Lecture 26- Marijuana Flashcards
Exam 3
What does the endocannabinoids system do to neurotransmitters?
- inhibits the release of many neurotransmitters including
- glutamate
- GABA
- noradrenaline
- dopamine
- and serotonin
Where are endocannabinoids made, stored, and released? Why?
- in the postsynaptic neuron
- because endocannabinoid system follows retrogradetransmission
Why are endocannabinoid receptors on the presynaptic neuron?
- receptors (metabotropic) are on the presynaptic terminal to inhibit the release of whatever neurotransmitter the presynaptic neuron would typically release
Is marijuana considered a dirty drug?
- cannabinoid receptors (CB1 and CB2) are found all over the brain and NS
- But, bc cannabinoids only work on these specific receptors, marijuana is not considered a dirty drug
In what ways do marijuana’s acute physicological effects very per user?
- strength
- intensity
- and duration
however, generally quite benign
Acute physiological effects- cardiovascular (specifically eyes)
- conjunctiva (bloodshot eyes)
- due to vasodilation
- apparent after around 1 hour
- dose-dependent
acute physiological effects- cardiovascular
- icreased heart rate and BP
- apparent after around 20 minutes and lasts around 1 hour
- dose-dependent
Acute physiological effects: motor
- decreased motor activity
- drowiness, although decreases REM sleep with higher doses
- however, dose not decrease talkativeness lol hahahaha
Other acute physiological effects
- dry mouth
- thirst
- changes in body temp
- respiration changes
- hunger
- nausea
- headache
- dizziness
Chronic physiological effects- respiratory
- decreased proper lung function that may be reversible
- marijuana cigs contain more tar and carcinogens than tobacco, and is held in lungs longer than tobacco smoke
- but, difficult to determine which contributes more as marijuana users typically smoke cigarettes
Emphysema marijuana vs tobacco
- 93% of marijuana smokers
- 66% of tobacco smokers
Chronic physiological effects- cardiovascular
- no significant long-term effects in healthy users
- acute effects potentially dangerous in individuals w heart disease
Chronic physiological effects- immune
- no significant long-term effects even though it can have immunosuppressant effects
Chronic physiological effects-Reproductive
- decreased sperm count/motility
- nonovulatory menstrual cycles
Learned psychological effects of marijuana
- mechanical: learning to inhale and hold the smoke to maximize absorption
- perception: learning to perceive the physical and psychological effects
- labeling- learning to label the effects that are pleasant
Who is most sensitive to cannabis effects?
experienced users are more sensitive than newbies
Behavioral psychological effects of marijuana
- decreased psychomotor activity
- relaxed/tranquil feeling
- some feel excited/restless (novice users)
- keener perception- likely anecdotal, but no scientific basis (however, decreased sensitivity to pain)
- impaired reaction times- inconclusive yet critical for driving
Sexual function-psychological effects
- varied effects- increased pleasure in some and decreased desire in otheres
- long-term use can lead to impotence in men and reduced sex drive in women
Cognitive psychological effects
- impaired stm at low doses
- adoescents may be more vulnerable
- decreased (lengthened) perception of time
- impaired judgement and attention/vigilance
What is the mechanism underlying impaired stm on weed?
- unknown, byt likely due to reduced NT, including impaired LTP and LTD
- LTP and LTD- strengthening or weakening of synaptic connections- neural correlates of learning and memory
emotional psychological effects of marijuana
- typically carefree and relaxed feeling (euphoric, content, happy, and excited)
- anxiety/dysphoria more common than expected (around 1/3): suspiciousness/paranoia in some cases (usually ineperienced users)
Marijuana use and mental disease link
- some evidence links marijuana use and mental disease (anxiety, depression, achizophrenia/psychosis)- inconclusive
- more likely that the drug use unmasks an issue already genetically present
- or, that the drug use is correlated w mental illness (but not the cause
Is marijuana reinforcing?
- bc CB receptors are found everywhere it is difficult to understand how cannabis activates the reward pathway, so overall unsure
Tolerance
- animal models show tolerance develops to marijuana
- human studies less clear- factors include dose and use duration
- mechanisms of tolerance unclear but likely in heavy users
Withdrawal symptoms from weed
- symtpoms include sleep disturbances, nausea, and restlessness
- associated w sustained heavy use
neuroadaptations do occur following chronic use
Amotivational syndrome
- not seen in all marijuana users, and also seen in non marijuana users
- so, likely a combination of pre-existing personality characteristics and some drug effects
Is weed a gateway drug?
- vast majority of marijuana users do not go on to use hard drugs
- but 90% of cocaine users have tried/used marijuana
- if there is a stepping stone, it is likely alcohol and nicotine (alc/nic to marijuana to hard drugs)
What is the correlative vulnerabilities theory?
right combination of circumstances along with positive experience w a drug can lead to misuse
