Search results for "habenula"

Early Commissural Diencephalic Neurons Control Habenular Axon Extension and Targeting.

2016

Summary Most neuronal populations form on both the left and right sides of the brain. Their efferent axons appear to grow synchronously along similar pathways on each side, although the neurons or their environment often differ between the two hemispheres [1–4]. How this coordination is controlled has received little attention. Frequently, neurons establish interhemispheric connections, which can function to integrate information between brain hemispheres (e.g., [5]). Such commissures form very early, suggesting their potential developmental role in coordinating ipsilateral axon navigation during embryonic development [4]. To address the temporal-spatial control of bilateral axon growth, we…

2016

Cytoglobin (Cygb) is a vertebrate globin with so far poorly defined function. It is expressed in the fibroblast cell-lineage but has also been found in neurons. Here we provide, using immunohistochemistry, a detailed study on the distribution of Cygb in the mouse brain. While Cygb is a cytoplasmic protein in active cells of the supportive tissue, in neurons it is located in the cytoplasm and the nucleus. We found the expression of Cygb in all brain regions, although only a fraction of the neurons was Cygb-positive. Signals were of different intensity ranging from faint to very intense. Telencephalic neurons in all laminae of the cerebral cortex, in the olfactory bulb (in particular periglom…

Chronic Stress Modulates Interneuronal Plasticity: Effects on PSA-NCAM and Perineuronal Nets in Cortical and Extracortical Regions.

2018

Chronic stress has an important impact on the adult brain. However, most of the knowledge on its effects is focused on principal neurons and less on inhibitory neurons. Consequently, recent reports have begun to describe stress-induced alterations in the structure, connectivity and neurochemistry of interneurons. Some of these changes appear to be mediated by certain molecules particularly associated to interneurons, such as the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) and components of the perineuronal nets (PNN), specialized regions of the extracellular matrix. These plasticity-related molecules modulate interneuronal structure and connectivity, particularly of …

Acute and chronic nicotine exposures differentially affect central serotonin 2A receptor function : focus on the lateral habenula

2020

Nicotine addiction is a serious public health problem causing millions of deaths worldwide. Serotonin (5-hydroxytryptamine

Genetic inactivation of the sigma-1 chaperone protein results in decreased expression of the R2 subunit of the GABA-B receptor and increased suscepti…

2021

There is a growing body of evidence demonstrating the significant involvement of the sigma-1 chaperone protein in the modulation of seizures. Several sigma-1 receptor (Sig1R) ligands have been demonstrated to regulate the seizure threshold in acute and chronic seizure models. However, the mechanism by which Sig1R modulates the excitatory and inhibitory pathways in the brain has not been elucidated. The aim of this study was to compare the susceptibility to seizures of wild type (WT) and Sig1R knockout (Sig1R−/−) mice in intravenous pentylenetetrazol (PTZ) and (+)-bicuculline (BIC) infusion-induced acute seizure and Sig1R antagonist NE-100-induced seizure models. To determine pos…

Lateral Habenula 5-HT2C Receptor Function Is Altered by Acute and Chronic Nicotine Exposures

2021

Serotonin (5-HT) is important in some nicotine actions in the CNS. Among all the 5-HT receptors (5-HTRs), the 5-HT2CR has emerged as a promising drug target for smoking cessation. The 5-HT2CRs within the lateral habenula (LHb) may be crucial for nicotine addiction. Here we showed that after acute nicotine tartrate (2 mg/kg, i.p.) exposure, the 5-HT2CR agonist Ro 60-0175 (5–640 µg/kg, i.v.) increased the electrical activity of 42% of the LHb recorded neurons in vivo in rats. Conversely, after chronic nicotine treatment (6 mg/kg/day, i.p., for 14 days), Ro 60-0175 was incapable of affecting the LHb neuronal discharge. Moreover, acute nicotine exposure increased the 5-HT2CR-immunoreactive (IR)…

Melatonin formation in different parts of the guinea-pig pineal complex as assessed over 24 hours.

1985

There is morphological evidence that the pineal gland is not a uniformly built organ but rather a complex. In the guinea-pig the gland is 6--7 mm in length and dumbbell-shaped, the proximal part coming into intimate contact with central commissural fibres. The aim of the present 24-hour study was to examine in male guinea-pigs whether the proximal, intermediate and distal areas of the gland are involved in melatonin formation and to compare their rhythmicities. Levels of melatonin in serum and the whole pineal gland as assessed by RIA show day/night ratios of 1 : 1.25 and 1 : 3.3, respectively. Serotonin N-acetyltransferase activity was found to exhibit ratios of 1 : 1.75 (Experiment I) and…

Lateral Habenula contribution in nicotine addiction: Focus on dopamine, GABA and serotonin interactions

2011

Compelling evidence has shown a pivotal role of dopaminergic function in drug addiction. Recently, the Habenula (Hb) has attracted a great deal of attention as another target for nicotine in the brain because of its role in regulating dopamine (DA), gamma-aminobutyric acid (GABA) and serotonin (5-HT) systems. Nicotine acts binding to acetylcholine receptors that are widely distributed in the brain. Interestingly, the receptor subtypes that mediate nicotine withdrawal responses are highly expressed in the Hb. Moreover, the block of habenular nicotinic receptors in animals chronically treated with nicotine enhances withdrawal responses once nicotine is discontinued. Furthermore, it has been s…

Septal complex of the telencephalon of lizards: III. Efferent connections and general discussion.

1998

The projections of the septum of the lizard Podarcis hispanica (Lacertidae) were studied by combining retrograde and anterograde neuroanatomical tracing. The results confirm the classification of septal nuclei into three main divisions. The nuclei composing the central septal division (anterior, lateral, medial, dorsolateral, and ventrolateral nuclei) displayed differential projections to the basal telencephalon, preoptic and anterior hypothalamus, lateral hypothalamic area, dorsal hypothalamus, mammillary complex, dorsomedial anterior thalamus, ventral tegmental area, interpeduncular nucleus, raphe nucleus, torus semicircularis pars laminaris, reptilian A8 nucleus/ substantia nigra and cen…

Sex Differences in the Neuroadaptations of Reward-related Circuits in Response to Subchronic Variable Stress

2018

Women are twice as likely to be diagnosed with major depressive disorder. However, fewer studies in rodent models of depression have used female animals, leading to a relative lack of understanding of the female brain’s response to stress, especially at a neural circuit level. In this study, we utilized a 6-day subchronic variable stress (SCVS) mouse model and measured novelty suppressed feeding as behavioral criteria to evaluate susceptibility to SCVS in male and female mice. First, we showed that SCVS induced a decrease in latency to eat (susceptible phenotype) in female mice, but not in males (resilient phenotype). After determining behavioral phenotypes, we investigated the firing activ…