Researchers have successfully tested a new molecule that is more effective against pain than morphine in rodents, without its side effects.
The results are particularly encouraging, even if it is necessary to remain measured. Researchers at Stanford University (California) have developed a new molecule called PZM21, with powerful analgesic properties. In fact, the molecule is even more powerful than an opioid drug, with very limited side effects, according to the authors who publish their work in the journal. Nature.
More than three million molecules have been screened on a computer to obtain the formula for PZM21, the researchers explain. The tests were carried out on rodents, which constitutes the first major limitation of this study. Nevertheless, the results remain surprising.
Only one receiver activated
In these mice, PZM21 was shown to be as effective against pain as opiates, with much longer analgesic action. Another advantage: the molecule did not induce an addictive effect on rodents, which did not need weaning. Finally, PZM21 does not cause the side effects of opiates (nausea, constipation, drowsiness, even respiratory arrest, etc.), which is remarkable in a context where this drug class is wreaking havoc – particularly in the United States.
In fact, the country is facing an epidemic of overdoses linked to the misuse of opiates. In some states, this excessive consumption has even become the main cause of death among young people, ahead of road accidents. The authors therefore see in PZM21 the perfect opportunity to put an end to this scourge, while considerably enriching the therapeutic arsenal against pain.
In detail, PZM21 targets only one of the three opiate receptors, called “mu” (μ). The fact of not activating the other opioid receptors, delta (δ) and kappa (κ), precisely makes it possible to limit the side effects… But not necessarily to eliminate them. “Activation of the μ receptor alone can still cause respiratory depression”, points out Professor Alain Serrie, head of the Pain Medicine department at Lariboisière hospital.
Uncertain results
In addition, it will take years before developing such a molecule, which will have to undergo a battery of toxicology and efficacy tests on other animals (monkeys, dogs, etc.), before being tested on humans. . And yet, nothing proves that PZM21 will have on our species the effects observed on rodents, whose receptors are very far from ours.
Alain Serrie remembers having participated in the trials on antiankephalinases, which were to allow analgesics to have a longer action. On the rat, the tests were particularly conclusive. “But on humans, not at all,” recalls the doctor. In the end, the molecule ended up being marketed, not to treat pain but intestinal transit disorders … which shows that we must be careful not to go too quickly in our conclusions! “
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