Monday, December 12, 2011

Your Personal Narcotic

     All human beings (and probably all mammals) use 'narcotics' on a daily basis. We are not all drug abusers. We are not all drug addicts. The 'narcotics' that we use are our own, made by our bodies (endogenous) for normal daily function.
The Pituitary Gland and Hypothalamus

     These endogenous narcotics are called endorphins and are produced by the pituitary gland (at the base of the brain) and by the hypothalamus (a deep brain structure). These 'morphine-like' substances are released when we are excited, when we are in pain, when we are in love, during orgasm and even during exercise. Release of endorphins provides the body with a sense of well-being and can dull pain that could otherwise be disabling.
    Endorphins are neurotransmitters (see post: The Genetics of Drug Addiction) and the most important endorphin (or at least the one most studied) is called 'ß-endorphin'. The importance of this particular endorphin comes from the fact that it reacts mostly with specific receptors on the nerve cell (called μ1-opioid receptors). These μ1-opioid receptors are the same receptors that narcotics such as morphine react with. When ß-endorphin (or morphine) attaches to the μ1, certain neurotransmitters are blocked (GABA) and others are enhanced. The enhancement is especially pronounced with dopamine, the 'brain-reward' transmitter (see post: The Genetics of  Drug Addiction).
The Runner's 'High'

     The pleasure or 'brain reward' experienced with endorphin or morphine stimulation at these μ1 receptor sites, leads to the desire and 'need' to seek out this same stimulus - endorphin release from a 'runner's high' or (often intravenous) narcotic administration. When narcotic abuse is the case, these μ1 receptors are essentially 'high-jacked', triggering dopamine release and creating dependency.
     But why do human beings have this 'natural morphine' release? What use could it be or could it have been in the past? One theory to explain this phenomenon is based on the statistics of running speed and endurance. Animals, such as human beings, are not fast runners but do have the ability to run for long distances.

Masai Hunters
     In prehistoric times, catching a fast-moving meal may have been impossible for these relatively slow-moving humans but eventually, if chased far enough and for a long enough period of time, the meal-to-be would tire, slow down and fall into the hands of the pursuer. 
     Endorphin release in the man chasing the prey enabled the hunter to ignore the pains of twists and bumps, the aches of exhaustion and reach his goal. This may explain why some of the best long-distance runners in the world originate from regions where long distance hunts are common and have been for thousands of years.

Isolation/Flotation Tank
     Certain studies have suggested that endorphin release also occurs when floating in 'isolation/flotation tanks' as well as during acupuncture.

     The placenta secretes endorphins during pregnancy into the mother's blood stream. Why this occurs is unclear but some suggest that this ß-endorphin production creates dependency in the mother and forces her metabolism to direct nutrients to the growing fetus (the child addicts the mother!).

Acupuncture and Endorphin Release

     Post-partum depression may therefore be a type of 'narcotic withdrawal' that sometimes can be countered by the mother's own endorphin release when breast-feeding.
Placental Secretion of Endorphins

     The 'runner's high' is probably not entirely due to these morphine-like substances our bodies produce. There are many other natural chemicals that have been suggested as important in feeling the euphoria of victory or extreme exertion and in dulling the pain of a severe injury.

     Naturally occurring cannabinoids (endocannabinoids) such as anandamide are thought to play such a role.
     Other neurotransmitters such as epinephrine, serotonin and dopamine (that wonderful reward neurotransmitter) have also been shown to be important.

      * The genetics of drug addiction: subject of research for the novel Whip the Dogs -Amazon Kindle

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