1. Neuroscience

How hormones may alleviate side-specific movement difficulties after brain injury

Study reveals that hormones may produce different effects on the left and right-hand sides of the body and shows how these actions contribute to movement impairments following brain injury.
Press Pack
  • Views 73
  • Annotations

Hormones released after a brain injury contribute to movement problems on the left and right sides of the body, shows a study in rats published today in eLife.

The results also suggest that hormone-blocking treatments may help counteract these effects, a finding that has implications for treating people with traumatic brain injuries or stroke.

A stroke or injury to one side of the brain causes movement difficulties on the opposite side of the body. Scientists have previously thought that this is because nerves from one side of the brain control activity on the opposite side. But recent studies have shown that giving rats without a brain injury certain hormones can cause movement responses similar to human motor deficits on one side of the body. “This led us to ask whether pituitary hormones might mediate in part the side-specific movement problems humans can experience after brain injury,” explains Georgy Bakalkin, Professor at the Department of Pharmaceutical Biosciences, Uppsala University, Sweden, and a co-senior author of the study.

To investigate further, Bakalkin and the team examined the effects of a one-sided brain injury in rats that lacked the connection between the brain and nerves that regulate the hindlimbs. They found that, even without this connection, the hindlimb on the opposite side to the injury had impaired reflexes.

However, animals that lacked the pituitary gland, a hormone-producing gland connected to the brain, did not experience these problems. Two pituitary hormones ß-endorphin and Arg-vasopressin appeared to play a role. The team then gave rats without a brain injury these two hormones and found that they also developed hindlimb contraction on the right side.

Next, they tested what would happen if they gave the rats with a left-sided brain injury drugs that block the effects of these two hormones. They found that the animals did not develop right-sided movement problems. This suggests that the hormones convey side-specific signals after a brain injury and treating patients who have a similar injury with drugs that block the effects of these hormones might be beneficial.

“These observations suggest that the endocrine system through hormones in the blood may selectively target the left and right sides of the animals’ bodies,” Bakalkin concludes. “This is an unusual phenomenon that requires verification in other animal models. We must be cautious in the interpretation of these findings and their biological implications before further research is carried out. But if future studies confirm the benefits of treatments that block these hormones, they may offer a new approach to treating movement problems following stroke or injury.”

The study has been performed by an international team of investigators including the laboratory of Professor Alexander Tonevitsky, Dean of Faculty of Biology and Biotechnology at the National Research University Higher School of Economics, Russia. “This is an exciting line of research, and this study opens multiple possibilities for further collaboration that may result in development of conceptually novel pharmacological treatment of motor deficits secondary to stroke and brain trauma – the leading causes of permanent disabilities nowadays,” says Professor Tonevitsky.

Georgy Bakalkin (Uppsala University, Sweden) and Jens Schouenborg (Lund University, Sweden) are co-senior authors of the study. The team also includes co-first authors Nikolay Lukoyanov (University of Porto, Portugal), Hiroyuki Watanabe (Uppsala University), Liliana Carvalho (University of Porto), and Olga Nosova and Daniil Sarkisyan (both Uppsala University), as well as Mengliang Zhang and Marlene Storm Andersen (University of Southern Denmark), Elena A. Lukoyanova (University of Porto), Vladimir Galatenko (Lomonosov Moscow State University, Russia), Alex Tonevitsky (National Research University Higher School of Economics, Russia), and Igor Bazov and Tatiana Iakovleva (both Uppsala University).

Media contacts

  1. Emily Packer
    eLife
    e.packer@elifesciences.org
    +441223855373

About

eLife is a non-profit organisation created by funders and led by researchers. Our mission is to accelerate discovery by operating a platform for research communication that encourages and recognises the most responsible behaviours. We aim to publish work of the highest standards and importance in all areas of biology and medicine, including Neuroscience, while exploring creative new ways to improve how research is assessed and published. eLife receives financial support and strategic guidance from the Howard Hughes Medical Institute, the Knut and Alice Wallenberg Foundation, the Max Planck Society and Wellcome. Learn more at https://elifesciences.org/about.

To read the latest Neuroscience research published in eLife, visit https://elifesciences.org/subjects/neuroscience.