Cannabis

Why the interest in cannabis?

-Most commonly cultivated, trafficked, and abused illicit drug worldwide

-Annual consumption rate ~147 million individuals (~2.5%) of global population

-Medical use

-Increased knowledge of endocannabinoid system

Legal status

-Canada legalized cannabis in 2018 for both medicinal and recreational use

-2nd country in the world to fully legalize it

-Still illegal in many countries (for medical included)

Cannabinoids

-Broad class of chemical compounds named for those found in the cannabis plant and stored within the plant’s trichomes

-Cannabinoids in the body are endocannabinoids

-Cannaninoids in plants are phytocannabinoids

Two primary cannabinoids

Tetrahydrocannabinol(THC) and cannabidiol (CBD)

History (part 1 – Ancient)

-Used for thousands of years medicinally, recreationally, and for industrial purposes

-10,000 years ago: cannabis fibers (hemp) used to produce textiles, paper, ropes, etc.

-5,000 years ago: Medicinal use in China

-Pharmacopedia: Flowers of female plant provide most medicinal value; warned that “ingestion of too many cannabis seeds will produce visions of the devil” – first doceumentation of cannabis’ psychoactive properties

-c1600 BC cannabis use in India for anticonvulsant, hypnotic, anti-inflammatory

History (part 2 – West)

-Ancient Egyptians used it to treat glaucoma, inflammation, etc.

-1800’s Cannabis introduced in West for medicinal purposes

-1830’s: Irish doctor Dr. O’Shaughnessy studying in India found cannabis helped lessen stomach pain and vomiting in people with cholera

Medicinal use in U.S

-Used as patent medicine during 19th and early 20th century

-First used around 1850s as medicine

-Too high dose can cause bad reactions in some - made doctor overly cautious, resulting in cannabis to not have intended effects (trial and error like prescriptions)

History in US (part 1 up to 1950s)

-1910’s: States began to prohibit cannabis

-1937: Federal restrictions of its use and cannabis sales due to Marihuana Tax Act

-Tax act made cannabis get removed from Pharmacopoeia in 1942

-Legal penalties for possession increased in 1951 and1956 because of enactment of Boggs and Narcotics Control Acts

-These legislations led to limitations on research by limiting procurement of cannabis for academic purposes

History US (part 2 – 1970s to present)

-1970: Controlled Substance Act made canabis schedule I drug with “no accepted medical use”

-1990s: Researchers discover cannabinoid receptor system

-2018: “Farm Bill” legalized hemp

-Hemp: Anything from cannabis plant that’s less than 0.3% concentration of delta-9 THC

THC isomers

Delta 9, delta 8 (not as potent as 9), delta 10

-Farm bill mentions specifically delta 9 THC since its most abundant and has most psychoactive effects

-Therefore, delta 9 is illegal but not the other isomers in the US! Canada’s law was more broad so consuming delta-8 above the legal limit is illegal in Canada but not the US

History Canada

-1923: Cannabis classified as illicit substance

-2001: Medical cannabis legalised

-2018a: Consumption and sale of recreational cannabis legalized (Bill C-45)

-2018b: Criminal code of Canada was used to allow pilice to use roadside saliva tests for drugs including THC; introduced per se limits for THC (Bill C-46)

-2019: Edibles, extracts, and topicals were legalized

-Until late 60s cannabis use wasn't a major issue

Common forms of cannabis:

-Flower (marijuana): dried flowers and leaves; most common form in North America

-Kief: Powdered from ground up plant material (more concentrated and has higher THC content)

-Hashish: Compressed resin (more common in Europe)

-Tinctures: Alcohol based cannabis extracts

-Concentrates: Highly concentrated cannabis extracts

-Cannabutter: Popular type of cannabis infusion

Common ways to use cannabis

Smoking, vaping, edibles, topicals (more for medicinal)

Potency changes

-Past 2 decades has show significant increase in THC concentrations

-Marijuana cigarettes: 60s and 70s: 1-3% THC; 80s and 90s: avg 6% THC; 2000s: avg 17% THC

-Hash oil: 2008 7% THC; 2017 56% THC

Strains of cannabis plants

-Cannabis sativa (formally described in 1753)

-Cannabis indica (discovered in 1785)

-Cannabis ruderalis (used for textiles, concentrations too low for medicinal or recreational)

Hemp vs Marijuana

-Marijuana: Any cannabis plant that has greater than 0.3% THC

-Hemp: Cannabis plant that has 0.3% or less THC

Plant comparison

Cannabis indica:

-Origin: Mountainous regions of Central Asia and India

-Characteristics: Size (short, bushier; 3-6 ft tall), leaves (broad, thick leaves), growth cycle (grows faster with shorter flowering period)

-Believed to be physically sedating, perfect for relaxing, reducing anxiety

Cannabis sativa

-Origin: Southeast Asia, Central and South America, and Africa

-Characteristics: Size (taller, slender; 6-12 ft tall), leaves (narrow, long), growth cycle (longer growing season and flowering period)

-Believed to be invigorating, cause uplifting effects that pair well with physical activity, social gathering, and creative projects

Hybrids

-Thought to fall somewhere in between, offering indica and sativa effects; most plants these days are hybrids

Activation of cannabinoids

-Cannabinoids created by plant from carboxylic acid: delta-9 and cannabidiolic acid (CBDA)

-Neutral cannabinoids formed (decarboxylation process) during exposure to light, heat, or as a result of prolonged stored: delta 9 THC, CBD

Trichomes

-Glandular structure

-10 to 100 micrometers

-Shiny, sticky crystals, giving buds their frosty appearance

-Trichomes are defensive mechanism

-Contains highest concentration of cannabinoids and terpenes

-Trichomes appear on plant when it enters flowering stage, just before buds enter harvesting period (can determine peak time to get highest THC concentration)

Terpenes

Aromatic compounds commonly produced by plants and fruit

Most common terpenes in cannabis

Myrcene, pinene, limonene, linalool, beta-caryophyllene

Entourage effect

-Some compounds can enhance or alter THC’s psychoactive and medicinal properties

-Ratio of THC to CBD and various terpenes could be important (ex: just extracting CBD could be negating some positive effects of THC)

Concentrates

-Removes all excess plant material

-High concentrations of THC

-Becoming very popular

Why extracts?

-Necessary to purify and concentrate compounds of interest from plant

-Remove impurities

-Activate the chemicals
-Decarboxylation needs to occur to remove the acid precursors

Extraction techniques

-Rosin press

-Dry-sieve extraction

-Water extraction (solvent-less)

-Ethanol extraction

-Supercritical fluid extractions (SFE) using liquid CO2

-Solvent extraction (butane, propane)

Rosin press

-Producing rosin requires heat, pressure, time

-Instrument is bought just to extract this; hair straighteners have been used for this purpose too lol

Water extraction

-Bubble hash: solventless concentrate that is extracted using water → popular since it preserves the terpenes for enhanced flavour

-Ice makes trichomes brittle

-Ice and marijuana buds are agitated together and THC gets extracted through micron screens

Butane Hash Oil (BHO)

-BHO made by blasting cannabis with butane → butanes solvent makes THC become soluble, resulting in a butane/THC mixture

-Butane evaporated and the resulting product is an amber coloured resin e.g. “wax”

-Can be quite dangerous

Shatter

-Very stable and a concentrated extract of cannabis

-Very hard and brittle; breaks easily if you drop it (unlike hash oil which is sticky/budder and waxy)

-Once butane is evaporated, shatter producers often apply gentle heat to the concentrate, often in a vacuum chamber to remove the terpenes as they evaporate

Live resin

-Flash freezing freshly-harvested plant at temperatures below -180 C

-Labelled as “full plant” or “full spectrum” due to it involving the entire plant (flowers, leaves, branches, stalk)

-Preserves terpene profile of plant

THCA diamonds

-THC acidic form

-Called diamond mining

-Special way to extract cannabis extracts

-Crystals formed over time and not decarboxylated so its active

Diamond mining

-Highly specialized technique to isolate potent cannabis concentrates

-Involves separation of THCA crystals from cannabis extracts

-THCA crystals are pure, non-psychoactive compounds until decarboxylated

Diamond mining process

-Resin placed in container and left to separate for 2-3 weeks

-Cannabinoid crystals start to form on bottom of container as the solids separate from the terpenes, forming a semi-viscous liquid layer on top

-The resulting diamonds often contain 95-98% pure THCA

Diamond mining benefits

-High potency: Can reach over 99% purity

-Flavourful: Terpene-rich sauce adds distinctive flavour profile

-Versatile: Can be consumed as concentrates, dabbed, or added to other cannabis products

Cannabinoids mechanism of action

-Highly lipophilic

-Acts via G-proteins

-Discovery of high-affinity binding sites for cannabinoid molecules (discovered cannabinoid receptors)

Research milestones

-1964: delta 9 THC is primary psychoactive component of cannabis

-1988: CB1 receptor identified

-1990: CB1 receptor cloned from rat

-1991: CB1 receptor cloned from human

-1993: CB2 receptor identified

Location of cannabinoid receptors

-CB1 receptor found in CNS and other tissues, systems, and organs (liver, reproductive system, cardiovascular system, skeletal system, GI tract, etc.)

-CB2 occurs in immune system and other tissues (bones, adipose, GI tract, etc.)

-Concentration of cannabinoid receptors in brain stem is low → may be why cannabis isn’t associated with sudden death due to respiration depression

CB1 receptors

-G protein linked receptors

-Most abundant G-protein pinked receptors in brain

-Localization of CB1 receptors suggests primary function of them is to inhibit neurotransmitter release

CB1 receptor effects

-Inhibition of cAMP

-Inhibition of voltage sensitive Ca2+ channels

-Activation of K+ channel opening

-All the effects above lead to powerful inhibitory effects on neurotransmitter release (inhibits Ach, DA, NE, 5HT, GABA, glutamate)

Research focus and milestones (part 2)

-CB receptors initiated research for endogenous cannabinoid ligands

-1992: Identification of first endocannabinoid: N-arachidonylethanolamine (anandamide – sanskrit for “internal bliss”)

-1995: Identification of second endocannabinoid: 2-arachidonoylglycerol (2-AG)

Mechanism of action of endogenous cannabinoids

-2-AG is a full agonist at CB1 and CB2

-Anandamide is a partial agonist → won’t get max response (THC and CBD are also partial agonists)

-Endocannabinoids are probably removed from the extracellular fluid by membrane transporter

-Anandamaide: metabolized by fatty acid amide hydrolase (FAAH)

-2-AG: metabolized by monoacyl-glycerol lipase (MAGL)

Endocannabinoid system (general)

-Most complicated and most abundant signaling system in out bodies

-Goal to maintain homeostasis despite fluctuations in the external environment

Endocannabinoid system – three key components

-Cannabinoid receptors (found on surface of cells)

-Endocannabinoids: Small molecules that activate CB receptors

-Metabolic enzymes: Breaks down endocannabinoids after they’re used

Pathways cannabinoids regulate

GI activity, cardiovascular activity, pain perception, maintaining bone mass, neuroprotection, hormonal regulation and metabolism control, immune function, inflammatory reactions, inhibition of

Endocannabinoids vs other neuromodulators

-Unlike other neuromodulators, they aren’t synthesized in advance and stored in vesicles

-Have precursors that exist in cell membranes and are cleaved by specific enzymes

-”On-demand” synthesis

Rimonabant

-CB1 receptor agonist

-Anti-obesity drug used in Europe in 2006

-Suppresses apetite and reduces craving for sweet foods

-BUT induces symptoms of anxiety and depression → led to its removal as a medicinal treatment

Fear conditioning tasks

-Rimonabant or gene knockout impaired extinction of fear response when tone is presented alone

-Rimonabant group exhibited more freezing behaviour during fear extinction compared to vehicle

Implications for PTSD

-Cannabinoid agonist drug could help

-Compounds that block endocannabinoid metabolism or uptake could help

Appetite

-Endocannabinoids have. asigniicant role in hunger, eating behaviour, and energy metabolism

-CB1 antagonist decreases food intake; use of rimonabant to treat obesity has adverse side effects

Subjective effects of endocannabinoids

-”High” associated with euphoria and exhilaration and sense of disinhibition

-Relaxation most commonly reported effect of being “stoned” – floating sensations, enhanced visual and auditory perception, visual hallucinations, slowing of time passage

Physical effects of endocannabinoids

-Increased blood flow to skin

-Increased heart rate

-Increased hunger

-Mediated by CB1 receptors – effects are significantly reduced by pretreatment with rimonabant

Pain

-Knockout mice (CB1 and CB2 Rs) or mice treated with rimonabant have hyperalgesia

-CB1 and CB2 receptors participate in regulating pain perception and cognitive-affective responses to pain

ECS and Aggression

-Cannabis associated with relaxation but can also cause anxiety and paranoia

-THC only partial agonist at CB1 receptors

-Synthetic cannabinoids tend to be full agonists → have induced extreme violent and aggressive behaviours

-Animal studies: Low doses of THC have reduced frequency of attacks by resident animals in a dose-dependent manner

Pharmacokinetics of THC

Absorption → distribution → elimination

Absorption – smoking

-Principle route of cannais administration

-Characterized by rapid absorption of THC

-Concentration depends on amny factprs: #, duration, spacing of inhalations, inhalation volume

-THC can be measured in blood within seconds after first inhalation

-Peak effects while smoking but its effects persist hours after finishing smoking

Absorption – ingestion

-Sower absorption following oral route with a lower and delayed peak THC concentration

-Peak occurs 1-3 hours after administration

-Edibles are opposite → quite lipophilic so it increases absorption rate since it absorbs lipids, fats, etc.

Distribution

-THC has large volume of distribution 10L/kg

-97-99% protein bound in plasma

-Highly perfuse organs rapidly exposed to the drug

-THC is highly lipid soluble which results in concentration of THC and its retention in fat → stored in fatty tissue for a while

-Slow release of THC from fat contributes to its long half-life (up to 4 days in chronic users; can be detected weeks if they took a lot)

Elimination

-THC metabolized to another active substance 11-OH-THC

-Concentrations of 11-OH-THC are typically 10% of THC concentration

-Major inactive metabolite is carboxytetrahydrocannabinol or THC-COOH → this one found in urine tests

-Mean plasma concentration of THC and metabolites: THC peaks immediately while smoking then plummets (150 to <20, then 0); 11-OH-THC stays very low (~5 to 0), THC-COOH is moderately high and stays fairly consistent (~40 to 50)

Absorption of THC

-Easily absorbed by lungs; blood plasma levels rise quickly

-Concentrations begin to decline as result of liver metabolism and accumulation in body fat

-Oral use: Poor absorption results in low and variable plasma levels, probably due to degradation in stomach and first-pass metabolism

THC detection

-21 chronic cannabis users used cannabis then gave blood, urine, and oral fluid (saliva) samples for 7 days where the abstained from cannabis use

-Blood THC detectable for up to 7 days after admission

-Urinary THC-COOH exceeded 1000 ng/mL for some subjects 129 hours after last use

Oral fluid THC detection

-THC doesn’t excrete well into oral fluid (since its lipophilic)

-THC commonly consumed via smoking or oral ingestion of edibles

-THC can be found in saliva due to oral contamination (edibles)

-Residual deposits in oral cavity could lead to individuals having oral fluid concentrations exceeding cut-offs for short periods of time

Physiological pharmacodynamics of THC

Increased heart rate, reddening of eyes, dry mouth, increased appetite, vasodilation

Cognitive effects

-Memory impairments during acute exposure

-Acute exposure: deficits in verbal learning, attention, working memory, inhibitory control, and psychomotor function

-Chronic: All the above (excluding inhibitory control) and impaired executive function

-Age you use CB matters as well

Edibles

-Subjective drug and cognitive performance effects generally dose-dependent

-Peak at 1.5-3 hours post-administration, lasted for 6-8 hours

Passive inhalation of THC

-Passive inhalation resulted in positive results for THC-COOH but is always below typical cutoff (no matter how much smoke)

-Only trace amounts

Postmortem changes of THC concentration

-Significant levels of postmortem THC concentration changes have been observed

Interpretation of all possible THC results

-Blood to plasma concentration ratio: 0.55

-Urine positive result = prior exposure (not use since passive exposure is possible)

-Oral positive result = recent drug use (halve concentration for blood equivalent bc of blood to plasma ratio)

-Lots of limitations to THC interpretations: no comments on route of administration, amount taken, when taken, and impairing effects

Long term supervision order (LTSO)

-Noncustodial sentencing option available to the courts to extend the length of time that the Correctional Service of Canada (CSC) will supervise and support an offender

-LTSO starts when sentence is served and cannot extend 10 years

-Intended for managing offenders who pose significant risk to re-offend if not effectively supervised

-Often required to abstain from alcohol or other intoxicating substances or the consumption of drugs (exceptions being medical prescriptions)

-Positive test results → courts want to know if the accused consumed drugs while under the LTSO

Civil cases (workplace fatalities)

-Linking impairment due to cannabis to a blood concentration of THC

-Recency of cannabis could indicate potential impairment

-When did the worker consume cannabis? Were they impaired

Cannabis sommelier role

-Involves olfactory and gustatory processes of cannabis

-Focuses on science and safety

-Focus on quality

Does high THC % = high quality?

No, THC % measures potency, not quality

Language depending on context

-Context depends on what word you use: botanical, industry, consumers/community

-Ex: Sticky, icky, crystal, and trichome are all the same thing

Hemp plant name

Cannabaceae

Sex of cannabis plant

-Dioecious (separate male and female plants)

-Can also be hermaphrodite (produces both male and female gametes; self-pollinates if it might die and hasn’t reproduced)

Female plant

-Lower quality cannabis if female plant creates a seed → uses energy to make seed rather than trichomes

-Has V structure shape called pistils or stigma (pollen goes through pistil or stigma)

Cola

-Flowering top of cannabis plant

-What people smoke

Fan leaves

-Responsible for photosynthesis (the bigger, stereotypical cannabis leaf)

Sugar leaves

-Closer to plant than fan leaves

-More protective function because they are sticky and covered in trichomes

Pistil

-Pistil is part of the reproductive organ of the plant (looks like red-orange hairs)

-Pistil catches pollen for creating seeds and procreation

Calyx

-Shell where the reproductive resources are in

-Is a platform made of small leaves (called sepals) to protect flower bud

-First thing that forms once your cannabis plant enters the flowering stage

-Responsible for growing pistils and trichomes

Stem and node

-Stem: Main structure of a plant that supports the plant

-Node: Where leaves branch off from the stem

Trichomes

-Tiny, hair-like outgrowths that cover cannabis and hemp flower

-Creates terpenes and cannabinoids

-On leaves and calyxes

Cannabigerol (CBG)

-Cannabinoids begins as Momma CBG; the “Momma cannabinoid”

-Broken down into other cannabinoids

-CBG breaks down into THC or CBD, etc.

Acidic vs neutral forms of cannabinoids

-Acidic: Non-active forms of cannabinoids (THCA, CBDA)

-When exposed to heat, it becomes its active

-Neutral form: Active form of cannabinoids

Flavonoids

-Gives plants, flowers, fruits, and vegetables their colours

-Ex: Anthocyanin produces the purple in eggplants and cannabis

Terpenes

-The smells and tastes of cannabis

-Protect plants from fungus, environment stressors, etc.

-Terpenes and flavourants together create the taste of cannabis

Quality testing of cannabis

-Overall appearance: Bud shape, bud integrity,

-Trim: High quality is no sugar leaves, no sharp/jagged leaves or stems

-Colour: Dark green, purple, and blue (high quality) vs yellow and brown (low quality)

-Moisture: Sponginess or brittle

-Aroma

-Trichome quality: Clear (not at full potential) → turn cloudy (mature; cannabinoid expressed at full potential) → amber (overly mature; altered by age) → mixed (cannabinoids transitioning in content)

-Contaminants

-Taste test (joint used bc its the least forgiving)

Microdosing

-Microscopic dose of products to gage experience before having a full dose (ex: one inhalation of a joint or 2mg of an edible)

Titration

-Start small and take incremental, microscopic steps upward until you hit that sweet spot

Modalities of ingestion

• Inhaled: lungs → bloodstream → brain

  • Effects/onset (3-10 min)

  • Duration (20-80 min)

• Ingestion/edibles: Chewed and goes to stomach to get broken down → goes to liver → liver converts THC to 11-hydroxy-THC (3-5x more potent than inhaled THC)

  • Onset: Very delayed (bc of the metabolism) hence why it hits harder and longer

  • Duration: 1-6 hours

• Sublingual:

  • Onset: (10-20 min)

  • Duration (60-120 min)

Dabbing

-A method of consuming cannabis in a concentrated form

-Only for very experience cannabis users

-Uses small amount of rosin

-You put it in a weird, heat-resistant glass pot and heat up a section of it heating up thing that's made up of heat-resistant glass

-You heat it up, and you inhale these vapours

-Extremely potent, it makes a small amount of resin have strong effects

-It's one of the healthiest ways to consume cannabis – but its extremely potent so you must be careful

-If you heat it up at a lower temp, the terpenes are burnt at a slower rate so the flavour lasts longer (but you do risk not using it all up

Over ingestion of cannabis

-No lethal overdose

-Managing over ingestion: Drink citrus water, remove stimulations, sleep it off or exercise, hydration, tell yourself its ok you’re just really high lol

Cannabis extract types

• Rosin: Applying heat and pressure to raw cannabis flower creates the concentrate rosin

• Hash (using the ice mesh water method will create a hash rosin)

• Keith

• Most extracts can be dabbed except hash and keith (they’re the simplest extracts to produce but the least pure bc there’s plant matter attached → it’ll start a fire)

  • Must be trichomes w/ no plant matter

Top 3 listed reasons for medical use of cannabis

-Pain relief

-Depression

-Anxiety

Cannabis for mental health

-Commonly used to alleviate anxiety, stress, and depression

-~70% daily cannabis users report relaxation and stress reduction is main reason of use

Anxiety

-Ppl who report using cannabis to cope with anxiety frequently use it to help with social anxiety disorder

-THC lowers anxiety at lower doses and increases it at higher doses

-CBD decreases anxiety (no anxiogenic effects at higher doses)

-Risk factors of cannabis-induced anxiety: individual and genetic vulnerability, high dose, high THC/low CBD, history of anxiety, environment and context use

-THC and some CB1 receptor agonists are known to induce biphasic (low vs high dose) effects

-CB1 receptors present in glutameteric and GABAergic transmission could play role in different effects of cannabinoids on anxiety

Social anxiety disorder and cannabis study

-37 adolescents who are cannabis naive and have SAD for 6+ months

-Daily 300mg CBD (no THC or terpenes) or placebo

-Underwent Fear of Negative Evaluation Questionnaire (FNE); post-treatment CBD group exhibited significant decreases in FNE scores

Rimonabant (focus on anxiety)

-Inverse agonist at CB1 receptor

-Anxiogenic at high doses → so severe it was taken off the market

-Evidence that CB receptors involved in mental health

Elevated plus maze studies

-Useful for assessing anxiolytic and anxiogenic effects

-Research question #1: Does CBD effect anxiety-related behaviour in rats?

• CBD 2.5, 5, and 10 mg/kg entry ratio (open/total number of entries)

• Diazepam (a benzodiazepine) used as positive control

• Higher CBD dose of 20 mg/kg had no effect (no anxiogenic effect) → no negative or positive benefits at high doses

-Research question #2: Does THC effect anxiety related behaviour in rats?

• Low doses decrease anxiety

• High doses induce anxiety

Basal condition

-Equilibrium btwn excitatory and inhibitory transmission provides an appropriate emotional reactivity