Psychopharmacology colleges
Lecture 1 & 3: Introduction and Refresher biological basis of behavior
Introduction in psychopharmacology (briefly dusting up knowledge on neurotransmitters)
Psychopharmacology in bird’s eye view
• What is a drug or pharmacon?
o An administered substance that influences
physiological processes. Sometimes also body’s
own substances. But not if it is (primarily) a
nutrient).
• Psychoactive substances: influence processes in the brain and hence behaviour,
cognition, affect.
• They can be used for different purposes:
o Therapeutic
o Recreational
Study question: Which two overarching classes of psychoactive substances can be discerned
based on their use? Therapeutic and recreational
What is pharmacology
• Pharmacology studies the influence of substances on biological processes c.q.,
living beings.
• Psychopharmacology focuses on their effects on behaviour, cognition and affect,
incl. their mechanisms in the brain.
Why is this of interest?
1. What are the effects of psychoactive substances that you use? I use quit a bit of
them in your daily life without realizing it (tea, coffee, energy, cigarettes, drugs,
etc.).
2. (Clinical) applications
3. Development of future applications
Pharmacokinetics: how does a substance move through the body?
• Topic is covered in the principles lecture. How do you administered it, how is it
absorbed in the body, this is some extend quite trivial because it isn’t about what it
exactly does. It is important for, for example, medication why does it work faster/better
for some people than others.
To be distinguished from pharmacodynamics: werkingsmechanisme
• To what receptors does the substance bind?
• What effect does the substance have on the receptor? (what does the drug do in the
brain)
Neurotransmitters
In psychopharmacology this means: interactions with neurotransmitters.
Neurotransmission:
• Neurons: they talk to each other.
• Action potential
• Synapse
• Transmitter
o Synthesis (in order to be released, it needs to be synthesised)
(samenvoegen/produceren
, o Release
o Degradation (needs to happen to end the reaction) (afbraak)
• Receptor
Neurotransmitter: work on neurons via receptors.
• Receptors: complex protein chains. We won’t go into that level of detail, just stick to
the basic knowledge.
What is the most typical receptor?
1. Presynaptic
2. Postsynaptic: lots of the effects of the neurotransmitters depend on these receptors.
3. Autoreceptor
What is not a drug target to influence the functioning of neurons? Difficult question!
1. Receptor activation: definitely a target.
2. Metabolite excretion metabolites are the parts in which a molecule is dissembled before
it is being excreted from the body, drugs often don’t influence activity of molecules
anymore in this context.
3. Reuptake blockade
4. Enzyme modulation
5. All of the above are possible targets.
Specific neurotransmitters: total number of neurons (~100.000.000.000, 100 billion).
• Used in a relatively low number of neurons (<1%)
o E.g. NE, DA, 5-HT
o relatively specific targets for drugs!
• Frequently used in neurons (~50% of synapses)
o GABA, Glu
o Also: endocannabinoid receptor in many synapses
• Even though implicated in disorders/effects of compounds
o GABA: alcohol, sedatives, anxiolytics.
o Glu, NMDA: epilepsy, Huntington, aids, dementia, schizophrenia
Problem with specificity of drug targets It is difficult to work with drugs that effect GABA and
glutamate because these substances are so abundant in the brain, that a lot of the most drugs
have side effects
Where do neurotransmitters come from?
Precursors: substances that are needed to construct the neurotransmitters.
• Monoamines (single amine group, NH2):
o Catecholamines: DA, NE, E.
▪ Precursor: tyrosine → DOPA →DA →NE →E
o Indolamines: 5-HT
▪ Precursor: tryptophan.
• Amino acide
o Glu, GABA.
▪ Precursor: glucose
• Achetylcholine
o Precursor: choline/lecithine
• Peptides: oxitocine, endorphins.
o Precursor: amino acids
