Hypothalamic neuronal circuits regulating hunger-induced taste modification

Abstract The gustatory system plays a critical role in sensing appetitive and aversive taste stimuli for evaluating food quality. Although taste preference is known to change depending on internal states such as hunger, a mechanistic insight remains unclear. Here, we examine the neuronal mechanisms regulating hunger-induced taste modification. Starved mice exhibit an increased preference for sweetness and tolerance for aversive taste. This hunger-induced taste modification is recapitulated by selective activation of orexigenic Agouti-related peptide (AgRP)-expressing neurons in the hypothalamus projecting to the lateral hypothalamus, but not to other regions. Glutamatergic, but not GABAergic, neurons in the lateral hypothalamus function as downstream neurons of AgRP neurons. Importantly, these neurons play a key role in modulating preferences for both appetitive and aversive tastes by using distinct pathways projecting to the lateral septum or the lateral habenula, respectively. Our results suggest that these hypothalamic circuits would be important for optimizing feeding behavior under fasting.

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Pain, Anxiety- and Depression-Like Behaviors in Alcohol-Preferring and -NonPreferring Rats

Neurology and Neurobiology ◽

10.31487/j.nnb.2020.02.05 ◽

2020 ◽

pp. 1-8

Author(s):

Jiang-Hong Ye ◽

Emily Bian ◽

Jiang-Hong Ye ◽

Jing Li ◽

Michal Gajewski ◽

...

Keyword(s):

Alcohol Consumption ◽

Critical Role ◽

Alcohol Exposure ◽

Anxiety And Depression ◽

Mechanical Stimuli ◽

Lateral Habenula ◽

Pain Anxiety ◽

Calcium Calmodulin Dependent ◽

Neuronal Mechanisms ◽

Dependent Protein

Introduction: Psychiatric disorders such as anxiety, hyperalgesia, and depression have been associated with excessive alcohol drinking, but the neuronal mechanisms involved are only partially understood. Alcoholism more often occurs in individuals with a family history, indicating that genes may play a critical role. Chronic alcohol exposure alters calcium/calmodulin-dependent protein kinase II (CaMKII) signaling in the lateral habenula (LHb), and the LHb is implicated in mediating aversive behaviors, including those related to alcohol. We compared the CaMKII signaling in the LHb and the aberrant behaviors in the selectively bred alcohol-preferring (P) and alcohol-non-preferring (NP) lines of rats. Materials and Methods: The responses to mechanical (Von Frey) and thermal (Hargreaves) nociception tests, anxiety- (elevated plus maze, Marble burying) and depressive-like behaviors (forced swimming) were examined in the alcohol-naïve P and NP rats, as well as in P rats after 4-8 weeks of alcohol consumption; their LHb tissues were also collected for Western blot analysis of CaMKII expression. Results: Compared to NP rats, the P rats had a higher sensitivity to mechanical stimuli, and displayed depressive- and anxiety-like behaviors, as well as a higher level of CaMKII in the LHb. Alcohol consumption alleviated all these behaviors, except for anxiety, and decreased CaMKII levels in the LHb of P rats. Conclusions: The results show that selective breeding for different oral alcohol preference has produced differences in nociception, anxiety, and depression, as well as CaMKII expression in the LHb of P and NP rats. P rats may deal with pain and depression by self-medicating with alcohol.

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Lateral hypothalamus orexinergic inputs to lateral habenula modulate maladaptation after social defeat stress

Neurobiology of Stress ◽

10.1016/j.ynstr.2021.100298 ◽

2021 ◽

Vol 14 ◽

pp. 100298

Author(s):

Dan Wang ◽

Ao Li ◽

Keyi Dong ◽

Huihui Li ◽

Yongxin Guo ◽

...

Keyword(s):

Lateral Hypothalamus ◽

Social Defeat ◽

Social Defeat Stress ◽

Lateral Habenula

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Drosophila Central Taste Circuits in Health and Obesity

10.5772/intechopen.99643 ◽

2021 ◽

Author(s):

Shivam Kaushik ◽

Shivangi Rawat ◽

Pinky Kain

Keyword(s):

Internal State ◽

Taste Preference ◽

Taste Perception ◽

Model Organisms ◽

Gustatory System ◽

Neuronal Circuits ◽

Neural Basis ◽

Metabolic Conditions ◽

Feeding Choices ◽

Feeding Behaviours

When there is a perturbation in the balance between hunger and satiety, food intake gets mis-regulated leading to excessive or insufficient eating. In humans, abnormal nutrient consumption causes metabolic conditions like obesity, diabetes, and eating disorders affecting overall health. Despite this burden on society, we currently lack enough knowledge about the neuronal circuits that regulate appetite and taste perception. How specific taste neuronal circuits influence feeding behaviours is still an under explored area in neurobiology. The taste information present at the periphery must be processed by the central circuits for the final behavioural output. Identification and understanding of central neural circuitry regulating taste behaviour and its modulation by physiological changes with regard to internal state is required to understand the neural basis of taste preference. Simple invertebrate model organisms like Drosophila melanogaster can sense the same taste stimuli as mammals. Availability of powerful molecular and genetic tool kit and well characterized peripheral gustatory system with a vast array of behavioural, calcium imaging, molecular and electrophysiological approaches make Drosophila an attractive system to investigate and understand taste wiring and processing in the brain. By exploiting the gustatory system of the flies, this chapter will shed light on the current understanding of central neural taste structures that influence feeding choices. The compiled information would help us better understand how central taste neurons convey taste information to higher brain centers and guide feeding behaviours like acceptance or rejection of food to better combat disease state caused by abnormal consumption of food.

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0067 An Anatomic Substrate for GABAergic Processes to Suppress Active Sleep and Promote Wakefulness in the Nucleus Pontis Oralis

SLEEP ◽

10.1093/sleep/zsaa056.065 ◽

2020 ◽

Vol 43 (Supplement_1) ◽

pp. A27-A27

Author(s):

J Zhang ◽

S Sampogna ◽

M Xi ◽

S J Fung ◽

C Tobin ◽

...

Keyword(s):

Polyclonal Antibodies ◽

Critical Role ◽

Direct Interaction ◽

Gabaergic Inhibition ◽

Active Sleep ◽

Neuronal Somata ◽

Neuronal Mechanisms ◽

Adult Cats ◽

Fluorescence Immunohistochemistry ◽

Anatomical Evidence

Abstract Introduction Our previous electrophysiologic data have provided compelling evidence that GABAergic processes in the nucleus pontis oralis (NPO) play a critical role in the generation and maintenance of wakefulness as well as active (REM) sleep (AS). We therefore hypothesized that one of the neuronal mechanisms of GABA actions in the NPO to promote wakefulness and suppress AS is due to a direct GABAergic inhibition of NPO neurons that generate AS (AS-generator neurons). However, the anatomical substrate for this inhibition is undetermined. Accordingly, the present study was undertaken to examine whether there is any direct interaction between GABAergic neurons and glutamatergic AS-generator neurons in the NPO. Methods Adult cats were deeply anesthetized and perfused transcardially. The brainstem containing the NPO was removed, postfixed and cut into 15 μm coronal sections with a Reichert-Jung cryostat. The sections were incubated with a mixture of a rabbit polyclonal antibodies against glutamine and GABA following the procedure of double fluorescence immunohistochemistry. Results There was a large number of neuronal somata labeled by anti-glutamine antibody and terminals labeled by anti-GABA antibody in the NPO. These glutamine-positive neurons were medium to large, multipolar cells (> 20 μm), which resemble glutamatergic, AS-generator neurons that have been previously identified in the NPO. Specifically, majority of glutamatergic neuronal somata were closely apposed by multiple GABAergic terminals, indicating that AS-generator neurons in the NPO receive direct GABAergic inputs. Conclusion The present results demonstrate that a direct connection exists between glutamatergic AS-generator neurons and GABAergic processes in the NPO. These data provide the anatomical evidence which supports our hypothesis that the pontine GABAergic control of wakefulness and active sleep is partially mediated via GABAergic processes project to NPO AS-generator neurons that suppress the activity of these cells. Support NS092383

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The lateral hypothalamus to lateral habenula projection, but not the ventral pallidum to lateral habenula projection, regulates voluntary ethanol consumption

Behavioural Brain Research ◽

10.1016/j.bbr.2017.04.029 ◽

2017 ◽

Vol 328 ◽

pp. 195-208 ◽

Cited By ~ 8

Author(s):

Chandni Sheth ◽

Teri M. Furlong ◽

Kristen A. Keefe ◽

Sharif A. Taha

Keyword(s):

Lateral Hypothalamus ◽

Ethanol Consumption ◽

Ventral Pallidum ◽

Lateral Habenula ◽

Voluntary Ethanol Consumption

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Hippocampal efferents to retrosplenial cortex and lateral septum are required for memory acquisition

10.1101/2020.03.23.003996 ◽

2020 ◽

Author(s):

Ashley N Opalka ◽

Dong V Wang

Keyword(s):

Dorsal Hippocampus ◽

Memory Performance ◽

Critical Role ◽

Selective Inhibition ◽

Brain Regions ◽

Retrosplenial Cortex ◽

Contextual Fear Conditioning ◽

Lateral Septum ◽

Contextual Fear ◽

Memory Acquisition

AbstractLearning and memory involves a large neural network of many brain regions, including the notable hippocampus along with the retrosplenial cortex (RSC) and lateral septum (LS). Previous studies have established that the dorsal hippocampus (dHPC) plays a critical role during the acquisition and expression of episodic memories. However, the role of downstream circuitry from the dHPC, including the dHPC-to-RSC and dHPC-to-LS pathways, has come under scrutiny only recently. Here, we employed an optogenetic approach with contextual fear conditioning in mice to determine whether the above two pathways are involved in acquisition and expression of contextual fear memory. We found that a selective inhibition of the dHPC neuronal terminals in either the RSC or LS during acquisition impaired subsequent memory performance, suggesting that both the dHPC-to-RSC and dHPC-to-LS pathways play a critical role in memory acquisition. We also selectively inhibited the two dHPC efferent pathways during memory expression and found a differential effect on memory performance. These results indicate the intricacies of memory processing and that hippocampal efferents to cortical and subcortical regions may be differentially involved in aspects of physiological and cognitive memory processes.

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Distinct properties in ventral pallidum projection neuron subtypes

10.1101/2021.11.15.468637 ◽

2021 ◽

Author(s):

Nimrod Bernat ◽

Rianne Campbell ◽

Hyungwoo Nam ◽

Mahashweta Basu ◽

Tal Odesser ◽

...

Keyword(s):

Gene Expression ◽

Expression Profiles ◽

Expression Patterns ◽

Critical Role ◽

Gene Expression Profiles ◽

Cell Types ◽

Projection Neuron ◽

Brain Regions ◽

Ventral Pallidum ◽

Lateral Habenula

The ventral pallidum (VP), a major component of the basal ganglia, plays a critical role in motivational disorders. It sends projections to many different brain regions but it is not yet known whether and how these projections differ in their cellular properties, gene expression patterns, connectivity and role in reward seeking. In this study, we focus on four major outputs of the VP - to the lateral hypothalamus (LH), ventral tegmental area (VTA), mediodorsal thalamus (MDT), and lateral habenula (LHb) - and examine the differences between them in 1) baseline gene expression profiles using projection-specific RNA-sequencing; 2) physiological parameters using whole-cell patch clamp; and 3) their influence on cocaine reward using chemogenetic tools. We show that these four VP efferents differ in all three aspects and highlight specifically differences between the projections to the LH and the VTA. These two projections originate largely from separate populations of neurons, express distinct sets of genes related to neurobiological functions, and show opposite physiological and behavioral properties. Collectively, our data demonstrates for the first time that VP neurons exhibit distinct molecular and cellular profiles in a projection-specific manner, suggesting that they represent different cell types.

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Selective adaptation to noxious foods by a herbivorous insect

Journal of Experimental Biology ◽

10.1242/jeb.204.19.3355 ◽

2001 ◽

Vol 204 (19) ◽

pp. 3355-3367 ◽

Cited By ~ 1

Author(s):

John I. Glendinning ◽

Stephanie Domdom ◽

Eliza Long

Keyword(s):

Behavioral Response ◽

Aristolochic Acid ◽

Selective Adaptation ◽

Toxic Effects ◽

Herbivorous Insect ◽

Adaptation Process ◽

Gustatory System ◽

Acid Diet ◽

Aversive Taste ◽

Aversive Response

SUMMARYWhen animals repeatedly sample a noxious food over a period of 1–4 days, they can markedly reduce their aversive behavioral response to the diet’s unpleasant taste (e.g. ‘bitterness’) or toxic effects. This long-term adaptation process is selective, however, permitting insects to adapt physiologically to some but not all noxious foods. We hypothesized (i) that the selective nature of this adaptation process stems from the fact that some unpalatable foods are toxic while others are harmless and (ii) that insects have more difficulty adapting to foods that are both unpalatable and toxic. Our model system consisted of Manduca sexta caterpillars and two compounds that taste bitter to humans and elicit an aversive behavioral response in this insect (salicin and aristolochic acid). We found that 2 days of exposure to a salicin diet completely adapted the aversive response of the caterpillars to salicin, but that exposure to an aristolochic acid diet failed to adapt the aversive response to aristolochic acid. We determined that M. sexta could not adapt to the aristolochic acid diet because it lacked mechanisms for reducing the compound’s toxicity. In contrast, the salicin diet did not produce any apparent toxic effects, and the caterpillars adapted to its aversive taste within 12 h of exposure. We also found that the salicin adaptation phenomenon (i) was mediated by the central gustatory system, (ii) generalized to salicin concentrations that were twice those in the adapting diet and (iii) offset spontaneously when the caterpillar was transferred to a salicin-free diet. We propose that toxicity is a more significant barrier to dietary adaptation than ‘bitterness’ in this insect.

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