Cannabinoids: a new frontier for the treatment of Parkinson´s disease

The first evidences about the use of cannabis arise from the second millennium BC, when Assyrians used cannabis or, as they called it, “the drug that takes away the mind” for its psychoactive, mind-altering effects and for its medical properties. Since it was brought to the western world in the 18^th century, its use has been a source of controversy. Surprisingly, research on cannabis has advanced slowly. The major reason was the lack of knowledge about its basic chemistry. Unlike morphine and cocaine, which were isolated and used for research since the 19^th century,  the chemical structures of the psychoactive constituents of cannabis were not isolated until the 1960s. There are over 400 chemicals in cannabis, 80 of them unique to this plant. The exact chemical composition differs between plant species, the parts of the plant and growing conditions. Once the chemistry of the plant was elucidated and the psychoactive molecules identified, it was possible to find the bases of the endocannabinoid system, which is particularly relevant to functions associated with the central nervous system such as pain, mood or apetite. The elements of the endocannabinoid system are highly expressed in brain structures related to movement control, suggesting that they could also be involved in movement disorders such as Parkinson’s disease.

Unravelling the evolution of the human brain

There is no doubt that one of the big scientific challenges ahead is to understand how brain activity is translated into specific mental states. If we are to solve this question, we must first obtain a deeper knowledge of the outer layer of the brain, made up of billions of neurons, which is known as the neocortex. The neocortex is organized into functional areas associated with movement, perception and with higher cognitive abilities typical of humans. In Homo sapiens, the neocortex amounts roughly to 80% of the total mass of the brain, an evolutionary leap compared to other primates and even great apes. How was such innovation achieved?