Endocannabinoid system
affects pain modulation, memory, appetite, inflammatory + other responses
CB1
~ primarily found in brain + CNS
~ located at pre-synpase of glutamate + GABA neurotransmission
~ THC binds
THC
TetraHydroCannabinol
CB2
~ mostly found in organs associated w/ immune system
~ activation does not cause psychoactive effects like CB1
~ CBN binds
CBN
cannabinol
Anadamine
~ natural endocannabinoid that binds to brain cannabinoid receptors
~ not stored, synthesised when + where needed
~ binds to presynaptic CB1 = dopamine release in NAc
Low dose of anadamine
~ anxiolytic properties
~ relaxation + friendliness
~ impaired STM
~ loss of temporal awareness
High dose of anadamine
~ panic
~ toxic delirium
~ psychosis
Name locations where CB1 receptors are found.
~ hypothalamus (memory)
~ basal ganglia (movement)
~ cerebellum (movement)
CB1 activation causes…
decrease in Ach release
Acute toxic psychosis
ST: delirium w/ confusion, hallucinations, acute paranoid state
LT: schizophreniform psychosis, depression, depersonalisation
Cannabis + Schizophrenia
genetic disposition to schizophrenia associated with increase cannabis use
Cannabis + Addiction
~ 9% of users = abuse + dependence
~ 50% of users = impaired control over use
~ mesolimbic-dopamine pathway (increase of dopamine in NAc)
Cannabis Withdrawal
~ occurs in combo w/ decrease in mesolimbic-dopamine function
~ mild comp. other drugs
~ might contribute to cannabis dependence through -ve reinforcement
Cannabis Tolerance
~ chronic administration causes global down regulation in activity of cannabinoid receptors
~ lower dopamine release
Chronic users paradox
chronic users need less cannabis to get high
Possible explanations of chronic users paradox
1) users focus on the effects they want to achieve - novice users unable to appreciate effects
2) fat soluble nature of THC + its metabolites = stored in fast then released gradually = higher basal lvl than novice
3) Liver more efficient at metabolising THC = metabolites more quickly available
Symptoms of cannabis withdrawal
~ anxiety
~ weight/appetite loss
~ chills + shaking + sweating
~ depressed mood
