Pregnancy impairs baroreflex gain, but the mechanism is incompletely understood. To test the hypothesis that reductions in brain insulin contribute, we determined whether pregnant rats exhibit lower cerebrospinal fluid (CSF) insulin concentrations and whether intracerebroventricular infusion of insulin normalizes gain of baroreflex control of heart rate in conscious pregnant rats. CSF insulin w...

The role of reduced leptin signaling in the regulation of cardiovascular responses to negative energy balance is not known. We tested the hypothesis that central infusion of leptin would attenuate the cardiovascular and metabolic responses to fasting. Male Sprague-Dawley rats, instrumented with telemetry devices and intracerebroventricular cannulas, were housed in metabolic chambers for continu...

Ghrelin is an orexigenic peptide originally isolated from the stomach. Intravenous administration of ghrelin has been shown to elicit a decrease in arterial pressure without a significant change in heart rate (HR), suggesting that ghrelin may act on the central nervous system to modulate sympathetic activity. The aim of the present study was to determine the central effects of ghrelin on cardio...

OBJECTIVE Insulin inhibits endogenous glucose production (EGP) and stimulates glucose uptake in peripheral tissues. Hypothalamic insulin signaling is required for the inhibitory effects of insulin on EGP. We examined the contribution of central insulin signaling on circulating insulin-stimulated tissue-specific glucose uptake. RESEARCH DESIGN AND METHODS Tolbutamide, an inhibitor of ATP-sensi...

Leptin is an adipocyte-derived hormone that plays an important role in the regulation of energy homeostasis through its action in the central nervous system. Leptin decreases body weight by promoting satiety and increasing thermogenesis via increasing sympathetic nerve activity (SNA) to brown adipose tissue. Leptin also increases renal SNA and arterial pressure. The arcuate nucleus is considere...

There is evidence of crucial central nervous system involvement in the pathogenesis of mineralocorticoid-excess salt hypertension, as well as data indicating that corticosterone is the predominant ligand for the type I adrenocorticoid receptor in the brain. Miniosmotic pumps were used to deliver artificial cerebrospinal fluid (CSF), aldosterone (10 ng/h), corticosterone (10 or 20 ng/h), aldoste...

Nicotinic receptors in the brain modulate the release of many transmitters that are known to regulate voiding. This prompted us to examine the central nervous system effects of a neuronal nicotinic agonist, (+/-)-epibatidine, on voiding function in awake and anesthetized rats. Intracerebroventricular injection of (+/-)-epibatidine (0.1 microg) significantly increased intercontraction interval (...

To examine the role of the ventral anteroventral third ventricle (vAV3V) in the hypertension induced by chronic subcutaneous ouabain and intracerebroventricular hypertonic saline, neurons in this area were destroyed by microinjection of an excitotoxin, ibotenic acid. Sham-operated or lesioned Wistar rats were administered ouabain (50 μg/day) or placebo for 3 wk from subcutaneously implanted con...