trigger release -> convulsions
What is meant by addiction, tolerance, dependence + reward pathway?
Pathway: ventral tegmental area (VTA) -> nucleus accumbens -> (amygdala) -> prefrontal cortex
Addiction: engages in compulsive behaviour and behaviour is reinforced, loss of control for limiting intake
Tolerance: no longer responds to a drug -> a higher dose is required to achieve the same effect
Dependence: only functions normally only when drug is present -> physical disturbance when the drug is withdrawn
Explain dopamine treatment for Parkinson’s disease?
- Nigrostriatal system: connects substantia nigra and striatum (basal ganglia)
- Involved in the planning, execution, and control of movement.
- Dopamine acts as a neurotransmitter that modulate the activity of the striatal neurons.
=> Dopamine is used to treat Parkinson’s disease (caused by degeneration of the nigrostriatal system)
Features and functions of serotonin + serotonin pathways
- also called 5-HT
- serotonin is involved the control of:
1. appetite
2. sleep
3. memory and learning
4. temperature regulation
5. cardiovascular function
6. muscle contraction
7. endocrine regulation
8. depression - is produced by a group of neurons located in the raphe nuclei.
- distinct pathway: serotonergic projection to the prefrontal cortex -> regulating mood, emotion, and cognition.
Drugs that affect the activity of serotonin?
- LSD (acid)
- stimulates centers of the sympathetic nervous system in the midbrain -> pupillary dilation, increase in body temperature, and rise in the blood-sugar level.
- also has a serotonin-blocking effect - MDMA (ectasy)
- noradrenergic and serotonergic agonist
- has excitatory and hallucinogenic effects: heightened perception, stimulation, reduced appetite and elevated mood
- prevent re-uptake and bring more serotonin to synapse
What are the adverse short and long term effects of serotonin?
short-term (post-ectasy):
- clouded thinking
- hyperthermia
- disturbed behaviour
- jaw clenching
long-term:
- neurotoxicity (damaged of serotonin neurons in the brain)
- impairment of verbal and visual memory
- depression (anti-depressant medications increase serotonin levels by blocking re-uptake)
Function and features of norepinephrine (NE)/nonadrenaline + epinephrine?
- both a hormone and neurotransmitter
- secreted by adrenal gland
- used to give body sudden energy for stress response
- drugs that inhibibit NE is effective to treat depression
- act in bloodstream
=> slightly different to epinephrine (still same function):
- secreted in adrenal medulla
- neurotransmitter in the brain
Function and features of amino acids (recap)
most common neurotransmitter in the CNS: glutamate, GABA and glycine
glutamate: excitatory neurotransmitter
-> NMDA - specialised glutamate receptor
GABA (brain)/glycine (spinal cord): inhibitory neurotransmitters
- regulate/control the expressions
- imbalance of GABA is associated with bipolar disorder, schizophrenia and anxiety disorder
What is meant by tranquilizers?
- belongs to benzodiazepine group
- indirect agonist of GABA receptor
- has tranquilizing/calming effects
- examples: Valium, Xanax
