4) Neurotransmitters & Psychopharmacology Flashcards
Which 2 neurotransmitters carry out most synaptic communication
Glutamate- excitatory
GABA/ glycine (in spinal cord)- inhibitory
Both secreted by terminal buttons
What is psychopharmacology
The study of drug effects on the nervous system
What is an antagonist drug
A drug that opposes/inhibits the effect of a neurotransmitter on a postsynaptic cell
What is an agonist drug
A drug that facilitates the effect of a neurotransmitter on a postsynaptic cell.
How can the rate of neurotransmitter synthesis be increased
Administering a precursor, so acts as an agonist
What controls neurotransmitter synthesis
Enzymes. So drugs that inactivate an enzyme serve as antagonists
How do drugs effect storage and release of neurotransmitters?
A drug molecule binds to a site on a transporter and inactivates it, as it is occupying the same where enzymes usually work. Since nothing can be synthesised, the vesicle is empty and nothing is released when the vesicle fuses with the presynaptic membrane (Serves as an antagonist)
Once some drugs bind to the postsynaptic receptor, what 2 effects can it have?
Serve as a:
direct agonist/antagonist =
> drug that binds directly onto the receptor of interest
Indirect agonist/antagonist=
drug attaches to a binding site on a different postsynaptic receptor, which facilitates/inactivates action of the receptor of interest.
In what 2 ways can drugs effect reuptake/neurotransmitter destruction
1) Interfere with the action of transporter molecules responsible for reuptake of neurotrans molecules back into the terminal buttons of the presynaptic molecule. It does so by blocking and inactivating them
2) Binds with enzyme activation sites which prevents the process of destroying excess neurotransmitters molecules in the cleft, since the binding sites have been occupied with the drug
What do both ways of effecting reuptake/destruction of neurotransmitter have in common?
BOTH of them prolong the presence of neurotransmitter in the synaptic cleft, so serve as AGONISTS
Placebo is..
an inert substance instead of the physiologically active drug, used as an experimental control for an administered drug
Placebo effect is..
The behavioural effects observed of taking/not taking a drug (feelings of getting better on the placebo).
Helps to conclude if any actual changes are caused by the drug.
Nocebo effect is..
Patient feeling worse after even when no effect should have occurred.
Where is the neurotran ACh (Acetylcholine) secreted from?
By the EFFerent nerves axons in the CNS.
Also found in parasympathetic branch of ANS
What is ACh’s key roles?
- ALL muscular movement accomplished by ACh release.
- Involved in REM sleep regulation, memory, perceptual learning
Who discovered ACh
Otto Loewi
Describe the 2 types of ACh receptors, what stimulates them and what blocks them
1) Nicotinic receptor:
ionotropic (direct), stimulated by nicotine
It is blocked by curare (poison serves as muscle relaxant/paralysis).
It acts at the neuromuscular junction between nerve cells and muscles
2) Muscarinic receptor:
Metabotropic (indirect), produces the parasympathetic nerve effects of heart, smooth muscles, glands
Stimulated by muscarine, blocked by atropine (prevents ACh from depolarising the post-synaptic membrane, stops impulse generation to this cell)
Explain the first 3 stages of transmission across a cholinergic synapse (ACh present at these types of synapses)
1) AP arrives at the presynaptic membrane, Ca2+ channels open and calcium ions enter the presynaptic neuron
2) Calcium ions cause vesicles to fuse to the presynaptic membrane and then release ACh into the cleft
3) ACh diffuses across the cleft and binds to neuroreceptor sites in post-synaptic membrane
Explain the last 2 stages of cholinergic synapse transmissions
4) Sodium channels open and ions diffuse into post synaptic membrane, causing depolarisation and an AP to fire
5) Ach- ase (enzyme) breaks down ACh, with leftover products diffusing back into presynaptic neuron where ACh is resynthesises using ATP for next transmission
What is the name of the post synaptic membrane at a neuromuscular junction
The muscle fibre membrane is called the sarcolemma.
What does depolarisation of the sarcolemma lead to?
Muscle contraction
Which neurotransmitters belong to the compound family The Monoamines?
Dopamine, serotonin, noradrenaline (norepinephrine) , adrenaline (epinephrine)
They all primarily effect mood and anxiety. What is dopamine more specifically involved with?
Pleasure, with more of this reward chemical sent to the decision making area of the brain, in order to help feed our pleasurable behaviours i.e. food, sex, water
Define addiction
state of engaging in excessive compulsive behaviours, reinforcing a certain behaviour, since it’s pleasurable. Tends to be followed with a loss of control of intake
