Researchers have discovered the presence of cannabinoid receptors (CB2 receptors) in human sensory nerves. The findings may lead to a new class of pain medications that target the peripheral nerve system, while bypassing the deleterious effects of cannabis-like drugs on the brain. The study is published in the September 15 journal Pain, led by researchers from Imperial College London.
Past studies on pain treatment have focused on CB1 receptors, activated by cannabis. CB1 receptors are found in the brain. Though effective, the side effects associated with current pain treatment include drowsiness, dependence and, according to some studies, psychosis. CB1 receptors are also the target of other opiates, such as morphine, and those side effects range from nausea, vomiting, drowsiness, dependency, impaired bowel function, decreased appetite and even depression.
According to Praveen Anand, Professor of Clinical Neurology and Principal Investigator of the study from the Division of Neurosciences and Mental Health at Imperial College London, "Our new study is very promising because it suggests that we could alleviate pain by targeting the cannabinoid receptor CB2 without causing the kinds of side-effects we associate with people using cannabis itself."
The CB2 drugs are able to block the transmission of pain through nerve endings, showing much promise for osteoarthritis, neuropathy and acute pain following surgery and injuries. To reach their conclusions, the study team used sensory nerve cells in cultures, provided by GlaxoSmithKline, as well as damaged nerves from patients with chronic pain.
Dr. Anand points out that "Although cannabis is probably best known as an illegal recreational drug, people have used it for medicinal purposes for centuries. Queen Victoria used it in tea to help with her period pains, and people with a variety of conditions say that it helps alleviate their symptoms.”
The UK's first Academic Health Science Centre, The Imperial College Healthcare NHS Trust, has been integrated with the Imperial College London. Studies are planned there by Dr. Anand and his team to conduct further clinical trials of drugs that target CB2 receptors. This is the first time that the existence of CB2 receptors have been found in human sensory nerves. Should the researchers succeed in developing the drugs, pain control without the side effects associated with many pain medications will provide tremendous benefit to millions of chronic pain sufferers.
According to the National Institute of Neurological Disorders and Stroke, chronic pain is a persistent problem that differs from acute pain. Pain signals “keep firing in the nervous system for weeks, months, even years.” Sometimes there is no associated injury. Researchers are always looking for individuals with chronic pain, in efforts to find answers that can improve quality of life, and lead to a greater understanding regarding the mechanisms and treatment of chronic pain.
If you have a condition that causes pain on a daily basis, you may want to enroll in studies that can help. If so, please visit ClinicalTrials.gov.
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