Such a system could become an alternative to animal models in research and contribute to the development of new non-opioid painkillers that do not cause addiction.

Scientists from Stanford University in California, USA, for the first time managed to create a synthetic neural circuit in the laboratory that mimics the path of pain signals from the skin to the cerebral cortex, reports msn.

This development could significantly accelerate the emergence of new treatments for chronic pain.

The research team was led by Romanian scientist Sergiu Paşca, who in 2017 introduced the concept of assembloids into science. Assembloids are a combination of two or more organoids - spherical cell structures or cultured cells, combined to reproduce the structural and functional properties of an organ.

Paşca's group used stem cells obtained from human skin to grow four types of nervous tissue organoids. Among them were both sensory neurons of the skin and neurons of the cerebral cortex. These four organoids were grown separately and then combined in one vessel. After about 100 days, they fused into a single assembloid about 1 cm long. This model had about 4 million cells and demonstrated synchronized electrical activity between all segments.

To test the functionality of the created neural network, the researchers used capsaicin, a substance that makes chili peppers hot. After its application, a powerful reaction immediately appeared in the assembloid: waves of electrical signals instantly spread from the "skin" to the "brain".

Sergio Pasca emphasizes that this model does not feel pain in the usual sense, but only imitates the transmission of signals that in a living organism go deeper into the brain, where the emotional component of pain is formed. He also noted that such a system could become an alternative to animal models in research and contribute to the development of new non-opioid painkillers that do not cause addiction.

Stanford has already filed a patent application for the technology, but has not yet made a decision on its commercialization.

The research was published in the scientific journal Nature.