Specialists from Tulane University, working in tandem with scientists from eight other research centers, have discovered a previously unnoticed mechanism of communication between nerve cells. The results of this study were published in the journal Science. The researchers demonstrated that neurons are capable of releasing the enzyme VLK (vertebrate-like kinase) into the extracellular space. This enzyme can modify protein structures on the surface of neighboring cells, thereby potentiating the interaction between receptor complexes involved in transmitting pain signals. Thus, VLK exerts a regulatory effect on the process of information exchange between cells. When VLK was removed from nociceptive sensory neurons in mice, the animals exhibited an absence of the typical postoperative pain response while maintaining normal behavioral patterns and adequate perception of their surroundings. Conversely, the introduction of additional amounts of VLK led to a marked enhancement of the pain response. According to the authors of the work, this model of interaction could serve as a basis for developing safer therapeutic approaches to managing pain syndrome. Targeted intervention on extracellularly functioning enzymes potentially minimizes the likelihood of undesirable side effects since the therapeutic intervention does not affect the intracellular receptor structures of the neurons. The Process of Pain Signal Generation A noxious stimulus initiates the activation of nociceptors. These highly sensitive sensory elements are located in the skin, internal organs, and mucous membranes. After stimulation, the nociceptor generates an action potential. Its generation is due to the opening of ion channels, which leads to the flow of electrical charges into the cell. This impulse travels along the nerve fiber to the spinal cord. There, neurons secrete mediators that facilitate the enhancement of signal transmission to the next level of the neural circuit. From the spinal cord, the afferent signal projects to the thalamus. This key structure is responsible for relaying information to the cerebral cortex. In the cortex, the final interpretation of the intensity and localization of the pain sensation occurs. The insular cortex and limbic structures (amygdala) are responsible for the emotional coloring, helping the brain assess the significance of the incoming signal.
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