Week Eight - Psychopharmacology Flashcards
What is Psychopharmacology?
The study of drug induced changes in mood, thinking and behaviour and the effects of drugs on the NS
What is a drug?
A exogenous chemical not necessary for normal cellular functioning which alters the activity of certain cells of the body.
Psychoactive drugs are typically utilised to do what 2 things?
Alter mood: Stimulant, Depressant or Hallucinogen
Treat psychopathology: Anxiolytics, Antidepressants, Antipsychotics
What are Anxiolytics used for?
To reduce anxious feelings
What are Antidepressants used for?
Used to alleviate negative feelings typical of depressive symptomatology
What are Antipsychotics used for?
Used to treat severe forms of psychotic behaviour, such as hallucinations and delusions
What is Pharmacokinetics?
The process by which drugs are absorbed, distributed, metabolised and excreted by the body.
What does Drug Effectiveness mean?
The ability of a drug to readily produce certain physiological and behavioural effects
What factors mediate the effects of drugs?
How it is administered How often it is administered How rapidly it enters the brain The context in which it is administered Our expectations of its effects
What do drugs need to do in order to be effective?
Reach their site of action within the CNS (typically do so through the bloodstream)
The route of administration effects this rate.
What is the blood brain barrier?
A barrier developed by the brain in order to protect itself against dangerous molecules that may damage brain tissue
How to drugs enter the brain?
Through the BBB (which is only for water-soluble molecules)
How do molecules that are soluble in lipids enter the brain?
They pass through the BBB and enter the cells that line the capillaries of the CNS
What is the best way to measure the effectiveness of a drug?
To plot a Dose-Response Curve (finally reaching a point after repeated administration which does not produce a more stronger effect)
Tolerance is the?
Decrease in effectiveness of a drug administered repeatedly
Sensitisation is the?
Increase in the effectiveness of a drug that is administered repeatedly
What is Contingent Drug Tolerance?
Refers to a demonstration in which tolerance develops only to drug effects that are actually experienced contingent to a behaviour
What is Conditioned Drug Tolerance?
Refers to situations where tolerance effects are maximally expressed only when a drug is administered in the same situation in which it has previously been administered
What is a Placebo?
An innocuous substance that has no specific physiological effect in its own right (incorrect to say they have no effect)
What are the 2 types of drugs that affect synaptic transmission?
Antagonist: A drug that opposes/inhibits the effects of a particular NT on the postsynaptic cell
Agonist: A drug that facilitates the effects of a particular NT on the postsynaptic cell
What is the DIRECT route of an Antagonist and Agonist?
The binding cite at the receptor is the same for the drug and the NT (COMPETITIVE BINDING)
What is the INDIRECT route of an Antagonist and Agonist?
The binding cite at the receptor is different for the drug and the NT (NONCOMPETITIVE BINDING)
Acetylcholine (ACh) properties/role?
First NT ever discovered
Controlling heart rate
Motor movement
Role in Memory (Alzheimer’s is a degeneration of ACh neurons)
What are the 5 biogenic amine NT?
Norepinephrine (noradrenaline) Epinephrine (adrenaline) Dopamine Histamine Serotonin
Which of the 5 biogenic amine NT’s are Catecholamines?
Norepinephrine (noradrenaline)
Epinephrine (adrenaline)
Dopamine
THEY SHARE A BIOSYNTHETIC PATHWAY
Norepinephrine (NE)
Distributed throughout the CNS and PNS
Neurons originate in the pons (locus coeruleus)
They form an excitatory pathway to the cortex known at the RAS - which is responsible for maintaining cortical arousal)
Involved in controlling attention, emotion and eating, regulates organs (eg heart)
Norepinephrine (NE) deficiency results in?
Depression and ADD
What 2 pathways is dopamine located?
The nigrostriatal pathway: Involves voluntary movement.
Deficiencies - Parkinsons.
Ventral Tegmental Area (VTA): Involvement in reward and motivation.
D1 like receptor family consists of?
D1 & D5
D2 like receptor family consists of?
D2, D3 & D4
What is Serotonin (SE) (5-HT) involved in?
Distributed throughout the brain and spinal cord.
Involved in: Control of sleep/wake cycle, mood, impulsive behaviour, and appetite
Serotonin deficiency is related to?
Behavioural problems: Sleep disorders, aggression, besity, anorexia, and depression
What do amino acid transmitters do?
Provide the majority of excitatory and inhibitory neurotransmission in the NS
Explain Ionotropic receptors
Respond to ligand binding by opening an ion channel and allowing ions to flow into the cell, either increasing or decreasing the likelihood that an action potential will fire.
Have an effect only in the immediate region of the receptor
Explain Metabotropic receptors
Do not form an ion channel pore but use signal transduction mechanisms, often G proteins, to activate a series of intracellular events using second messenger chemicals.
Can be more widespread throughout the cell.
The stimulant and reinforcing effects of cocaine and amphetamine and largely mediated by what system?
The Dopamine System
Disruption, destruction and lesions block reinforcing effects of related activity
What is cross tolerance?
One drug can produce tolerance to another drug that act by the same mechanism
What is metabolic tolerance?
It results from changes that reduce the amount of the drug reaching the sites of action
What is functional tolerance?
It results from changes that reduce the reactivity of the sites of action to the drug.
Dopamine increases induced by THV are mediated by?
Cannabinoid and opioid receptors.
MDMA has what properties?
Stimulant and Hallucinogenic
What external factors can make the brain go wrong?
Malnutrition Parental abuse Toxins Infections Trauma
What internal factors can make the brain go wrong?
Developmental problems
Acquired abnormalities
Age-related damage
What do Psychedelics do?
Take away limitations and increases brain flexibility. They inhibit the DMN which regulates executive functioning
