1. Plants used for the nervous system and pain relief

2. What is the nervous system?
Composed of billions of neurons that function by conducting impulses
Coordinates functioning of all body systems
Major parts of the nervous system
Central nervous system (brain and spinal cord)
Peripheral nervous system (sensory and motor systems)

3. Neurotransmitters
Chemicals that transmit nervous impulses from one neuron to the next
There are over 25 different neurotransmitters known. Common ones include:
Serotonin
Epinephrine
Dopamine
Acetylcholine
Norepinephrine
Some plant compounds mimic neurotransmitters or interfere with their normal function
Levels of neurotransmitters in brain can alter mood and perception and impact thinking and learning

4. Pain Pain is detected by a class of neurons called nociceptors
Different nociceptors respond to heat, pressure, or chemicals released from damaged or inflamed tissue
Prostaglandins increase pain by sensitizing the receptors (lowers threshold)
Chronic pain affects 97 million people in US and costs about $100 billion/year

6. Endorphins
Endorphins are polypeptides that act as chemical painkillers
Produced naturally in the body
Able to bind to the receptors in the brain to give relief from pain
responsible for the so called runner's high,
loss of pain when severe injury occurs
analgesic effects of acupuncture
released into the brain during laughter

7. Endorphins Sometimes called the body’s natural opiates
Morphine, codeine, heroin and other opiates mimic endorphins and bind to the same receptors in brain

8. Plants and Pain
Plants have been popular sources of pain remedies in just about every culture on earth
Plants boiled and/or beaten and ground into teas, pastes, poultices, and ointments to ease the pain

9. A short list of plants
Willow bark, comfrey leaves, coriander, sage, and sarsaparilla root were common old world remedies
Sweet birch bark, cinchona bark, and hot peppers were common plant remedies used by people in the new world
Banana and aloe plants also fought pain, as compounds found in their leaves and stems were used to soothe burns and blisters

10. An even shorter list Willow bark and others (salicylic acid – aspirin)
Poppy (morphine and codeine)
Chili peppers (capsaicin)
Marijuana (THC)
Ergot (ergotamine)
Others

11. Aspirin: willow bark to Bayer
Most widely used synthetic drug but origins are botanical
Bark of willow trees (Salix spp.) used by many cultures for reducing fever and relieving pain - in form of a tea
Old world ancient Greece
New world - Native American tribes

12. Path to a synthetic
In 1828 salicin was first isolated and over the next decade the extraction method was refined
Salicin is a glycoside of salicylic acid
Salicylates occur widely in species of Salix as well as many other plants including meadowsweet (Spirea ulmaria)

13. Salicylic acid

14. Next step
Laboratory synthesis of salicylic acid in the mid-19th century
Salicylic acid was an inexpensive treatment for many ailments - rheumatic fever, gout, arthritis
Had side effects - especially gastric
In 1898 Felix Hoffman, a chemist at Bayer Company came across acetylsalicylic acid

15. Acetylsalicylic acid

16. Acetylsalicylic acid Effective and more palatable
Soon given the name aspirin
"a" is from the acetylsalicylic acid and the
"spirin" from Spirea the plant from which salicylic acid was first isolated

17. Physiological action Three classic properties
anti-inflammatory
antipyretic (fever reducing)
analgesic (pain relieving)
New uses in the prevention of heart attacks, strokes, and colon cancer
Drawbacks:
irritates the stomach
Reye's syndrome

18. Mode of action
Key to understanding some of the action of aspirin was discovery by British researcher John Vane
Looking at role of aspirin and heart attacks
Vane showed that low doses of aspirin suppressed the aggregation of blood platelets which is necessary for blood clots
Blood clots can block blood vessels and lead to heart attacks

19. Prostaglandins
Mechanism is suppression by way of effects on prostaglandins
Prostaglandins are hormone-like substances that regulate numerous other activities in the body
influence the elasticity of blood vessels
direct the functioning of blood platelets that controls blood flow
cause redness and fever

20. Prostaglandins Prostaglandins are released from injured cells
Also released from cells stimulated by other hormones
Over production of prostaglandins can lead to headaches, fever, menstrual cramps, inflammation, blood clots, etc

21. Salicylic Acid in Plants
Since initial discover identified in many plants
Now believed that salicylic acid is a naturally occurring plant hormone involved in many reactions including plant protection
Plants respond to attack by a host of defenses - many already discussed
Plants also respond with a broad based defense mechanism known as Systemic Acquired Resistance

22. Systemic Acquired Resistance
Helps plant protect against secondary infections
Salicylic acid is signal that turns on SAR
SAR turns on synthesis of specific proteins that increase resistance
External application of salycylic acid will turn on response
Will also turn on responses in nearby plants by conversion to volatile methyl salicylic acid