Carotid sinus receptors participate in glucose homeostasis

This paper describes (a) the influence of glucose on carotid chemoreceptor activity, and (b) the participation of carotid receptors in glucose homeostasis. After eliminating the carotid body baroreceptors in anesthetized cats, the injection of glucose to the vascularly isolated carotid sinus region reduced by 20% the electrical activity of carotid body chemoreceptors and increased their threshold to hypoxia. Mannitol in the same concentration did not change the chemoreceptor activity. A decrease in baroreceptor activity elicited by carotid occlusion, or carotid chemoreceptor stimulation with 50 micrograms/kg cyanide (NaCN), produced an immediate increase in the output of hepatic glucose, raising the hepatic venous-arterial glucose difference above basal levels. Bilateral adrenalectomy eliminated these reflex responses. Cyanide injected in the same conditions caused a sharp increase in glucose retention by the brain. In control experiments, after sectioning the carotid nerve, NaCN injections were ineffective. However, electrical stimulation of the central stump of carotid nerve elicited reflex effects similar to those obtained with NaCN stimulation.