Senior rats treated with THC show improved learning and memory tests
Think of the stereotypical smoker: young, nonsensical, and confused. Marijuana has long been known for its psychoactive effects and can include cognitive impairment. The new research post in Nature Medicine shows that the drug affects adults more than children.
As in adolescence, rather than impair learning and memory, the drug effect appears to reverse the age-related decline in cognitive function in adult rats. Bonn and Andreas Zimmer of the University of Germany gave marijuana to young, mature, and adult rats. THC, the main active compound of Delta-9 tetrahydrocannabinol. As expected, young rats treated with THC had slightly worse memory and behavioral test learning.
For example, after receiving THC, young rats had more time to know where the water was hiding in a safe platform, and they had difficulty identifying another mouse that had previously been exposed. Drug-free, mature, and aged rats performed worse on tests than young children. But after giving THC to adult animals, their activity was similar to that of young, untreated rats. “The resonance is powerful and very deep,” says Zimmer.
This well-designed series of experiments demonstrates that chronic THC pretreatment restores significant cognitive performance in older rats and confirms the opposite effect in young rats,” wrote external research director Susan Weiss. The study was not related to the National Institute on Drug Abuse by email.
When researchers examined the brains of adult rats, they found that the hippocampus, which is a crucial brain area for learning and memory, has a more synaptic spine in the hippocampus, contact points for communication between neurons. Most notably, the gene expression pattern of hippocampi in THC-treated aged rats was radically different from that in untreated adult rats. “It was something we never expected. Older animals receiving THC are similar to untreated young control rats,” says Zimmer.
These findings raise the curious fact that THC and other “cannabinoids” act as brain antigen molecules. Cannabinoids include dozens of biologically effective compounds found in the cannabis plant. Plant compounds mimic the marijuana molecule, called endogenous cannabinoids, in our brain, which activates specific receptors in the brain that can regulate nerve function. “We know that the endocrine cannabinoid system is very dynamic. Says Ryan McLaughlin, a researcher who studies cannabis and stress at Washington State University and is not involved in the current work.
Research shows that the cannabinoid system gradually develops during childhood. “It explodes into adolescence. You see, it increases the activity of its enzymes and receptors,” says McLaughlin. It is gradually decreasing as we age. “
The decline of the endocrine cannabinoid system with aging is consistent with previous work by Zimmer et al. Cannabinoid-related molecules are found in the brains of aged animals. “As animals get older, the endocrine cannabinoid system, like humans, slows down, and it coincides with the signs of aging in the brain,” says Zimmer. “So we thought, what if cannabinoids are stimulated by the system? “”
According to Mark Weir, a clinical researcher at McGill University, this idea is “absurd” when Maintaining the body’s natural balance of cannabinoids. “For anyone who studies the endocannabinoid system, the findings are not surprising, because the system has homeostatic properties everywhere we look,” which means that its effects can vary depending on the situation.
For example, marijuana can alleviate a little anxiety, but it can also cause a lot of confusion. Similarly, cannabis can cause appetite in patients and cause nausea in other people. Thus, the adverse effects seen in young brains, where cannabinoids are already abundant, may be beneficial for those with age related brain deficits.
McLaughlin says these chemicals also help maintain cellular levels. The primary function of the endocrine cannabinoid system is to try to preserve homeostasis in a given brain circuit. It acts as an internal regulator; During the heavy activity, cannabinoids suppress activity to prevent neurotoxicity. “Restoring that protection helps protect the brain from the cellular stress that contributes to aging. “A crucial step in this study is low-dose use,” Ware said, noting that different doses can have completely different effects. It is difficult and impossible for rats to transform their dose into humans: “But we don’t talk too much. We don’t know what happens at higher doses.”
Science does not know exactly how marijuana affects older adults. This is because they are more focused on teens who think they are at higher risk. “When it comes to public health, research has focused on the effects of marijuana on adolescents. But despite the high prevalence of cannabis use among young people, drug use is increasingly available, and their use rates have remained relatively stable over the past decade.
Meanwhile, as the stigma of drug use has declined, the use of seniors has increased. Between 2006 and 2013, people aged 50 to 64 increased cannabis use by 60 percent, according to a March study. Drug usage amongst adults over the age of 65 has increased by 250%.
Researchers suggest that seniors should start using cannabis soon. “I don’t want to promote anyone to use cannabis-based on this research,” says Zimmer.
Older adults who take medical cannabis to treat chronic pain and other illnesses are concerned about its side effects. Ware says: “They want to know. Does this hurt my brain?” Does it hurt my memory? If this data exists in humans, it implies that if you use the right dose, [THC] will not have a negative effect. It is now a challenge for clinical researchers to study it in humans. “