Harmless replacement of narcotic analgesics

Painkillers acting on cannabinoid receptors and non-addictive have been discovered

Anna Stavina, XX2 century, based on Indiana University Bloomington: IU study suggests potential chronic pain treatment without opioid or medical marijuana side effects

Neuroscientists from Indiana University in Bloomington have discovered that cannabinoid receptors in the brain can be used to combat chronic pain syndromes without the risk of developing undesirable effects characteristic of opioid painkillers or medical marijuana.

"The most important aspect of this study is the potential achievement of the therapeutic effect characteristic of opioid painkillers, without the risk of addiction or the formation of resistance to therapy," said Andrea Hohmann, professor in the Department of Psychological Sciences and Brain Studies of the College of Arts and Sciences Indiana University in Bloomington.

Millions of people around the world suffer from chronic pain syndromes. The active use of opioid analgesics for the treatment of chronic pain has contributed to the development of the epidemic of opioid addiction in the United States. In 2014, 19 thousand deaths related to the abuse of medical opioids were registered in the country. In Indiana, the repeated use of needles and syringes to administer these drugs has led to a large-scale HIV outbreak in the southeast of the state.

"The number of deaths related to the abuse of medical opioids has already exceeded the combined number of deaths from cocaine and heroin overdoses. This fact was largely the impetus for the study of cannabinoids as an alternative means of combating chronic pain syndrome," said Richard Slivicki, a graduate student from the Homann laboratory, who led the study. "This serious epidemiological crisis has created the motivation for our work."

During the study, it was found that compounds controlling the activity of brain receptors for tetrahydrocannabinol and endogenous cannabinoids are able to reduce the severity of chronic pain in mice. Tetrahydrocannabinol is the main psychoactive component of marijuana, and endogenous cannabinoids are natural painkillers produced by the brain.

The compounds whose work the researchers studied were called positive allosteric modulators or PAM (positive allosteric modulator, PAM). Their effect is based on the ability to attach to the CB1 site recently discovered on the surface of the brain's cannabinoid receptors. Tetrahydrocannabinol attaches to another site of the same receptors. Positive allosteric modulators were synthesized by study co-author Ganesh Thakur from Northeastern University.

Researchers from Indiana University in Bloomington studied the effects of PAM attached to the CB1 site on neuropathic pain. This type of pain develops in approximately 40% of cancer patients as a side effect of chemotherapy. Scientists injected experimental mice with paclitaxel, a chemotherapeutic drug known for its ability to damage nerves and cause pain. The mice then received PAM-based treatment.

After the introduction of paclitaxel, the mice became extremely sensitive to mechanical irritation of the paws and to the effects of cold on them, which indicated the appearance of pain. After the introduction of PAM, the mice began to behave as usual, from which the scientists concluded that the pain syndrome disappeared.

In the course of the study, it was also found that PAMs attached to the CB1 site enhance the positive effects of endogenous cannabinoids, without leading to the development of "marijuana intoxication", which can manifest itself, for example, in impaired motor functions. PAM was used in combination with a substance that suppresses the process of splitting endogenous cannabinoids and thereby increases their level in the body.

The scientists also managed to establish that the effectiveness of PAM in terms of pain relief did not decrease over time, while tetrahydrocannabinol and cannabinoid cleavage inhibitors stopped working after several doses.

"We have determined that PAMs do not create pleasant sensations by themselves, so they are unlikely to be used for recreational purposes," Homann added. "Our study has shown that we can achieve such therapeutic efficacy, which we have not observed with the use of certain types of analgesics used in clinical practice."

Portal "Eternal youth" http://vechnayamolodost.ru  28.11.2016