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Psychoactive Plants


Psychoactive Plants Hallucinogens - I: Marijuana Marijuana Cannabis sativa is one of the oldest cultivated plants in the world Possibly used by humans for over 10,000 ... – PowerPoint PPT presentation

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Title: Psychoactive Plants

Psychoactive Plants
  • Hallucinogens - I Marijuana

  • Cannabis sativa is one of the oldest cultivated
    plants in the world
  • Possibly used by humans for over 10,000 yrs
  • Known by many names mary jane, hashish, hash,
    pot, grass, hemp, etc
  • Native to central Asia and widely used for
    thousands of years
  • As a hallucinogen
  • Medicinally
  • For fiber (rope, paper, fabric) - hemp
  • For oil and seeds

Early History of Marijuana
  • Long history of use in China (over 5000 yrs) as a
    medicinal plant
  • Scythians (nomadic tribe from central Asia) used
    it as a hallucinogen about 500 BC India maybe
  • Spread throughout Asia, Africa, and elsewhere
  • Became prominent in India for both medical and
    religious use (first written account in India
  • In Middle Ages widely used throughout Arab world
  • Most notorious story about marijuana is the
    fanatical Muslim sect known as Hashishins who
    swore to kill all Christian crusaders. Group name
    from hashish also gave rise to the word assassin

Later History
  • Use in Europe limited to fiber for many years
  • Said that Naploens army introduced the
    psychoactive use when they returned from campaign
    in North Africa/Egypt
  • By mid-19th century Paris Hashish had
    widespread use among artists and intellectuals
    who believed it enhanced their creative powers

History in North America
  • Marijuana was probably introduced to the United
    States around the turn of 20th century possibly
    from Mexico or the Caribbean Islands.
  • Mexican laborers brought the marijuana smoking
    habit with them when they immigrated.
  • In the 1920's it spread among the urban poor in
    the South but was not in vogue until jazz
    musicians popularized smoking marijuana
  • Not only was marijuana used recreationally, but
    it was also a popular ingredient in many
    over-the-counter medications.

US History
  • During the 1930's concerns about the dangers
    inherent in marijuana use led to the
    establishment of laws prohibiting its use.
  • The Federal Bureau of Narcotics launched an
    "educational campaign" to make the public aware
    of the dangers of marijuana use.
  • Campaign greatly distorted the problem and
    grossly exaggerated the dangers
  • Concerns culminated in the federal Marihuana Act
    of 1937 which controlled the legal sale of the
    plant and resulted in the virtual elimination of
    Cannabis from the nation's pharmacopoeia.

Recent History
  • The dramatic increase in marijuana use came about
  • Marijuana became the recreational drug of choice
  • In reaction to the pervasive usage of marijuana
    during the 1970's many communities relaxed their
    laws concerning personal use and possession
  • The public demand for decriminalization of
    marijuana usage peaked in the late 1970's and
    recent trends seem to be for stricter enforcement
    and harsher sentences for users and dealers

New Laws in England
  • In October 2001, England relaxed its marijuana
    laws, downgrading it from a class B to a class C
  • This means that marijuana still remains illegal
    but the maximum penalties for possession are
    greatly reduced
  • Also under the new law, the police will no longer
    able to arrest someone on the street for
  • Prosecutions will be carried out by court summons
  • The new law is expected to take effect in spring

Botany of Cannabis sativa
  • Dioecious annual with male and female flowers on
    different individuals
  • Distinctive compound leaf with seven leaflets
  • The hallucinogenic properties concentrated in the
    resin which is produced by glandular trichomes
  • Maximum amount of resin on female plants,
    especially unfertilized female flowers

(No Transcript)
Female Plant
Male Plant
  • Hallucinogenic properties concentrated in the
    resin with the compound Delta-9-tetrahydrocannabin
    ol (THC) the main psychoactive compound
  • THC belongs to a unique group of phenolic
    compounds called cannabinoids

  • Concentration of THC varies greatly with the
    variety, sex, climate, growing conditions
  • Sinsemilla varieties have highest THC
  • Varieties cultivated for fiber (hemp varieties)
    have the lowest levels of THC

THC Levels
  • The most potent varieties of Cannabis are usually
    grown under the hot dry conditions which seem to
    optimize THC production
  • As a result Marijuana grown in Mexico, Columbia,
    and India generally have higher "street value"
    because of its higher THC levels

Sensemilla varieties
  • Seedless strain developed illicitly in California
    during the 1970's thought to have the highest
    levels of THC
  • Hybrids result from crossing C. sativa and C.
    indica (a hardy species native to Afghanistan)
  • Cultivated by cloning pistillate plants in high
    tech indoor gardens - "Sea of Green"
  • Possible to bring about abundant flowering in two

Effects of Marijuana
  • Euphoria and calmness
  • Even moderate use impairs learning, short-term
    memory, and reaction time
  • THC is fat-soluble and accumulates in body
    tissues and may remain for days
  • One of the best studied effects is decreased
    sperm production
  • Decreased testosterone levels have also been

Cannabinoid Receptors
  • Humans have cannabinoid receptors in the brain,
    CNS, and other tissues
  • Functions of these receptors and the endogenous
    ligands unclear
  • At least two subtypes of these receptors exist -
    CB1 and CB2 - evidence also suggests other
  • G-protein linked receptors

Cannabinoid Receptors
  • CB1 cannabinoid receptors - most prominent in the
    brain and CNS and appears to mediate the
    psychoactive properties
  • CB2 cannabinoid receptors - appear to be almost
    exclusively expressed in the peripheral tissues -
    especially immune tissues and may modulate
    responses of the immune system

Natural Cannabinoids
  • First natural cannabinoid discovered in 1992
  • Anandamide is an endogenous ligand to the
    cannabinoid receptors in brain function so far
    has not been determined only moderate binding
    ability to CB1
  • Other natural ligands have since been identified
  • When activated, CB1 receptors seem to suppress
    the neuronal release of one or more transmitters
  • Show some interaction with opiate receptors

  • CB1 receptors are extremely abundant in the brain
    more so than most other G-protein linked
    receptors 10x more abundant that m opioid
    receptors (responsible for pain relief and
    euphoria from opiates)
  • Studied extensively in vertebrates and
    invertebrates highly conserved molecule
    suggesting a long evolutionary history (500
    million yrs) suggesting that cannabinoids play
    and important basic function in animal physiology

Medical Uses of Marijuana
  • Marijuana has been used as a medicinal plant by
    cultures throughout the world
  • In modern medicine, several well documented uses
  • glaucoma treatment
  • aid to chemotherapy
  • reduce tremors in MS patients
  • analgesic

Glaucoma Treatment
  • Glaucoma - eye disorder characterized by
    increased pressure
  • This can damage the optic nerve and lead to
  • Leading cause of blindness in the U.S.
  • Marijuana - either smoking or ingesting oral
    preparations can decrease ocular pressure - smoke
    is especially effective

Aid to Chemotherapy
  • Chemotherapy for cancer often has side effects
    that result in nausea, vomiting, and loss of
    appetite - often results in severe weight loss -
    patients weaken considerable - often impairing
  • Marijuana helps offset some of these effects -
    and especially increase appetite

Multiple Sclerosis
  • Multiple sclerosis causes the destruction of
    patches of myelin in the brain and spinal cord
  • Demyelination produces many problems, so that
    victims eventually cannot walk, sit up, and
    become crippled and bedridden often with terrible
    muscle spasms

Treatment of MS
  • No effective treatment for MS
  • Medications provide some relief from muscle
    spasms however, the drugs lead to addiction
  • Marijuana reduce spasms in patients with MS
  • Individuals using marijuana have testified that
    sight and walking have been regained and spasms
    reduced or eliminated,
  • There is some evidence that the progress of MS is
    actually retarded

  • AZT and other drugs used to treat AIDS result in
    nausea and anorexia
  • Like use of chemotherapy in cancer patients, this
    commonly causes severe weight loss which impairs
    the bodies ability to fight
  • Marijuana helps nausea and increases the appetite
    thereby counteracting weight loss

Analgesic Effects
  • In animal tests cannabinoids are analgesic and
    reduce neuropathic pain
  • Likely similar action in humans
  • Studies show that cannabinoids are no more
    effective than codeine and have enough side
    effects to limit their use
  • Further studies needed to see about use for
    spasticity and neuropathic pain

New Laws
  • Since 1996, eight states (Alaska, California,
    Colorado, Hawaii, Maine, Nevada, Oregon, and
    Washington) have enacted laws or passed referenda
    that effectively allow patients to use medical
  • These laws permit patients to use marijuana on
    the advise of their physicians.
  • In addition Arizona passed legislation, which
    allows physicians to write prescriptions for
    medical marijuana use

States with effective medical marijuana laws
Note Arizona has a law but it is not effective
because it only permits medical marijuana use
when it is prescribed but physicians cannot
legally prescribe
Federal Response
  • In response to these laws, the federal government
    initially threatened to prosecute any physician
    that prescribed marijuana to patients
  • This produced an uproar in the medical community
  • The American Medical Association indicated that
    physicians should be free to discuss any option
    that might help their patients and recommended
    new studies on medical uses of marijuana

Editorial in NEJM
  • It was wrong to prohibit physicians from helping
    their patients.
  • It called for the reclassification of marijuana
    as a Schedule II drug so that physicians could
    prescribe it when needed.
  • Marijuana is currently classified as a Schedule I
    drug which is defined as a drug with no accepted
    medical use and a high potential for abuse.
  • Schedule II drugs can be prescribed for
    appropriate medical applications

Marijuana and Medicine
  • In January 1997, the White House Office of
    National Drug Control Policy (ONDCP) asked the
    Institute of Medicine of the National Academy of
    Science to conduct a review of the scientific
    evidence to assess the potential health benefits
    and risks of marijuana and its constituent
  • That review began in August 1997 and culminates
    with 1999 book Marijuana and Medicine Assessing
    the Science

Conclusions of NAS Study
  • Cannabinoids likely have a natural role in pain
    modulation, control of movement, and memory.
  • The natural role of cannabinoids in immune
    systems is likely multi-faceted and remains
  • The brain develops tolerance to cannabinoids.
  • Animal research demonstrates the potential for
    dependence, but this potential is observed under
    a narrower range of conditions than with
    benzodiazepines, opiates, cocaine, or nicotine.
  • Withdrawal symptoms can be observed in animals
    but appear to be mild compared to opiates or
    benzodiazepines, such as diazepam (Valium).

Supreme Court
  • In May 2001 the U.S. Supreme Court unanimously
    ruled that medical use of marijuana is not a
    valid exception to the federal law that
    classifies marijuana as an illegal substance.
  • Writing for the court, Justice Clarence Thomas
    wrote that the controlled substance statue
    "includes no exception at all for any medical use
    of marijuana."

Supreme Court
  • Although voting with the majority, three justices
    (John Paul Stevens, David Souter, and Ruth Bader
    Ginsburg) wrote a concurring opinion stating that
    the decision went too far.
  • They believe that there should have been a
    medical necessity option for a patient, "for whom
    there is no alternative means of avoiding
    starvation or extraordinary suffering."