A wakefulness molecule is abundant in the brains of heroin addicts

June 27, 2018

Researchers have discovered that the brains of heroin addicts harbor a greater number of neurons that produce hypocretin, a molecule involved in arousal and wakefulness, and one lacking in abundance in people with narcolepsy. In mice with narcolepsy, these researchers went on to show, administering morphine - an opioid similar to heroin - reversed the symptom of cataplexy (loss of muscle tone), suggesting that altering hypocretin levels could potentially serve as a therapeutic strategy for treating narcolepsy. Narcolepsy is a condition affecting approximately 200,000 people in the U.S., and is characterized by excessive daytime sleepiness and cataplexy. Although scientists have developed treatments to address sleepiness and cataplexy, they do not restore normal function and can have unpleasant side effects. In previous studies, Thomas Thannickal and other researchers had found that narcolepsy was linked to a loss of hypocretin-producing neurons in the brain. Interestingly, they also noticed that the brain of a heroin addict enrolled in the study harbored more neurons producing hypocretin compared to other brains. Here, Thannickal and colleagues built on their previous work and investigated whether an abundance of hypocretin-producing neurons was characteristic of other opiate addicts. They studied postmortem brain tissue from four heroin addicts and found their brains exhibited an average 54% increase in hypocretin neurons compared to controls. Long-term administration of morphine to mice resulted in a similar increase in hypocretin neurons, an effect that persisted several weeks after morphine administration was halted. Turning back to narcolepsy, the authors found that administering morphine to narcoleptic mice deficient in hypocretin neurons restored hypocretin cell numbers and ameliorated cataplexy symptoms. Thannickal et al. say that future human trials should determine whether opiates or better yet, novel opiate-like compounds, could be used to restore hypocretin levels and treat narcoleptic patients. They also say that future research should investigate whether decreasing hypocretin levels could combat opiate addiction in humans.

American Association for the Advancement of Science

Related Neurons Articles from Brightsurf:

Paying attention to the neurons behind our alertness
The neurons of layer 6 - the deepest layer of the cortex - were examined by researchers from the Okinawa Institute of Science and Technology Graduate University to uncover how they react to sensory stimulation in different behavioral states.

Trying to listen to the signal from neurons
Toyohashi University of Technology has developed a coaxial cable-inspired needle-electrode.

A mechanical way to stimulate neurons
Magnetic nanodiscs can be activated by an external magnetic field, providing a research tool for studying neural responses.

Extraordinary regeneration of neurons in zebrafish
Biologists from the University of Bayreuth have discovered a uniquely rapid form of regeneration in injured neurons and their function in the central nervous system of zebrafish.

Dopamine neurons mull over your options
Researchers at the University of Tsukuba have found that dopamine neurons in the brain can represent the decision-making process when making economic choices.

Neurons thrive even when malnourished
When animal, insect or human embryos grow in a malnourished environment, their developing nervous systems get first pick of any available nutrients so that new neurons can be made.

The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.

Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.

How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.

A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.

Read More: Neurons News and Neurons Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.