Interleukin 6 (IL-6) Regulates GABAA Receptors in the Dorsomedial Hypothalamus Nucleus (DMH) through Activation of the JAK/STAT Pathway to Affect Heart Rate Variability in Stressed Rats

The dorsomedial hypothalamus nucleus (DMH) is an important component of the autonomic nervous system and plays a critical role in regulating the sympathetic outputs of the heart. Stress alters the neuronal activity of the DMH, affecting sympathetic outputs and triggering heart rate variability. However, the specific molecular mechanisms behind stress leading to abnormal DMH neuronal activity have still not been fully elucidated. Therefore, in the present study, we successfully constructed a stressed rat model and used it to investigate the potential molecular mechanisms by which IL-6 regulates GABAA receptors in the DMH through activation of the JAK/STAT pathway and thus affects heart rate variability in rats. By detecting the c-Fos expression of neurons in the DMH and electrocardiogram (ECG) changes in rats, we clarified the relationship between abnormal DMH neuronal activity and heart rate variability in stressed rats. Then, using ELISA, immunohistochemical staining, Western blotting, RT-qPCR, and RNAscope, we further explored the correlation between the IL-6/JAK/STAT signaling pathway and GABAA receptors. The data showed that an increase in IL-6 induced by stress inhibited GABAA receptors in DMH neurons by activating the JAK/STAT signaling pathway, while specific inhibition of the JAK/STAT signaling pathway using AG490 obviously reduced DMH neuronal activity and improved heart rate variability in rats. These findings suggest that IL-6 regulates the expression of GABAA receptors via the activation of the JAK/STAT pathway in the DMH, which may be an important cause of heart rate variability in stressed rats.

Automated summary

The dorsomedial hypothalamus nucleus (DMH) is responsible for regulating sympathetic outputs of the heart. Stress alters DMH neuronal activity and affects heart rate variability, but the molecular mechanisms behind this are not fully understood. In this study, a stressed rat model was used to investigate the role of IL-6 in regulating GABAA receptors in the DMH through the JAK/STAT pathway and its impact on heart rate variability. The findings suggest that IL-6 inhibits GABAA receptors in DMH neurons by activating the JAK/STAT pathway, leading to abnormal DMH neuronal activity and heart rate variability in stressed rats.