Plants used for the nervous system and pain relief

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)

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

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

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

Endorphins Sometimes called the body’s

natural opiates Morphine, codeine, heroin and

other opiates mimic endorphins and bind to the same receptors in brain

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

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

An even shorter list Willow bark and others (salicylic

acid – aspirin) Poppy (morphine and codeine) Chili peppers (capsaicin) Marijuana (THC) Ergot (ergotamine) Others

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

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)

Salicylic acid

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

Acetylsalicylic acid

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

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

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

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

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

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

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