scholarly journals Anatomical dissociation of melanocortin receptor agonist effects on taste- and gut-sensitive feeding processes

2011 ◽  
Vol 301 (4) ◽  
pp. R1044-R1056 ◽  
Author(s):  
John-Paul Baird ◽  
Mariana Palacios ◽  
Michael LaRiviere ◽  
Lindsay A. Grigg ◽  
Christopher Lim ◽  
...  
Keyword(s):  
Feedback Inhibition ◽  
Ingestion Rate ◽  
Third Ventricle ◽  
Brain Structures ◽  
Lick Rate ◽  
Melanocortin Receptor ◽  
Sucrose Solutions ◽  
Quinine Hydrochloride ◽  
Taste Evaluation ◽  
Reduced Rate

Injections of the melanocortin 3/4 receptor (MCR) agonist melanotan II (MTII) to a variety of brain structures produces anorexia, suggesting distributed brain MCR control of food intake. We performed a detailed analysis of feeding behavior (licking microstructure analysis) after a range of MTII doses (0.005 nM to 1 nM) was targeted to the forebrain (third ventricle, 3V) or hindbrain (fourth ventricle, 4V) regions. MTII (0.1 nM and 1 nM) delivered to the 3V or 4V significantly reduced 0.8 M sucrose intake. The anorexia was mediated by reductions in the number of licking bursts in the meal, intrameal ingestion rate, and meal duration; these measures have been associated with postingestive feedback inhibition of feeding. Anorexia after 3V but not 4V MTII injection was also associated with a reduced rate of licking in the first minute (initial lick rate) and reduced mean duration of licking bursts; these measures have been associated with taste evaluation. MTII effects on taste evaluation were further explored: In experiment 2, 3V MTII (1 nM) significantly reduced intake of noncaloric 4 mM saccharin and 0.1 M and 1 M sucrose solutions, but not water. The anorexia was again associated with reduced number of licking bursts, ingestion rate, meal duration, initial lick rate, and mean burst duration. In experiments 3 and 4, brief access (20 s) licking responses for sweet sucrose (0.015 M to 0.25 M) and bitter quinine hydrochloride (0.01 mM to 1 mM) solutions were evaluated. Licking responses for sucrose were suppressed, whereas those for quinine solutions were increased after 3V MTII, but not after 4V MTII injections (0.1 nM and 1 nM). The results suggest that multiple brain MCR sites influence sensitivity to visceral feedback, whereas forebrain MCR stimulation is necessary to influence taste responsiveness, possibly through attenuation of the perceived intensity of taste stimuli.

Effects of melanin-concentrating hormone on licking microstructure and brief-access taste responses

2006 ◽  
Vol 291 (5) ◽  
pp. R1265-R1274 ◽  
Author(s):  
John-Paul Baird ◽  
Catalina Rios ◽  
Nora Elizabeth Gray ◽  
Caroline Elizabeth Walsh ◽  
Shannon Glenora Fischer ◽  
...  
Keyword(s):  
Third Ventricle ◽  
Taste Stimulus ◽  
Water Solutions ◽  
The Third ◽  
Sucrose Solutions ◽  
Quinine Hydrochloride ◽  
Inhibitory Feedback ◽  
Melanin Concentrating Hormone ◽  
Taste Evaluation ◽  
The Mean

The effects of intracerebroventricular application of melanin-concentrating hormone (MCH) on licking for sucrose, quinine hydrochloride (QHCl), and water solutions were evaluated in two experiments. In experiment 1, rats received 90-min access to sucrose and water solutions after MCH or vehicle microinjection to the third ventricle (3V). MCH increased intake largely through increases in the rate of licking early in the meal and in the mean duration of lick bursts, suggesting an effect on gustatory evaluation. Therefore, in experiment 2, brief access tests were used with a series of sucrose and QHCl concentrations to behaviorally isolate the effects of intracerebroventricular MCH on gustatory evaluation. MCH uniformly increased licking for all sucrose solutions, water, and weak concentrations of QHCl; however, it had no effect on licking for the strongest concentrations of QHCl, which were generally avoided under control conditions. Thus MCH did not produce nonspecific increases in oromotor activity, nor did it change the perceived intensity of the tastants. We conclude that MCH enhanced the gain of responses to normally accepted stimuli at a phase of processing after initial gustatory detection and after the decision to accept or reject the taste stimulus. A comparison of 3V NPY and MCH effects on licking microstructure indicated that these two peptides increased intake via dichotomous behavioral processes; although NPY suppressed measures associated with inhibitory feedback from the gut, MCH appeared instead to enhance measures associated with hedonic taste evaluation.

scholarly journals Orexin-A Hyperphagia: Hindbrain Participation in Consummatory Feeding Responses

Endocrinology ◽  
2008 ◽  
Vol 150 (3) ◽  
pp. 1202-1216 ◽  
Author(s):  
John-Paul Baird ◽  
Angela Choe ◽  
Jasmine L. Loveland ◽  
Janine Beck ◽  
Carrie E. Mahoney ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Feedback Inhibition ◽  
Area Postrema ◽  
Burst Size ◽  
Ingestion Rate ◽  
Third Ventricle ◽  
Meal Size ◽  
Meal Frequency ◽  
Orexin A ◽  
Artificial Cerebrospinal Fluid

Orexin-A (ORXA) is an orexigenic neuropeptide produced by the lateral hypothalamus that increases food intake when injected into the brain ventricles or forebrain nuclei. We used a licking microstructure analysis to evaluate hindbrain and forebrain ORXA effects in intact and hindbrain-lesioned rats, to identify the motivational and anatomical bases of ORXA hyperphagia. Intact rats with cannulas in the fourth brain ventricle (4V) received vehicle (artificial cerebrospinal fluid) or ORXA (0.1, 0.4, 1, or 10 nm) injections before 90 min access to 0.1 m sucrose. Meal size and frequency were increased in a double-dissociated manner by the 1 and 10 nm doses, respectively. In experiment 2, 4V 1 nm ORXA was applied to rats offered solutions varied in caloric and gustatory intensity (water and 0.1 and 1 m sucrose). ORXA increased meal frequency for all tastants. ORXA increased meal size only for 0.1 m sucrose, by prolonging the meal without affecting early ingestion rate or lick burst size, suggesting that 4V ORXA influenced inhibitory postingestive feedback rather than taste evaluation. In experiment 3, rats with cannulas in the third ventricle (3V) received dorsal medullary lesions centered on the area postrema (APX group) or sham procedures, and licking for water and 0.1 and 1 m sucrose was evaluated after 1 nm 3V ORXA/artificial cerebrospinal fluid injections. The 3V ORXA increased 0.1 m sucrose meal size and meal frequency for all tastants in the sham group, as observed after 4V ORXA in experiment 2. In the APX group, 3V ORXA injections influenced meal frequency, but they no longer increased meal size. However, the APX rats increased meal size for 0.1 m sucrose after food and water deprivation and after 3V angiotensin II injection. They also showed meal size suppression after 3V injection of the melanocortin-3/4 receptor agonist melanotan II (1 nm). These findings suggest that the area postrema and subjacent nucleus of the solitary tract are necessary for increases in consummatory (meal size) but not appetitive (meal frequency) responses to 3V ORXA. The meal size increases may be due to reduced postingestive feedback inhibition induced by ORXA delivered to either the hindbrain or forebrain ventricles. Orexin-A increases meal size via gut feedback disinhibition, not enhanced gustatory evaluation. Medullary lesions abolish meal size but not frequency increases, indicating dissociable sites for orexin-A feeding actions.

scholarly journals Effects of hindbrain melanin-concentrating hormone and neuropeptide Y administration on licking for water, saccharin, and sucrose solutions

2008 ◽  
Vol 294 (2) ◽  
pp. R329-R343 ◽  
Author(s):  
John-Paul Baird ◽  
Catalina Rios ◽  
Jasmine L. Loveland ◽  
Janine Beck ◽  
Alice Tran ◽  
...  
Keyword(s):  
Neuropeptide Y ◽  
Ingestion Rate ◽  
Third Ventricle ◽  
Meal Frequency ◽  
Testing Conditions ◽  
The Third ◽  
Sucrose Solutions ◽  
Melanin Concentrating Hormone ◽  
The Brain ◽  
Early Phases

Melanin-concentrating hormone (MCH) and neuropeptide Y (NPY) are orexigenic peptides found in hypothalamic neurons that project throughout the forebrain and hindbrain. The effects of fourth ventricle (4V) infusions of NPY (5 μg) and MCH (5 μg) on licking for water, 4 mM saccharin, and sucrose (0.1 and 1.0 M) solutions were compared to identify the contributions of each peptide to hindbrain-stimulated feeding. NPY increased mean meal size only for the sucrose solutions, suggesting that caloric feedback or taste quality is pertinent to the orexigenic effect; MCH infusions under identical testing conditions failed to produce increases for any tastant. A second experiment also observed no intake or licking effects after MCH doses up to 15 μg, supporting the conclusion that MCH-induced orexigenic responses require forebrain stimulation. A third experiment compared the 4V NPY results with those obtained after NPY infusions (5 μg) into the third ventricle (3V). In contrast to the effects observed after the 3V NPY injections and previously reported forebrain intracerebroventricular (ICV) NPY infusion studies, 4V NPY failed to increase meal frequency for any taste solution or ingestion rate in the early phases of the sucrose meals. Overall, 4V NPY responses were limited to intrameal behavioral processes, whereas forebrain ICV NPY stimulation elicited both consummatory and appetitive responses. The dissociation between MCH and NPY effects observed for 4V injections is consistent with reports that forebrain ICV injections of MCH and NPY produced nearly dichotomous effects on the pattern of licking microstructure, and, collectively, the results indicate that the two peptides have separate sites of feeding action in the brain.

Osmosensitivity of rat third ventricle and interactions with angiotensin

1979 ◽  
Vol 236 (1) ◽  
pp. R75-R82 ◽  
Author(s):  
J. Buggy ◽  
W. E. Hoffman ◽  
M. I. Phillips ◽  
A. E. Fisher ◽  
A. K. Johnson
Keyword(s):  
Third Ventricle ◽  
Neural Substrates ◽  
Short Latency ◽  
Neural Mechanisms ◽  
Nacl Solution ◽  
Pressor Responses ◽  
Sucrose Solutions ◽  
Osmotic Stimulation ◽  
Behavioral Dissociation ◽  
Drinking Fluid

Injections of hyperosmotic solutions (1- to 5-microliter injections of NaCl or sucrose solutions ranging in osmolarity from 0.34 to 0.90 osmol/l) into the anteroventral third ventricle (AV3V) of rats resulted in short latency drinking antidiuretic, and pressor responses. AV3V injections or infusions of combined angiotensin-hyperosmotic NaCl solution did not result in drinking greater than the sum of drinking to angiotensin and hyperosmotic NaCl separately administered. Differences in water versus saline drinking fluid preferences provided a behavioral dissociation of angiotensin and hyperosmotic sensitive neural mechanisms. Comparison of AV3V and lateral preoptic injection sites provided an additional separation since angiotensin was equally effective at both sites whereas osmotic stimulation was more effective at the AV3V site. AV3V lesions have previously been reported to abolish drinking, antidiuretic, and pressor responses to angiotensin and hyperosmotic stimulation. The data reported here provide additional evidence that angiotensin and hyperosmotic stimuli may both act on tissue surrounding AV3V but suggest that the neural substrates for these stimuli are not identical.

scholarly journals Central Infusion of Agouti-Related Peptide Suppresses Pulsatile Luteinizing Hormone Release in the Ovariectomized Rhesus Monkey

Endocrinology ◽  
2005 ◽  
Vol 146 (2) ◽  
pp. 784-789 ◽  
Author(s):  
Nicolas R. Vulliémoz ◽  
Ennian Xiao ◽  
Linna Xia-Zhang ◽  
Sharon L. Wardlaw ◽  
Michel Ferin
Keyword(s):  
Pulse Generator ◽  
Third Ventricle ◽  
Reproductive Function ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Melanocortin Receptor ◽  
Central Administration ◽  
Related Peptide ◽  
Orexigenic Peptide ◽  
Lh Release

Abstract Agouti-related peptide (AGRP), an endogenous melanocortin receptor antagonist, is a powerful orexigenic peptide when infused centrally. AGRP and neuropeptide Y (NPY), another orexigenic peptide, are colocated within the same neurons in the arcuate nucleus. Both NPY and AGRP mRNA expression increases during food restriction, a condition that is known to suppress the GnRH pulse generator and reproductive function. Although NPY has been shown previously to suppress LH secretion in the ovariectomized monkey, data on AGRP are lacking. In this study, we examined the effect of AGRP infusion into the third ventricle on pulsatile LH release in five adult monkeys. The 8-h protocol included a 3-h intraventricular saline infusion to establish baseline pulsatile LH release, followed by a 5-h infusion of AGRP (83–132) [5 μg/h (n = 1) or 10 μg/h (n = 4)]. In separate experiments, each animal received an 8-h saline treatment as a control. Blood samples were collected every 15 min for LH measurements. Cortisol levels were measured every 45 min. AGRP infusion significantly decreased LH pulse frequency (from a baseline of 0.74 ± 0.07 pulse/h to 0.36 ± 0.12 during AGRP infusion; P < 0.01) and mean LH concentrations (to 41.1 ± 7.5% of baseline by h 5 of AGRP infusion; P < 0.001). LH pulse amplitude was not modified by AGRP treatment. AGRP infusion also significantly increased cortisol release, as previously reported. The data demonstrate that central administration of AGRP inhibits pulsatile LH release in the monkey and suggest that AGRP, like NPY, may mediate the effect of a negative energy balance on the reproductive system by suppressing the GnRH pulse generator.

Tumors of the Lateral and Third Ventricle: Removal under Endoscope-assisted Keyhole Conditions

2005 ◽  
Vol 57 (suppl_4) ◽  
pp. ONS-302-ONS-311 ◽  
Author(s):  
Patra Charalampaki ◽  
Ronald Filippi ◽  
Stefan Welschehold ◽  
Jens Conrad ◽  
Axel Perneczky
Keyword(s):  
Minimally Invasive ◽  
Third Ventricle ◽  
Brain Structures ◽  
Skin Incision ◽  
Neurological Deficits ◽  
Invasive Technique ◽  
Magnetic Resonance Imaging Scan ◽  
Keyhole Concept ◽  
Surgical Corridor ◽  
Brain Retraction

Abstract OBJECTIVE: Intraventricular tumors usually are managed by approaches and microsurgical techniques that need retraction and dissection of important brain structures. Minimally invasive endoscopic procedures achieve a remarkable alternative to conventional microneurosurgical techniques. Endoscope-assisted microneurosurgery may be a minimally invasive technique with maximally effective treatment. Using the keyhole concept for planning the surgical strategy, the reduction of the brain retraction is achieved, which is one of the main benefits of this technique. METHODS: We treated 35 patients (16 female patients and 19 male patients) with tumors in the lateral (n = 8) and the third (n = 27) ventricle. Patient age at the date of surgery ranged from 5 to 73 years. The follow-up period ranged from 6 to 83 months. The tumors were operated on using transcortical, transcallosal, or suboccipital transtentorial or infratentorial supracerebellar approaches after precise planning of the skin incision, the trephination, and the trajectory to the center of the tumor, performed earlier with a magnetic resonance imaging scan. RESULTS: Total removal of the tumor was achieved in 28 patients (78.5%). In 2 patients (6.5%), recurrent tumor occurred. In 5 patients (15%), parts of the tumors remained because of infiltration of eloquent areas. Overall clinical improvement was achieved in 31 patients (87%). Three patients (10%) were unchanged and 1 patient (3%) deteriorated. CONCLUSION: Endoscope-assisted keyhole neurosurgery seems to be a safe method of removing tumors in all regions inside the ventricular system with a low risk of permanent neurological deficits. The exact surgical corridor planning on the basis of the keyhole strategy offers less traumatic exposure of even deep-seated endoventricular tumors.

scholarly journals The Epic of the Thalamus in Anatomical Language

2021 ◽  
Vol 15 ◽  
Author(s):  
Miguel Ángel García-Cabezas ◽  
Isabel Pérez-Santos ◽  
Carmen Cavada
Keyword(s):  
Middle Ages ◽  
Third Ventricle ◽  
Medical Knowledge ◽  
Hollow Structure ◽  
Brain Structures ◽  
Greek Language ◽  
Brain Ventricles ◽  
The North ◽  
Anatomical Terminology ◽  
History Of

Understanding the origin of Greek and Latin words used as metaphors to label brain structures gives a unique window into how scientific and medical knowledge was produced, preserved, and transmitted through generations. The history of the term thalamus exemplifies the complex historical process that led to the current anatomical terminology. From its first mention by Galen of Pergamon in the 2nd century A.D. to its definitive and current use by Thomas Willis in 1664, the thalamus had an epical journey through 1500 years across Europe, the Middle East, and the North of Africa. The thalamus was confusingly described by Galen, in the Greek language, as a chamber to the brain ventricles. The term thalamus was transferred from Greek to Syriac through the translations of Galen’s books done in Baghdad and also from Syriac to Arabic. Then, it was translated in Europe during the Middle Ages from the Arabic versions of Galen’s books to Latin. Later, during the Early Renaissance, it was translated again to Latin directly from the Greek versions of Galen’s books. Along this epical journey through languages, the term thalamus switched from referring to a hollow structure connected to brain ventricles to naming a solid structure at the rostral end of the brainstem. Finally, the thalamus was translated from Latin to modern languages, where it is used, until today, to name a nuclear complex of subcortical gray matter in the lateral walls of the third ventricle.

Dilute bird nectars: viscosity constrains food intake by licking in a sunbird

2010 ◽  
Vol 299 (4) ◽  
pp. R1068-R1074 ◽  
Author(s):  
Angela Köhler ◽  
Carolina D. C. Leseigneur ◽  
Luke Verburgt ◽  
Susan W. Nicolson
Keyword(s):  
Food Intake ◽  
Sucrose Concentration ◽  
Ingestion Rate ◽  
High Viscosity ◽  
Sugar Concentration ◽  
Sucrose Intake ◽  
Total Food Intake ◽  
Total Food ◽  
Sucrose Solutions ◽  
Viscous Solutions

Floral nectars of bird-pollinated plants are relatively dilute. One hypothesis proposed to explain this concerns the difficulty for birds of drinking nectar of high viscosity. We examined the effects of viscosity, separately from those of sugar concentration, on feeding by captive whitebellied sunbirds ( Cinnyris talatala ). Viscosities of artificial nectar (sucrose solutions ranging in concentration from 0.25 to 1.5 mol/l) were altered with Tylose, an inert polysaccharide. Food consumption was measured over 3 h, and lick frequency and duration were recorded using photodetection devices on feeding apertures too small for the bill but large enough for the extended tongue. Volumetric intake rates (ml/s) were inversely proportional to nectar viscosity, and were similar over the range of sucrose concentrations when viscosity was held constant. Sucrose intake rates (mg/s) remained the same on pure sucrose solutions, but they decreased with increasing viscosity at a constant sucrose concentration. Lick frequencies and tongue loads were reduced at high viscosities, and lick duration increased, which confirms that sunbirds take longer to ingest viscous solutions. Licking behavior was remarkably similar in birds feeding on different sucrose concentrations if viscosity was held constant. Nectar ingestion rate is determined by viscosity; however, total food intake is mainly modulated by sugar concentration. Similar effects of food viscosity have been observed in insects that suck nectar.

scholarly journals Brain morphology in antipsychotic-naïve schizophrenia: A study of multiple brain structures

2002 ◽  
Vol 181 (S43) ◽  
pp. s66-s72 ◽  
Author(s):  
W. Cahn ◽  
H. E. Hulshoff Pol ◽  
M. Bongers ◽  
H. G. Schnack ◽  
R. C. W. Mandl ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Third Ventricle ◽  
Chronic Schizophrenia ◽  
Brain Structures ◽  
Brain Regions ◽  
Brain Morphology ◽  
First Episode ◽  
Intracranial Volume ◽  
Brain Abnormalities ◽  
Ventricle Volume

BackgroundAlthough brain volume changes are found in schizophrenia, only a limited number of structural magnetic resonance imaging studies have exclusively examined antipsychotic-naïve patients.AimsTo comprehensively investigate multiple brain structures in a single sample of patients who were antipsychotic-naïve.MethodTwenty antipsychotic-naïve patients with first-episode schizophrenia and 20 healthy comparison subjects were included. Intracranial, total brain, frontal lobe, grey and white matter, cerebellar, hippocampal, parahippocampal, thalamic, caudate nucleus and lateral and third ventricular volumes were measured. Repeated-measures analyses of (co)variance were conducted with intracranial volume as covariate.ResultsThird ventricle volume enlargement was found in patients compared with the healthy subjects. No differences were found in other brain regions.ConclusionsThese findings suggest that some brain abnormalities are present in the early stages of schizophrenia. Moreover, it suggests that brain abnormalities reported in patients with chronic schizophrenia develop in a later stage of the disease and/or are medication induced.

scholarly journals Nutritional Omega-3 Deficiency Alters Glucocorticoid Receptor-Signaling Pathway and Neuronal Morphology in Regionally Distinct Brain Structures Associated with Emotional Deficits

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Thomas Larrieu ◽  
Muna L. Hilal ◽  
Véronique De Smedt-Peyrusse ◽  
Nathalie Sans ◽  
Sophie Layé
Keyword(s):  
Glucocorticoid Receptor ◽  
Signaling Pathway ◽  
Feedback Inhibition ◽  
Brain Structures ◽  
Neuronal Morphology ◽  
Omega 3 ◽  
Corticosterone Secretion ◽  
Emotional Behaviour ◽  
Emotional Deficits ◽  
Deficient Mice

Extensive evidence suggests that long term dietary n-3 polyunsaturated fatty acids (PUFAs) deficiency results in altered emotional behaviour. We have recently demonstrated that n-3 PUFAs deficiency induces emotional alterations through abnormal corticosterone secretion which leads to altered dendritic arborisation in the prefrontal cortex (PFC). Here we show that hypothalamic-pituitary-adrenal (HPA) axis feedback inhibition was not compromised in n-3 deficient mice. Rather, glucocorticoid receptor (GR) signaling pathway was inactivated in the PFC but not in the hippocampus of n-3 deficient mice. Consequently, only dendritic arborisation in PFC was affected by dietary n-3 PUFAs deficiency. In addition, occlusion experiment with GR blockade altered GR signaling in the PFC of control mice, with no further alterations in n-3 deficient mice. In conclusion, n-3 PUFAs deficiency compromised PFC, leading to dendritic atrophy, but did not change hippocampal GR function and dendritic arborisation. We argue that this GR sensitivity contributes to n-3 PUFAs deficiency-related emotional behaviour deficits.

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