Chemistry of Behaviour Flashcards
Neurochemistry
chemical processes in the neurosystem (endogenous system, present in the system)
Neuropharmacology
effects of drugs on neurosystem (exogenous processes, compound)
Ionotropic receptor
- Ligand gated
- Opens ion channel
- Fast
Metabotropic receptor
- G protein-coupled
- Second messengers: g protein activation
- Slow, longer lasting
Receptors
protein molecules embedded in the postsynaptic membrane that recognize a specific transmitter
Receptor agonist
drugs that block the transmitter and open gate -> normal effects of the transmitter on that receptor
Competitive antagonist
neurotransmitter block the receptor and the agonist to act
Non-competitive agonist/antagonist
they bind on different places
Cholinergic pathways
Cholinergic pathways -> play a role in muscle control and memory
- Nicotine receptors -> ionotropic (important in muscular system)
- Muscarinic receptors -> metabotropic (role in memory)
Dopaminergic pathways
- Mesostriatal pathway
○ From substantia nigra (black matter) to the striatum
○ Role in motor control
○ Main area affected in Parkinson’s disease - Mesolimbocortical pathway
○ From VTA to limbic system
Reward/reinforcement (change in dopamine level)
Noradrenergic pathway
- Norepinephrine = noradrenaline, from locus coeruleus to broadly area in the brain
- Active role in body and the brain (sympathetic nervous system)
○ Connect neural system to the body (active response)
○ Activating mental functions in the brain
Serotonergic (5-HT) pathways
- from raphe nuclei (in the midbrain)
- they project to mostly all the part of the brain -> control of mood, anxiety and sleep
2 type of drugs
1) Medicine used in treatment of a disease
2) Drugs of abuse, used recreationally
Effective dose 50 (ED50)
dose at which 50 % of the effect is shown or test population show effects (y or n)
Lethal dose 50 (LD50)
dose at which 50 % of the population dies
Therapeutic index
Window between ED50 and LD50.
The therapeutical index refers to the separation between useful doses of the drug and dangerous doses.
Metabolic tolerance
organ system become more effective in eliminating the drugs from the bloodstream
Functional tolerance
target tissue may show altered sensitivity to the drug (regulation of the number of receptors)
Cross-tolerance.
Tolerance to a drug often generalised to other drugs belonging to the same chemical class
sensitization
Some drugs responses can become stronger with repeated treatments, rather than weaker
Regulation of the number of receptors for drugs
- When the drug is an agonist (increase activation) -> down-regulation (few receptor are needed for the same effect)
- When the drug is an antagonist -> up regulation of the number of receptors in the membrane (member of receptors became smaller)
Antipsychotics
Antipsychotics -> affects post-synaptic neurons
Typical:
- Dopamine D2 antagonist
- Reduce positive symptom of schizophrenia
Atypical:
- S-HT antagonist
- Reduce negative symptoms of schizophrenia
Antidepressants
Antidepressants -> use to cure depression
- MonoAmineOxidase (MAO) inhibitor: inhibits an enzyme in the presynaptic that inhibits the degradation of this neurotransmitter -> more neurotransmitter remaining present in the pre-synaptic cells and more available to be released.
- Tricyclic antidepressants: reuptake inhibitor -> not very specific (inhibit a lot) -> many inhibit path that don’t want to inhibit
- SSRI: selective serotonin reuptake inhibitor -> more specific and beneficial (increase serotonin -> benefit patient)
Anxiolytics
Anxiolytics -> treat anxiety disorder (family of sedatives)
- Benzodiazepines: Gaba agonist that activate the same receptor as Gaba (inhibitor neuron) and reduce nervous system activity
