Effects of Cannabis on Alzheimer's Disease investigated in mice

Some effects of Cannabis can improve the consumption of energy by the brain, which is deficient in Alzheimer's Disease, according to the results of a study led by Cellular Neurosciences and Biology Center (CNC), University of Coimbra (UC), Portugal and the Cajal Institute - Centre for Biomedical Research in Neurodegenerative Diseases, in Spain.

The future challenge  of this discovery in mice, recently published in the journal Neuropharmacology, lies in the separation of negative and positive effects of Cannabis consumption.

CB1 and CB2 receptors

The major psychoactive ingredient of marijuana, tetrahydrocannabinol (THC) acts on two receptors, "CB1" and "CB2", located in the brain, which are distinguished as "bad police and good police." The CB1 receptors are associated with neuronal death, mental disorders and addiction to various drugs or alcohol. In contrast, CB2 receptors nullify many of the negative actions of CB1, protecting neurons by promoting glucose consumption (energy) by the brain and reducing dependence on drugs.

Attila Köfalvi, first author of the article, explains that "through various laboratory techniques, we conclude that the CB2 receptor, when stimulated by chemically modified THC analogues to interact only with the CB2 receptor without activating the CB1, avoiding the psychotropic effects and keeping beneficial effects, promotes increased glucose uptake in the brain."

Effect beyond neurons

Additional experiments with other techniques showed that this effect of CB2 is not limited to neurons but extends to other brain cells that help the functioning of neurons, the astrocytes. "In the future, this discovery could pave the way for a palliative therapy in Alzheimer's disease," notes the researcher.

The international team enjoys the collaboration of the Brain Mapping CAI Multidisciplinary Institute of the Complutense University of Madrid, the Madrid Institute of Technology and Biochemical Research Institute of the National University Bahia Blanca del Sur in Argentina.

The research was funded by the Award Belard Santa Casa da Misericordia, DARPA, ERDF, NSRF - Regional Operational Programme 2007-2013 Centre with the support of Mais Centro and the European Union and Operational Programme Competitiveness Factors via the Foundation for Science and Technology .

Coimbra, May 23, 2016

Cristina Pinto

University of Coimbra

Originally published in the Portuguese version of Pravda.Ru

Translated by Ekaterina Santos

Portuguese version


Editor's note

Cannabis: The facts

The cannabis plant is called Cannabis sativa. Its main active ingredient is delta-9 tetrahydro-cannabinol (THC) and its potency depends on the strength of its range of products. There are three forms of cannabis, namely Marijuana (made from dried leaves and flowers, being the least potent). It is smoked in hand-made cigarettes (joints) or consumed in edibles; Hashish (made from the resin of the plant and condensed into blocks and crumbled into joints, often together with tobacco. It can also be eaten); Oil (Hash oil is a thick substance obtained from the resin and is smoked. It is the strongest form of cannabis).

The discussion

The recent annual meeting of AAAS, which publishes Science magazine, discussed the issue of public use of cannabis and sparked off a heated debate in many countries as to whether to legalize use of the plant, as has been done in Uruguay and certain States in the USA. The conclusions of the debate were published in February's issue of Science magazine.

To start with, cannabis has been around human beings for at least 5,000 years. And the question is, why do we know so little about it? The article in Science magazine (*) states that we know that there are 104 cannabinoids which react with the areas of our brains which are involved in the sensation of pain, mood, memory and appetite... yet the pharmacology of most of these 104 cannabinoids remains to be studied.

We do know that use of cannabis can reduce nausea and vomiting, and so it is useful to treat side-effects of treatments such as chemotherapy in cancer patients, and we do know that the use of the drug Sativex, manufactured using the psychoactive ingredient in cannabis called THC and cannabidiol (CBD), a non-psychoactive cannabinoid, can help patients suffering from multiple sclerosis.

There are some studies which indicate some promising results in the treatment of anxiety, depression, post-traumatic stress disorder, epilepsy and neuropathic pain... but here the trail leads us into a vast plain of unanswered questions, no clear confirmation in clinical trials and an absence of scientific evidence to draw up guidelines.

So five thousand years later, we are left with a handful of mainly younger members of society claiming it is cool to smoke weed and a disapproving Establishment which considers them as potheads or druggies who are well on the way to intravenous drug use.

Where we are today is like a crossroads with claim and counter-claim being made. Some data links the use of marijuana to an increased risk of schizophrenia. Other studies state that the link cannot be substantiated. Some studies indicate that heavy use of marijuana among teenagers with developing brains leads to lower IQ ratios, while others claim that the bases for such a statement have no foundations whatsoever. Some claim that brain scans show alterations after use of marijuana, others claim that the use of alcohol produces far more marked effects.

Recently, it was claimed in the UK that use of skunk cannabis, a powerful synthetic form of the drug, will cause psychosis in 25 per cent of the users, and the Lancet Psychiatry Journal recently published a paper claiming that strong forms of cannabis can lead to serious mental illness. But there are sceptics who claim once again that far more research needs to be done to reach any conclusions.

Governments are not even united on where they stand: in the UK cannabis is a Class B drug, in the USA it is a Schedule I drug (a dangerous substance with no medical benefit). In Russia, like in many countries, cannabis is illegal but decriminalized for personal use, for transportation or cultivation in small quantities but it is a criminal activity to sell. In Uruguay and the Democratic People's Republic of Korea, it is legal in all four categories.

Timothy Bancroft-Hinchey


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Author`s name Timothy Bancroft-Hinchey