July 4, 2000 Web posted at: 2:03 PM EDT (1803 GMT)July 4, 2000 Web posted at: 2:03 PM EDT (1803 GMT)LONDON (Reuters) -- British scientists are closer than ever to developing drugs based on cannabis that will take away pain -- but also take away the "high."
Researchers from Imperial College in London have separated cannabinoids, the active components of the popular recreational drug, and shown that they act on both the brain and spinal cord.
The findings will allow scientists to develop cannabinoid-based drugs designed to target the spinal cord to relieve pain, but bypass the brain to prevent the often euphoric high associated with using cannabis.
"We have achieved a really important step in terms of divorcing the psychoactive side effects of cannabis from their pain-relieving effects," Dr Andrew Rice told Reuters.
"What we've done is to identify the fact that there are receptors for the cannabinoids in the pain areas of the spinal cord," he said.
In their research, scientists used receptors for cannabinoids on the spinal cord, particularly the areas concerned with pain processing.
By delivering drugs directly to the spinal cord to relieve pain they bypass the brain so there are no psychoactive effects.
New drugs based on cannabis are still years away but the findings, published in the journal Molecular and Cellular Neuroscience, are an important first step.
Rice and his colleagues said cannabinoid-based drugs would be more effective than opioid analgesics, such as morphine, for pain caused by spinal cord injuries and nerve damage.
"When you injure a nerve you lose the opioid receptors in the spinal cord. That is why morphine does not work well in those situations," said Rice.
"What we have shown in this paper is that when you injure the nerve the cannabinoid receptors stay," he said.
The British researchers followed a similar course to the development of morphine-like drugs in the 1970s. The epidural drug delivery system, commonly used to relieve the pain of childbirth and for chronic and cancer pain, was developed after scientists discovered its receptors on the spinal cord.
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Cannabis could be source for new drugs
WebPosted Tue Jul 4 15:21:09 2000
LONDON-- Scientists may soon find a way to use cannabis to development drugs that ease pain without the "high."
Researchers have separated cannabinoids, the protein responsible for the psychoactive properties of the popular drug, and found that they act on both the brain and the spinal cord.
The report, published in the journal Molecular and Cellular Neuroscience, says the findings may lead to cannabinoid-based drugs designed purely for pain relief.
"We can either develop drugs based on cannabinoids acting on spinal receptors that don't have the psychoactive side effects," said Dr. Rice, who authored the report. "Or we can deliver the cannabinoids to the spinal cord site of pain relief without involving the brain."
The process is expected to work because it mimics the process that led to the development of the epidural drug delivery system, commonly used for pain caused by childbirth and cancer. But new drugs are still years away.
Cannabinoid-based drugs would be used to relieve neuropathic chronic pain (caused by damaged nerves). Current opioid analgesic drugs, such as morphine, are ineffective because the opioid receptors in the spine disappear when the nerves are damaged. Unlike opioid receptors, spinal cannabinoid receptors remain, giving researchers good reason to be optimistic about developing better drugs.
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