Natural Highs: The Oldest Drugs Flashcards
(33 cards)
From Reefer Madness
to High Economy:
Cannabis
What IS
cannabis,
anyway?
One of the world’s oldest crops (hemp harvested in China 8500 years ago).
However, cannabis is very mysterious.
Current broad use of the term ‘cannabis’ is often vague, unscientific, and confusing.
Unsure if the genus Cannabis is monotypic (one species) or polytypic (three or more
species?)
Why so weird?
ancient origin.
extremely long evolutionary and domestication history (including artificial
selection) – may have wiped out other variants.
widespread geographic dispersal.
prohibition made it hard to investigate scientifically.
By the end of this lecture, you will be
able to…
Describe the botanical profile of cannabis.
Describe key events in the cultivation and use of cannabis
in the US and Australia.
Describe the basic pharmacodynamics and
pharmacokinetics of cannabis.
Describe the benefits and limitations of cannabis as a
medical treatment, based on current evidence.
A ‘third strain’
– ruderalis?
Molecular genetics is providing increasing evidence that cannabis
is a polytypic genus.
Some classify cannabis as three sub-species:
Indica
Sativa
Ruderalis
Ruderalis plants are small and yield relatively little medicine with
low potency?
Seems to have a different flowering and life cycle.
Ruderalis strains are typically avoided by breeders and cultivators.
Medical cannabis is usually indica or sativa strains (whatever they
may be!)
Cannabis in
the US
Hemp grown in North American colonies from early seventeenth
century (by slaves).
American hemp industry peaked before 1860 - declined after
Civil War (loss of slaves; rise of industrialisation).
Medicinal cannabis included in the American pharmacopoeia by
1851.
Imported from India via Britain.
Medical uses were sporadic and ill-defined.
By the early 1900s, US government began experimenting with
domestic production of drugs, including cannabis.
Recreational
uses
Early reports of recreational cannabis use in the US - Southwest
and the port of New Orleans, c.1900.
New term - ‘marijuana’ - smoked version of cannabis indica.
Racist fears about Mexican immigrants and drug trade.
In 1915, El Paso, Texas was first US municipality to ban the nonmedical cannabis trade (fears of Mexican drug trade).
Street name was ‘muggles’!
Recreational marijuana smoking spread rapidly during the 1920s:
industrial hubs like Kansas City and Chicago – working class, youth,
Black associations.
jazz musicians like Louis Armstrong brought ‘reefers’ to various gigs
across the country
The 1950s and 1960s
1950s Beatnik movement – cannabis use.
1960s – growing counterculture.
American soldiers sampled Thai and Vietnamese varieties while
serving in Vietnam.
Mostly imported cannabis – wild cannabis has little THC.
By the 1970s, harvesting of wild cannabis was common in the US.
Led to chemical pesticide spraying by local governments.
1980s and the USWar on Drugs –
dope goes indoors
Greater US state and federal law enforcement campaigns.
After 1989, growers moved largely indoors – labs, hydroponics.
1996 - California became the first state to re-legalise marijuana for
medicinal use.
Indoor growing became the norm.
2012: Colorado and Washington state re-legalise adult use of
marijuana.
Both states focused on regulating - and privileging - energyguzzling indoor cultivation!
Australia’s cannabis history
As with the US, medicinal cannabis available in colonial Australia.
No data on extent of use.
Opium was seen as a much more dangerous drug of abuse and
traffic (racist associations with Chinese).
1938: the term ‘marihuana’ appears in Australia in connection with
the ‘reefer madness’ moral panic in the US.
Medical cannabis finally phased out in the 1960s in Australia.
Destruction of wild crops in 1970s.
Similar VietnamWar and counterculture influences in Australia.
Current
cannabis law in
Australia
ACT, 1977 –
Australian
Marijuana
Party
Legalisation – the high economy
Impact of legalisation of recreational and medicinal use in the US:
23 US states allow adult recreational use, 38 allow medical sales.
2020: legal sales = $17.5 billion, a 46% increase from 2019.
By comparison, craft beer industry in the US = $41 billion in annual sales.
Estimated creation of just over 6,000 new full-time jobs in retail and
production.
Also marketing, data analysts, lawyers, health professionals.
Reduction of cannabis-related criminal convictions – similar use rates,
but black people are 3.6 times more likely to be arrested for marijuana
possession compared to whites.
Legalise
Cannabis Party
- bill
20 June 2023 - bill introduced in state parliaments in Victoria, New
South Wales andWestern Australia.
Legalise Cannabis Party has representation in all three states’
upper houses.
Bill would allow adults to possess and grow small quantities of
cannabis at home.
Similar toACT model.
The bill is NOT currently supported by WA’s ALP government
(Roger Cook).
Legalisation – the high economy
Impact of legalisation of recreational and medicinal use in the US:
State and federal taxes, fair wages, infrastructure and regulation all cost
small business owners.
They can’t always make a profit.
California – very complex state laws: selling 500g for $3000 illegally, or
selling 500g for $600 legally?
Most cannabis trade still illegal.
Illicit cannabis sales estimated at $100 billion each year.
Both legal and illegal sellers use a mix of bricks-and-mortar, e-commerce
and ‘rideshare’ type delivery systems.
Legal traders rely on government to shut down illegal traders.
How it gets into the body
Inhaled as smoke: cannabinoids travel rapidly from the
lungs to the blood and brain.
This leads to higher levels of THC in blood plasma.
Ingested: absorbed from the intestines => liver where it is
metabolised (first-pass metabolism)
This leads to lower levels of THC in blood plasma.
Cannabinoid receptors
The two major identified cannabinoid receptors in the body are CB1 and
CB2
G-protein-coupled receptors (see eTute 1).
CB1
receptors: mostly CNS and peripheral NS.
CB2
receptors: mostly immune cells and spleen; also GI tract, skeletal
muscle, skin, cardiovascular system, reproductive system, liver.
CB2
receptor agonists [stimulate a response] are targets of emerging
research due to their potential analgesic, anti-inflammatory, and
immune-modulating properties.
https://www.azolifesciences.com/article/Comparison-of-ReceptorPharmacology-in-Cannabinoids.aspx
How is it
turned into
product?
Most cannabis produced and consumed in the world is herbal:
dried flowers and smallest leaves and stems of the female
cannabis plant.
sinsemilla (‘seedless’) crops: remove all male plants from field.
hashish (‘grass’) or resin: paste-like substance obtained by
compressing the resin glands (trichomes) of the female cannabis
plant.
bhang: edible paste-like cannabis, used in foods and drinks during
some Hindu and/or Sikh religious occasions.
butane hash oil (BHO): a solvent-extracted, cannabis
resin concentrate made with liquid butane.
rosin: solvent-less extract - heat and pressure with heating
hydraulic press.
edibles: gummies, tea, powders, butter/oil, brownies.
Pharmacodynamics
Cannabis is a polypharmaceutical substance (comprised of many
compounds, including cannabinoids).
Those of primary interest are:
Cannabidiol (CBD)
Tetra-hydro-cannabinol (THC)
Cannabinoid receptors are located throughout the body: brain,
major organs, connective tissues, glands, immune cells.
The human body has cannabinoid receptors …
… which means the human body has endocannabinoids!
anandamide - discovered and named in 1992
responsible for biological effects such as increasing appetite,
decreasing nausea, decreasing pain sensitivity, and providing
anti-inflammatory activity.
What goes
where?
All cannabinoids are not equal!
THC has equal affinity to both CB1 and CB2 (partial agonist).
Synthetic cannabinoids are “fussy” - highly selective agonists or
antagonists to one of the receptor types.
CBD does not directly affect either CB receptor (antagonist):
It modifies the receptors’ ability to bind endocannabinoids.
For example, CBD enhances the activity of anandamide.
CBD is thought to interact with several other receptors like the μreceptor and serotonin (5-HT) receptors.
How does THC
get you high?
Good question …
May cause short-term dopamine flooding (and long-term blunting of
dopamine effects).
THC seems to unplug the brain’s ‘default mode’ network (how we daydream
and think about past and future).
Psychedelics such as LSD and psilocybin seem to have a similar effect on the
brain’s ‘default mode’ network.
Difficulties in studying this phenomenon: illegality, subjective experience of
‘high’.
Pharmacokinetics -
smoking
This depends on:
The route of administration.
The cannabinoid involved.
The physical characteristics of the user.
Both THC and CBD are highly lipophilic -> they like to snuggle in your fat cells.
THC produces the ‘high’.
CBD acts without euphoric effects.
Bioavailability of inhaled THC is highly variable: between 10% and 35%.
The THC content also varies depending on how inhaled:
Doobs: less THC content partially due to pyrolysis at higher temperatures and
loss due to side smoke; more tar and impurities.
Vaping: highest content of THC and cleaner vapour.
Smoking effect can occur within seconds; can be fully apparent within minutes; lasts up
to 3 hours.
