Preoptic BRS3 neurons increase body temperature and heart rate via multiple pathways

Area of Science:

• Neuroscience
• Physiology
• Homeostasis

Background:

• The preoptic area (POA) is crucial for regulating body temperature (Tb).
• Previous studies identified POA neurons that decrease Tb upon activation.
• The specific neuronal populations responsible for increasing Tb remained largely unknown.

Purpose of the Study:

• To identify and characterize novel neuronal populations within the POA that regulate body temperature.
• To investigate the role of bombesin-like receptor 3 (BRS3)-expressing neurons in thermoregulation.
• To elucidate the neural pathways involved in BRS3-mediated temperature control.

Main Methods:

• Utilized mouse models to investigate neuronal function.
• Employed genetic and viral strategies to target and manipulate POA neurons expressing BRS3.
• Measured body temperature, heart rate, and blood pressure.
• Analyzed neuronal projections using immunohistochemistry.
• Performed RNA sequencing on POA^BRS3 neurons.

Main Results:

• Activation of POA neurons expressing BRS3 (POA^BRS3) increased Tb.
• Inhibition of POA^BRS3 neurons decreased Tb.
• Projections from POA^BRS3 neurons to the paraventricular nucleus and dorsomedial hypothalamus elevated Tb, heart rate, and blood pressure via the sympathetic nervous system.
• Long-term inactivation led to increased Tb variability, indicating impaired feedback control.
• RNA expression profiles suggested heterogeneity within the POA^BRS3 neuronal population.

Conclusions:

• POA^BRS3 neurons are identified as a critical population that increases body temperature and heart rate.
• These neurons play a significant role in cold defense mechanisms.
• POA^BRS3 neurons contribute to the fine-tuning of Tb feedback control, essential for mammalian homeothermy.