Thirty oxytocinergic neurons simultaneously relieve mind and body!

An international study, coordinated by Drs Valery Grinevich (DKFZ, ZI, CellNetworks, Heidelberg), Ron Stoop (Lausanne University) and Alexandre Charlet (CNRS INCI, Strasbourg), has identified a new analgesia-controlling center within the hypothalamus. The center contains about 30 neurons that coordinate the release of oxytocin into the bloodstream and in the central nervous system, all the way to the spinal cord. Their important results are detailed in an article published in Neuron.

Oxytocin is a peptide synthesized by the hypothalamus. As a hormone, its release into the blood controls several functions, the most widely known being the contraction of the uterus during birth and the release of maternal milk following birth. Its additional role as a neurotransmitter has been shown by several studies, highlighting oxytocin’s involvement in social communication, development of anxiety, stress response and, recently, pain.

The team of Drs. Valery Grinevich, Ron Stoop and Alexandre Charlet had identified a group of about thirty oxytocinergic neurons that act as taskmasters in order to coordinate the global analgesic effect of oxytocin. These neurons are solicited during episodes of acute pain or inflammatory sensitization. Under these conditions, they first activate a family of magnocellular neurons in the neighboring supraoptic nucleus, thus triggering the release of oxytocin into the bloodstream. This leads to a diffuse analgesic effect by reducing the sensory perception of peripheral neurons that relay nociceptive information. Via long-range axons, these neurons reach the deep layers of the spinal cord and secrete oxytocin precisely at the level where the intensity of the nociceptive message is encoded in the central nervous system. Thus, the release of oxytocin acts via a dual pathway: first, it reduces the perception of pain and second, it filters the nociceptive input into the central nervous system.

The results provide evidence for anatomical and functional heterogeneity within the central oxytocin system and offer a new direction for research of mechanisms of coordinated oxytocin regulation of autonomic functions and behavior. Furthermore, from now on, oxytocin can be seen not only as a potential drug for treatment of social deficits in patients with autisms or schizophrenia, but also as a promising therapeutic agent alleviating acute pain.

Published work of Valery Grinevich team was performed in line and under support of SFB 1158.