Abstract
Adiponectin plays important roles in the control of energy homeostasis and autonomic function through peripheral and central nervous system actions. The paraventricular nucleus (PVN) of the hypothalamus is a primary site of neuroendocrine (NE) and autonomic integration, and, thus, a potential target for adiponectin actions. Here, we investigate actions of adiponectin on parvocellular PVN neurons. Adiponectin influenced the majority (65%) of parvocellular PVN neurons, depolarizing 47%, whereas hyperpolarizing 18% of neurons tested. Post hoc identification (single-cell RT-PCR) after recordings revealed that adiponectin depolarizes NE-CRH neurons, whereas intracerebroventricular injections of adiponectin in vivo caused increased plasma ACTH concentrations. Adiponectin also depolarized the majority of TRH neurons, however, NE-TRH neurons were unaffected, in accordance with in vivo experiments showing that intracerebroventricular adiponectin was without effect on plasma TSH. In addition, bath administration of adiponectin also depolarized both preautonomic TRH and oxytocin neurons. These results show that adiponectin acts in the central nervous system to coordinate NE and autonomic function through actions on specific functional groups of PVN neurons.