Kap 4 . Psychopharmacology and Neurotransmitters Flashcards
Psychopharmacology
the study of the effects of drugs on the nervous system and behavior
Exogenous
produced outside the body
(rules out chemical messengers produced by the body, like neurotransmitters, neuromodulators, or hormones)
The definition of a drug
an exogenous chemical not necessary for normal cellular functioning that significantly alters the functions of certain cells of the body when taken in realtively low doses.
drug effects
the changes we can observe in an individual´s physiological processes and behavior
sites of action
are the locations where drug molecules bind with molecules located on or in cells of the body, to affect some biochemical processes of these cells
The steps of Pharmacokinetics
- absorbed
- distributed within the body
- metabolized
- excreted
Peritoneal cavity
the space that surrounds the stomach, intestines, liver and other abdominal organs
Intraperitoneal (IP) injection
injection through the abdominal wall
- not as rapid as IM
- commonly used in small laboratory animals
Intramuscular (IM) injection
- Directly into a large muscle (upper arm, thigh, buttocks)
- more rapid than IP
Subcutaneous (SC) injection
- beneath the skin
Intracerebral administration
a procedure to study the effects of a drug in a specific region in the brain, where a researcher inject a very small amount of the drug directly into the brain
- rapid druguse
Intracerebroventricular (ICV) adminitration
- to achieve widespread distribution of a drug on the brain, you can pass the blood-brain barrier by injecting the drug into a cerebral ventrical
- not used often on humans, but on certain types of infections, antibiotics might be delivered this way
- rapid druguse
Oral Administration
- drugs though mouth –> digestive tract –> pass metabolism in the liver
- some drugs will be destroyed by stomach acid and will be ineffective if taken orally
- reach the site of action, slowly
often used in therapeutic drugs
Sublingual administration
placing a drug beneath the tongue
- drug is absorbed into the bloodstream through the capillaries that supply the mucous membrane that lines the mouth
Topical administration
drugs absorbed through the skin
insufflation
sniffing / snorting
Affinity
the readiness with which two molecules join together - for the sites to which they attach
High affinity = effect low concentration
Low affinity = higher dose to get same effect
dose-response curve
the best way to measure the effectiveness of a drug
se figur 4.4 s. 96
Therapeutic index
a measure of a drug´s margin of safety
Tolerance
when a drug is administered repeatedly its effects diminish
Sensitization
when a drug is administered repeatedly its effects becomes more and more effective
withdrawal symptoms
“opposite effect of the drug”
If an addicted drug uses stops taking the drug. For example heroin produces euphoria, relaxation, withdrawl produces dysphoria (feeling of anxious misery), agitation
Receptor downregulation
“first compensensatory mechanism”
decrease receptor availability
The receptors become less sensitive the drug and their affinity for the drug decreases, or. the receptors decrease in number
” second compensenstory mechanism”
involves the process that couples the receptors to ion channels in the membrane or the production of second messengers.
Two spesific amino acid are the most common/important neurotransmitters in CNS
Glutamate and GABA
4 major types of glutamate receptors
Ionotropic
1. NDMA receptor (important role in the cellular basis of learning and memory)
2. AMPA receptor ( –II – )
3. Kainate receptor
Metabotropic receptor
4. Metabotropic glutamate receptor. (presynaptic autoreceptors)
glutamine excitotoxicity
produces when, too much glutamine stimulation in the synapse
- it damage neurons if prolonged and is belived to be involved in damage to the brain in stroke and amyotrophic lateral sclerosis
Valium
diazepam
Xanax
alprazolam
Benzodiazepines
anxiolytics (anxiety-dissolving)
- used to reduce symptoms of anxiety, reduce seizure activity, and produce muscle relaxation
Botulinum toxin
Botox
Why are does the drug effectivness vary?
They vary because they have different site of action and vary in their affinity for their binding sites
Agonist
This are the substances that promote the activity of a neurotransmitter and thereby either stimulates the release or effect of a neurotransmitter, or it simulates the same effects. You can have direct and indirect agonists.
A direct agonist binds to the sites of a neurotransmitter, and thus kind of pretend to be a neurotransmitter with the same or comparable effect.
A indirect agonist binds to other sites, but thereby stimulates the original action process.
Antagonist
Drugs that reduce the action of a neurotransmitter fall into this category. The direct antagonists bind to the same sites of action of a neurotransmitter, but thereby blocking the access for the real neurotransmitter, whereas an indirect antagonist uses other binding sites, but still
manages to block the original effect.
Placebo
inactive substances, that trigger a placebo effect which is caused by changes in
motivation, expectation or classical conditioning.
“You might belive that there will be an effect so strongly, that you actually get an effect”
Enzymatic Degradation
Enzymes (e.g., acetylcholinesterase) break down the neurotransmitter into inactive components.
Precursor
en forløper er et stoff som fungerer som et utgangsmateriale eller byggestein for syntesen av en annen forbindelse, ofte et aktivt medikament. Forløpere omdannes kjemisk gjennom biologiske eller syntetiske prosesser for å produsere det ønskede stoffet.
