Emergent Roles of RVLMC1 Neurons in Cardiovascular Homeostasis and Systemic Physiological Regulation

Abstract Purpose of the Review Adrenergic C1 neurons in the rostral ventrolateral medulla (RVLM C1 ) have long been recognized for their role in regulating sympathetic activity and arterial blood pressure (BP). However, novel approaches such as genetic targeting, optogenetics, fiber photometry, among others, allowed us to study the biology of these neurons in deeper detail and in non-anesthetized preparations, unraveling previously underappreciated or unrecognized functions. Here we will discuss recent studies that explored the function of RVLM C1 neurons for the sympathetic regulation of BP and also the emergent roles of these cells for other processes involved in systemic physiological regulation. Recent Findings Using selective methods of manipulation and recording of neuronal activity in conscious animals, it was demonstrated that RVLM C1 neurons play a critical role in BP stability across multiple behaviors, including sleep-wake state and postural changes. Besides cardiovascular control, recent evidence shows that these neurons play a critical role in different homeostatic functions such as thermoregulation, immune response, glycemia and in complex behaviors such as anxiety. Summary RVLM C1 neurons are a key hub that integrates interoceptive signals from peripheral systems to regulate BP and other basic physiological functions. Along with their role in cardiovascular regulation, these emergent roles of RVLM C1 neurons may also need to be considered when explaining the complex and multifactorial pathophysiology of cardiometabolic diseases associated with hypertension.