Lecture 3- Drug Addiction

drugs are

chemical compounds which interact with the biochemistry of the body

psychoactive drugs

drugs that influence the way we feel or act

Agonist

Mimics action of neurotransmitter

Antagonist

Blocks the action of neurotransmitter

what is the general reason for drug tolerance

the body is maintaining homeostasis so it just adapts

two types of drug tolerance

metabolic and functional

metabolic drug tolerance

enzymes in the liver become more active so the body gets better at metabolising it then less drug reaches the brain

functional drug tolerance

receptors of brain cells change

pre-synaptic receptors

receptors located on the sending neuron, often involved in regulating neurotransmitter release

post synaptic neurons

receptors on the receiving neuron that respond to neurotransmitters

autoreceptors

special presynaptic receptors that detect the neurotransmitter released by the same neuron often reducing further release

reuptake

the process by which a neurotransmitter is reabsorbed into the presynaptic neuron stopping its action

sensitisation

increased response to a drug with repeated use which can occur with stimulants like cocaine

context dependence

drug effects or craving become linked to environmental cues increasing relapse riskrei

reinforcement system

brain circuits that strengthen behaviour linked to rewards

intracranial self stimulation

when animals self administer stimulation to brain reward areas, showing where the reward system lies

brain stem

controls survival, respiration, heartrate

medullla

found in brain stem and controls autonomic functions like breathing and heartbeat

pons

in brain stem and involved in arousal and communication

midbrain

in brain stem and contains dopaminergic structures