Overcoming Pain

Why people experience chronic pain, and the power they have to de-intensify it

Reefer Redux: Update on Medicinal Marijuana

One harvest the pilgrims didn't have.
In a prior post, the benefits and risks (from both the criminal and clinical viewpoints) of therapeutic marijuana (cannabis, to the scientists) were discussed. Marijuana's euphoric effects seem to have relegated it, in the minds of the representatives of the judicial branch of this country, to the status of something solely for those pain sufferers who have difficulty with reality.

But that may be changing.

In a report in a recent issue of the journal "Pain", research appears to be showing that some cannabis-like drugs can relieve pain without affecting the brain. Such drugs bind to only one of the two cannabinoid receptors that are activated by cannabis. The medical benefits of cannabis are captured, while the adverse effects are avoided.

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Cannabis activates the CB1 cannabinoid receptors in the brain and the peripheral nervous system; it also activates the CB2 receptors, which are present only in the peripheral nervous system. Past research had focused chiefly on the CB1 receptors, as scientists had hypothesized that this was the receptor most responsible for pain relief. In other words, if a patient wanted to use marijuana to get rid of that nagging pain, expect that patient to also get high.

Now, however, scientists have discovered that CB2 receptors are also important for pain relief. It follows that, because the CB2 receptors are present in the sensory nerves in the peripheral nervous system, and NOT in the normal human brain, drugs which activate the CB2 receptors should be able to alleviate pain without affecting those parts of the brain which can lead to dependence and drug abuse.

The conclusion in the recent article discussed above was based upon the examination of human tissue from a variety of subjects, including persons who had suffered no injuries as well as those who had sustained severe trauma. It was found that CB2 is expressed in the part of the nerve cell called the dorsal root ganglion, and actually increased in concentration after painful injury. When an agent that had a positive affinity to the CB2 receptor was introduced to nerve cells grown in the laboratory, the nerve cells stopped firing.

Further, agents with a positive affinity for the CB2 receptor inhibited pain in the sensory nerve cells via a mechanism similar to that seen when opioid drugs are used. It would follow that this opens up the possibility for the development of medications which target the CB2 receptor, providing an alternative to, say, morphine-and in turn avoiding the dependency, nausea and vomiting seen with morphine.

One can see many potential research projects for improving the lot of those who suffer acute and chronic pain.

For those chronic pain sufferers who actually enjoy some of the adverse effects of medicinal marijuana, you have plenty of time: research is still at an early stage when it comes to clear-thinking cannabis.

In the meantime, put the headphones on and break out the Beatles albums. You know, the ones that told us Paul was dead and what recreational drug to use. Everybody smoke pot, right?

Mark Borigini, M.D., is a board-certified rheumatologist who has devoted his career to treating illnesses that cause chronic pain and disability.

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