Making sense of the carotid body counter‐regulatory response to hypoglycaemia

Abstract

The homeostatic control of blood glucose is critical to life.Contemporary concerns relating to metabolic disorders are primarily focused on the deleterious consequences of abundant energy intake and the resultant long-term consequences of insulin resistance and hyperglycaemia. However, an acute reduction in blood glucose concentration presents an immediate and substantive stress to the brain, which is avidly countered by neurohumoral responses that serve to restore and protect normoglycaemia.The carotid bodies are recognised as polymodal sensors that taste the arterial blood perfusing the brain. Whereas there has been a longstanding interest in the pivotal role of the carotid bodies in oxygen sensing, in recent years it has become evident that carotid body chemoreceptors play a critical role in the reflex response to a range of stressors including the counter-regulatory response to hypoglycaemia. In this issue ofExperimental Physiology, Baby et al. (2023) report for the first time the acute effects of insulin-induced hypoglycaemia on carotid body chemoreceptor activity and cardiorespiratory responsiveness in vivo in a large animal model. In anaesthetised dogs, afferent neural traffic from both carotid bodies (carotid sinus nerve activity), respiratory flow, heart rate and arterial blood pressure were recorded. Insulin was administered by intracarotid infusion and carotid body and cardiorespiratory responses to intracarotid sodium cyanide (a carotid body stimulant) were determined during normoglycaemia and hypoglycaemia. Insulin-mediated hypoglycaemia increased carotid sinus nerve activity and ventilation, which partially offset the hypermetabolic This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.