The abridged version:
Chemically speaking, we are all potheads. ... Numerous experiments with genetically altered mice and rats have shown that when natural brain compounds, called endocannabinoids, are missing or their receptors are blocked, the animals are more susceptible to pain, cannot control their appetites, have trouble handling anxiety and are less able to cope with stress.
By fully understanding and then harnessing the endocannabinoid mechanisms, researchers are eager to devise new ways to reduce pain, calm anxiety, fight obesity, stop nicotine addiction and even treat traumatic shock and Parkinson's disease-without the unwanted side effects of smoking marijuana.
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To be precise, endocannabinoids do not mimic the effects of marijuana. It is the drug, derived from the hemp plant, that approximates the brain's endocannabinoid chemistry.
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CB1 receptors are not everywhere in the brain