scholarly journals Leptin in the hindbrain facilitates phosphorylation of STAT3 in the hypothalamus

2015 ◽  
Vol 308 (5) ◽  
pp. E351-E361 ◽  
Author(s):  
Bhavna N. Desai ◽  
Ruth B. S. Harris
Keyword(s):  
Fourth Ventricle ◽  
Low Dose ◽  
Arcuate Nucleus ◽  
Third Ventricle ◽  
Ventromedial Hypothalamus ◽  
Sprague Dawley ◽  
Brain Nuclei ◽  
Dorsomedial Hypothalamus ◽  
The Third ◽  
Integrated Response

Leptin receptors (ObRs) in the forebrain and hindbrain have been independently recognized as important mediators of leptin responses. We recently used low-dose leptin infusions to show that chronic activation of both hypothalamic and hindbrain ObRs is required to reduce body fat. The objective of the present study was to identify the brain nuclei that are selectively activated in rats that received chronic infusion of leptin in both the forebrain and hindbrain. Either saline or leptin was infused into third and fourth ventricles (0.1 μg/24 h in the third ventricle and 0.6 μg/24 h in the fourth ventricle) of male Sprague-Dawley rats for 6 days using Alzet pumps. Rats infused with leptin into both ventricles (LL rats) showed a significant increase in phosphorylated (p)STAT3 immunoreactivity in the arcuate nucleus, ventromedial hypothalamus, dorsomedial hypothalamus, and posterior hypothalamus compared with other groups. No differences in pSTAT3 immunoreactivity were observed in midbrain or hindbrain nuclei despite a sixfold higher infusion of leptin into the fourth ventricle than the third ventricle. ΔFosB immunoreactivity, a marker of chronic neuronal activation, showed that multiple brain nuclei were chronically activated due to the process of infusion, but only the arcuate nucleus, ventromedial hypothalamus, dorsomedial hypothalamus, and ventral tuberomamillary nucleus showed a significant increase in LL rats compared with other groups. These data demonstrate that low-dose leptin in the hindbrain increases pSTAT3 in areas of the hypothalamus known to respond to leptin, supporting the hypothesis that leptin-induced weight loss requires an integrated response from both the hindbrain and forebrain.

scholarly journals Integrated Effects of Leptin in the Forebrain and Hindbrain of Male Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (8) ◽  
pp. 2663-2675 ◽  
Author(s):  
Bhavna N. Desai ◽  
Ruth B. S. Harris
Keyword(s):  
Weight Loss ◽  
Food Intake ◽  
Body Fat ◽  
Fourth Ventricle ◽  
Third Ventricle ◽  
Male Rats ◽  
Low Doses ◽  
Sprague Dawley ◽  
The Third ◽  
Stat3 Phosphorylation

Abstract Leptin receptors (ObRs) in the forebrain and hindbrain have been independently recognized as important mediators of leptin responses. It is unclear how leptin activity in these areas is integrated. We tested whether both forebrain and hindbrain ObRs have to be activated simultaneously to change energy balance and to maintain metabolic homeostasis. Previous studies used acute leptin injections in either the third ventricle (1–5 μg) or the fourth ventricle (3–10 μg); here we used 12-day infusions of low doses of leptin in one or both ventricles (0.1 μg/24 h in third, 0.6 μg/24 h in fourth). Male Sprague Dawley rats were fitted with third and fourth ventricle cannulas, and saline or leptin was infused from Alzet pumps for 6 or 12 days. Rats that received leptin into only the third or the fourth ventricle were not different from controls that received saline in both ventricles. By contrast, rats with low-dose leptin infusions into both the third and fourth ventricle showed a dramatic 60% reduction in food intake that was reversed on day 6, a 20% weight loss that stabilized on day 6, and a 50% decrease in body fat at day 12 despite the correction of food intake. They displayed normal activity and maintained energy expenditure despite weight loss, indicating inappropriately high thermogenesis that coincided with increased signal transducer and activator of transcription 3 (STAT3) phosphorylation in the brainstem. Altogether, these findings show that with low doses of leptin, chronic activation of both hypothalamic and brainstem ObRs is required to reduce body fat.

scholarly journals Low-dose leptin infusion in the fourth ventricle of rats enhances the response to third-ventricle leptin injection

2017 ◽  
Vol 313 (2) ◽  
pp. E134-E147 ◽  
Author(s):  
Ruth B. S. Harris
Keyword(s):  
Weight Loss ◽  
Food Intake ◽  
Fourth Ventricle ◽  
Low Dose ◽  
Respiratory Exchange Ratio ◽  
Third Ventricle ◽  
Separate Experiment ◽  
Rapid Weight Loss ◽  
Leptin Receptors ◽  
The Third

We previously reported that low-dose leptin infusions into the third or fourth ventricle that do not affect energy balance when given independently cause rapid weight loss when given simultaneously. Therefore, we tested whether hindbrain leptin enhances the response to forebrain leptin or whether forebrain leptin enhances the response to hindbrain leptin. Rats received fourth-ventricle infusions of saline or 0.01, 0.1, 0.3, or 0.6 μg leptin/day for 13 days. On days 9 and 13, 0.1 μg leptin was injected into the third ventricle. The injection inhibited food intake for 36 h in saline-infused rats but for 60 h in those infused with 0.6 μg leptin/day. Leptin injection increased intrascapular brown fat temperature in leptin-infused, but not saline-infused, rats. In a separate experiment, rats received third-ventricle infusions of saline or 0.005, 0.01, 0.05, or 0.1 μg leptin/day and fourth-ventricle injections of 1.0 μg leptin on days 9 and 13. Leptin injection inhibited food intake, respiratory exchange ratio, and 14-h food intake in rats infused with saline or the two lowest doses of leptin. There was no effect with higher-dose leptin infusions because food intake, body fat, and lean mass were already inhibited. These data suggest that activation of leptin receptors in the hindbrain enhances the response to third-ventricle leptin, whereas activation of forebrain leptin receptors does not enhance the response to fourth-ventricle leptin, consistent with our previous finding that weight loss in rats treated with fourth-ventricle leptin is associated with indirect activation of hypothalamic STAT3.

scholarly journals Blockade of the cerebral aqueduct in rats provides evidence of antagonistic leptin responses in the forebrain and hindbrain

2014 ◽  
Vol 306 (4) ◽  
pp. E414-E423 ◽  
Author(s):  
Michael I. Vaill ◽  
Bhavna N. Desai ◽  
Ruth B. S. Harris
Keyword(s):  
Weight Loss ◽  
Food Intake ◽  
Body Fat ◽  
Fourth Ventricle ◽  
Third Ventricle ◽  
Cerebral Aqueduct ◽  
Sprague Dawley ◽  
Leptin Receptors ◽  
The Third ◽  
Inhibit Food Intake

Previously, we reported that low-dose leptin infusions into the fourth ventricle produced a small but significant increase in body fat. These data contrast with reports that injections of higher doses of leptin into the fourth ventricle inhibit food intake and weight gain. In this study, we tested whether exogenous leptin in the fourth ventricle opposed or contributed to weight loss caused by third ventricle leptin infusion by blocking diffusion of CSF from the third to the fourth ventricle. Male Sprague-Dawley rats received third ventricle infusions of PBS or 0.3 μg leptin/24 h from miniosmotic pumps. After 4 days, rats received a 3-μl cerebral aqueduct injection of saline or of thermogelling nanoparticles (hydrogel) that solidified at body temperature. Third ventricle leptin infusion inhibited food intake and caused weight loss. Blocking the aqueduct exaggerated the effect of leptin on food intake and weight loss but had no effect on the weight of PBS-infused rats. Leptin reduced both body fat and lean body mass but did not change energy expenditure. Blocking the aqueduct decreased expenditure of rats infused with PBS or leptin. Infusion of leptin into the third ventricle increased phosphorylated STAT3 in the VMHDM of the hypothalamus and the medial NTS in the hindbrain. Blocking the aqueduct did not change hypothalamic p-STAT3 but decreased p-STAT3 in the medial NTS. These results support previous observations that low-level activation of hindbrain leptin receptors has the potential to blunt the catabolic effects of leptin in the third ventricle.

Neuroendoscopic Aspiration of Blood Clots in the Cerebral Aqueduct and Third Ventricle During Posterior Fossa Surgery in the Prone Position

2018 ◽  
Vol 17 (2) ◽  
pp. 143-148 ◽  
Author(s):  
Alberto Feletti ◽  
Riccardo Stanzani ◽  
Matteo Alicandri-Ciufelli ◽  
Giuliano Giliberto ◽  
Matteo Martinoni ◽  
...  
Keyword(s):  
Prone Position ◽  
Posterior Fossa ◽  
Fourth Ventricle ◽  
Blood Clot ◽  
Third Ventricle ◽  
Cerebral Aqueduct ◽  
Posterior Fossa Surgery ◽  
The Third ◽  
Blood Clots ◽  
Surgical Field

AbstractBACKGROUNDDuring surgery in the posterior fossa in the prone position, blood can sometimes fill the surgical field, due both to the less efficient venous drainage compared to the sitting position and the horizontally positioned surgical field itself. In some cases, blood clots can wedge into the cerebral aqueduct and the third ventricle, and potentially cause acute hydrocephalus during the postoperative course.OBJECTIVETo illustrate a technique that can be used in these cases: the use of a flexible scope introduced through the opened roof of the fourth ventricle with a freehand technique allows the navigation of the fourth ventricle, the cerebral aqueduct, and the third ventricle in order to explore the cerebrospinal fluid pathways and eventually aspirate blood clots and surgical debris.METHODSWe report on one patient affected by an ependymoma of the fourth ventricle, for whom we used a flexible neuroendoscope to explore and clear blood clots from the cerebral aqueduct and the third ventricle after the resection of the tumor in the prone position. Blood is aspirated with a syringe using the working channel of the scope as a sucker.RESULTSA large blood clot that was lying on the roof of the third ventricle was aspirated, setting the ventricle completely free. Other clots were aspirated from the right foramen of Monro and from the optic recess.CONCLUSIONWe describe this novel technique, which represents a safe and efficient way to clear the surgical field at the end of posterior fossa surgery in the prone position. The unusual endoscopic visual perspective and instrument maneuvers are easily handled with proper neuroendoscopic training.

scholarly journals Arcuate nucleus injection of an anti-insulin affibody prevents the sympathetic response to insulin

2013 ◽  
Vol 304 (11) ◽  
pp. H1538-H1546 ◽  
Author(s):  
Brittany S. Luckett ◽  
Jennifer L. Frielle ◽  
Lawrence Wolfgang ◽  
Sean D. Stocker
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Arcuate Nucleus ◽  
Insulin Receptors ◽  
Ventromedial Hypothalamus ◽  
Intracerebroventricular Injection ◽  
Sprague Dawley ◽  
Nerve Activity ◽  
Sympathetic Response ◽  
Sprague Dawley Rats

Accumulating evidence suggests that insulin acts within the hypothalamus to alter sympathetic nerve activity (SNA) and baroreflex function. Although insulin receptors are widely expressed across the hypothalamus, recent evidence suggests that neurons of the arcuate nucleus (ARC) play an important role in the sympathoexcitatory response to insulin. The purpose of the present study was to determine whether circulating insulin acts directly in the ARC to elevate SNA. In anesthetized male Sprague-Dawley rats (275–425 g), the action of insulin was neutralized by microinjection of an anti-insulin affibody (1 ng/40 nl). To verify the efficacy of the affibody, ARC pretreatment with injection of the anti-insulin affibody completely prevented the increase in lumbar SNA produced by ARC injection of insulin. Next, ARC pretreatment with the anti-insulin affibody attenuated the lumbar sympathoexcitatory response to intracerebroventricular injection of insulin. Third, a hyperinsulinemic-euglycemic clamp increased lumbar, but not renal, SNA in animals that received ARC injection of a control affibody. However, this sympathoexcitatory response was absent in animals pretreated with the anti-insulin affibody in the ARC. Injection of the anti-insulin affibody in the adjacent ventromedial hypothalamus did not alter the sympathoexcitatory response to insulin. The ability of the anti-insulin affibody to prevent the sympathetic effects of insulin cannot be attributed to a general inactivation or nonspecific effect on ARC neurons as the affibody did not alter the sympathoexcitatory response to ARC disinhibition by gabazine. Collectively, these findings suggest that circulating insulin acts within the ARC to increase SNA.

Critical surgical anatomy of the ventricular system

2010 ◽  
pp. 674-680
Author(s):  
George Samandouras
Keyword(s):  
Fourth Ventricle ◽  
Third Ventricle ◽  
Surgical Anatomy ◽  
Ventricular System ◽  
The Third ◽  
Lateral Ventricles ◽  
System P

Chapter 12.1 covers critical surgical anatomy of the ventricular system, including brief surgical embryology, brief clinical histology, the lateral ventricles, the third ventricle, the fourth ventricle, and major cisterns.

scholarly journals III. Contributions to the anatomy of the central nervous system in vertebrated animals. Part I.—Ichthyopsida. Section I.—Pisces. Subsection III.—Dipnoi. On the brain of the Ceratodus forsteri

1888 ◽  
Vol 43 (258-265) ◽  
pp. 420-423
Keyword(s):  
Fourth Ventricle ◽  
Third Ventricle ◽  
Pia Mater ◽  
The Third ◽  
Lateral Ventricles ◽  
Large Size ◽  
General Arrangement ◽  
Tela Choroidea ◽  
The Central Nervous System ◽  
The Brain

The brain of Ceratodus has the following general arrangement:—The membrane which represents the pia mater is of great thickness and toughness; there are two regions where a tela choroidea is developed: one where it covers in the fourth ventricle, and the other where it penetrates through the third ventricle and separates the lateral ventricles from each other. The ventricles are all of large size, and the walls of the lateral ventricles are not completed by nervous tissue. The thalamence-phalon and the mesencephalon are narrow, and the medulla oblongata is wide.

Organization of the Vascular Supply to the Brain of the Toad Bufo-Marinus

1990 ◽  
Vol 38 (4) ◽  
pp. 375
Author(s):  
GK Snyder ◽  
B Gannon ◽  
RV Baudinette
Keyword(s):  
Fourth Ventricle ◽  
Third Ventricle ◽  
Vascular Supply ◽  
Bufo Marinus ◽  
Cane Toad ◽  
The Third ◽  
Toad Bufo ◽  
The Brain ◽  
Caudal Rami ◽  
Vascular Corrosion Casts

The vasculature of the brain of the cane toad, Bufo marinus, was studied by means of scanning electron microscopy of vascular corrosion casts. The sole arterial supply to the brain is from branches of the internal carotids. The forebrain is supplied by several branches from the rostra1 ramus of the carotids; the caudal ramus gives rise to a single branch which supplies the mesencephalon and cerebellum. The caudal rami fuse to form a single basilar artery which supplies the medulla. The vascular supply to the choroid plexus of the third ventricle is arterial; the vascular supply to the choroid of the fourth ventricle is entirely venous. Microvascular geometry in the toad brain is specific to the region of the brain examined, ranging from simple long capillaries with few anastomotic connections to much shorter, highly convoluted capillaries with many anastomotic connections.

Sign in / Sign up

Export Citation Format

Share Document