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Opium Poppy
Opium Poppy: Papaver somniferum
Member of the Papaveraceae, poppy family
Large showy annual with conspicuous flowers (white, pink, red, purple)
Fruit is a capsule that produces latex with several potent alkaloids
Latex is collected from cut capsules (latex oozes out and dries – dried latex scraped off) - dried latex called opium
Fresh capsule of opium poppy
Cut capsule showing latex exuding from cut
Opium Poppy Native to the Mediterranean area Oldest evidence of poppy use was
existence of a poppy capsule found with religious artifacts from a cave in Spain that are dated 7500 years old
Evidence of spread in Europe from 3000 to 5000 years ago
Reasons for use at these sites unknown
Ancient medical use Poppy was revered by several ancient
societies for its analgesic properties and its ability to induce sleep
Opium latex has a long history of use for pain relieve and inducing sleep among Babylonia, Egyptian, Greek, and Roman civilizations Opium eaten, drunk, and smoked Most common method was to dissolve opium in
alcohol – opium wine
Mediterranean societies Writings of Hippocrates, Theophrastus,
Dioscorides, and Galen show evidence of the widespread use of opium
In eastern Mediterranean it seems that poppy also became valued for its narcotic use
Ancient goddess of Crete is depicted wearing a crown with 3 poppy capsules
Opium Alkaloids Many alkaloids have been identified in
opium latex (opiates) - maybe as many as 50
Morphine and codeine most important Morphine first alkaloid identified from any
plant in 1806 and the pain relieving properties soon recognized
Morphine (like raw opium) is strongly addictive and because of this its general medical use declined in 20th century
Still drug of choice for cases of severe pain
Morphine Morphine affects the central nervous
system but also induces drowsiness and can depress respiration - overdose can cause death through respiratory failure
Cause has high physical dependency Has relatively low oral activity Became drug of choice to treat war
injuries during Civil War - created many addicts
Codeine Codeine most widely used opiate Only 1/5 as strong as morphine and
still addictive Effective in oral medication and
often used in combination with non-opiate compounds
Codeine is especially effective in cough syrups because it suppresses the coughing reflex
Heroin In 1898, Bayer Pharmaceuticals
introduced heroin which they thought was a non-addictive opiate and more effective than morphine and codeine
Heroin is a semi-synthetic derivative of morphine - diacetyl morphine
Widely available in over the counter tonics and cough syrups from 1898 to 1914 - mail order catalogs, etc
Heroin Within a few years over 1 million people
addicted to heroin in US alone Soon realized that it was actually more
addictive than morphine - actually six times more addictive
In US use of heroin is illegal placed under Harrison Act of 1914
Heroin still used medicinally in other countries
Heroin addiction a major problem worldwide
Isoquinoline alkaloids
Opiates
Mode of action Opiates bind to opiate receptors in
membrane of neurons of the brain and spinal column (ID’d in 1970s)
The natural ligands that normally bind to these receptors are endorphins and enkephalins (small peptides)
These peptides are released at synapses on neurons involved in transmitting pain signals to the brain
Opiate receptors When enkephalins bind to the opiate
receptors they inhibit neurons from transmitting pain signal - pain signal does not reach brain
Inhibit release of neurotransmitter “Substance P”
Substance P used by the sensory neurons involved in the perception of chronic and/or intense pain
Opiate receptors Peptides and receptors form a
complex neurotransmitter system that plays a major role in controlling pain, euphoria, and motivation
Also involved in other biological events - stress responses, immune regulation, respiration, endocrine responses
Different classes of opiate receptors
Opiate receptors Three (or 4) classes of opiate receptors -
with subtypes of each Opioids exert their effects by activating
one or more of these receptors Pain relief involves activation of one
type receptors in the brain and another in the spinal cord
Other receptors are are involved in respiratory depression and euphoria
Opiate receptors (mu) receptors - analgesia, euphoria (kappa) receptors - sedation, spinal
cord analgesia (delta) receptors - Antitussive
(coughing) properties, emesis (vomiting), and anticholinergic (constipation)
sigma (?) receptors cardiac stimulation
Opiates Morphine and the other opiates
bind these same receptors Morphine especially binds to
receptors Explains why opiates are excellent
pain killers However, they are also highly
addictive