Central injection of leptin increases sympathetic nerve outflows to the stomach and spleen in anesthetized rats

Abstract

Background/Aim: Leptin, one of the hormones produced in white adipose tissue, is an efferent sympathetic stimulator. Actually, an injection of leptin into the brain has been shown to activate sympathetic nerve activities innervating the kidney, adrenal gland, adipose tissues, liver, and lumbar in rats. Materials and Methods: This study investigated the effects of an intracerebroventricular injection of leptin on the activities of sympathetic nerves innervating the stomach and spleen in anesthetized rats. Results: Leptin injection activated the neural activities of sympathetic traffic to both the stomach and spleen. In addition, to investigate the role of AMP-activated protein kinase (AMPK), the effects of 5-aminoimidazole-4-carboxamide 1-beta-D-ribofuranoside (AICAR), an AMPK activator, or compound C, an AMPK inhibitor, on leptin-induced sympathoexcitation, were assessed. Central pretreatment with AICAR or compound C eliminated not only leptin-induced gastric sympathoexcitation but also leptin-induced splenic sympathoexcitation. Conclusion: Leptin stimulates efferent sympathetic outflow to the stomach and spleen through the hypothalamic AMPK.