Autonomic Regulation of Inflammation in Conscious Animals

Abstract

Bioelectronic medicine is a novel field in modern medicine based on the specific neuronal stimulation to control organ function, cardiovascular, and immune homeostasis. However, most studies addressing neuromodulation of the immune system have been conducted on anesthetized animals, which can affect the nervous system and neuromodulation. Here, we review recent studies involving conscious experimental rodents (rats and mice) to better understand the functional organization of neural control of immune homeostasis. We highlight typical experimental models of cardiovascular regulation, such as electrical activation of the aortic depressor nerve or the carotid sinus nerve, bilateral carotid occlusion, the Bezold-Jarisch reflex, and intravenous administration of the bacterial endotoxin lipopolysaccharide. These models have been used to investigate the relationship between neuromodulation of the cardiovascular and immune systems in conscious rodents (rats and mice). These studies provide critical information about the neuromodulation of the immune system, particularly the role of the autonomic nervous system, i.e., the sympathetic and parasympathetic branches acting both centrally (hypothalamus, nucleus ambiguus, nucleus tractus solitarius, caudal ventrolateral medulla, and rostral ventrolateral medulla), and peripherally (particularly spleen and adrenal medulla). Overall, the studies in conscious experimental models have certainly highlighted to the reader how the methodological approaches used to investigate cardiovascular reflexes in conscious rodents (rats and mice) can also be valuable for investigating the neural mechanisms involved in inflammatory responses. The reviewed studies have clinical implications for future therapeutic approaches of bioelectronic modulation of the nervous system to control organ function and physiological homeostasis in conscious physiology.

Keywords: Baroreflex; Bezold-Jarisch reflex; Chemoreflex; Conscious rats; Inflammatory reflex.