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At least 181 records · Page 10Linked to original sources
PubMed2003

LRRN6A/LERN1 (leucine-rich repeat neuronal protein 1), a novel gene with enriched expression in limbic system and neocortex.

Human chromosome 15q24-q26 is a very complex genomic region containing several blocks of segmental duplications to which susceptibility to anxiety disorders has been mapped (Gratacos et al., 2001, Cell, 106, 367-379; Pujana et al., 2001, Genome Res., 11, 98-111). Through an in silico gene content analysis of the 15q24-q26 region we have identifie1d a novel gene, LRRN6A (leucine-rich repeat neuronal 6A), and confirmed its location to the centromeric end of this complex region. LRRN6A encodes a transmembrane leucine-rich repeat protein, LERN1 (leucine-rich repeat neuronal protein 1), with similarity to proteins involved in axonal guidance and migration, nervous system development and regeneration processes. The identification of homologous genes to LRRN6A on chromosomes 9 and 19 and the orthologous genes in the mouse genome and other organisms suggests that LERN proteins constitute a novel subfamily of LRR (leucine-rich repeat)-containing proteins. The LRRN6A expression pattern is specific to the central nervous system, highly and broadly expressed during early stages of development and gradually restricted to forebrain structures as development proceeds. Expression level in adulthood is lower in general but remains stable and significantly enriched in the limbic system and cerebral cortex. Taken together, the confirmation of LRRN6A's expression profile, its predicted protein structure and its similarity to nervous system-expressed LRR proteins with essential roles in nervous system development and maintenance suggest that LRRN6A is a novel gene of relevance in the molecular and cellular neurobiology of vertebrates.

Amino Acid Sequence↗
PubMed1977

Anterograde transneuronal degeneration in the limbic system: clinical-anatomic correlation.

A 64-year-old man with diffuse atherosclerosis developed an organic mental syndrome, followed by hypothalamic symptoms. Autopsy showed an old large cystic infarct involving the left temporal lobe including the hippocampus, and atrophy of the ipsilateral fornix, mammillary body, hypothalamus, mammillothalamic tract, and the anterior thalamic nucleus. The clinical deterioration and pathologic findings may be explained by anterograde transneuronal degeneration within the limbic system following the infarction.

Atrophy↗
PubMed1998

Reduced mRNA expression of neuropeptide Y in the limbic system of tenascin gene disrupted mouse brain.

Tenascin-C (TN), an extracellular matrix glycoprotein which reveals both neurite outgrowth-promoting and growth-inhibiting effects, is generated in the central nervous system. A previous study reported that TN-gene null mutant mice display hyperlocomotion and do not easily habituate to unfamiliar environments. Additionally, these mice display poor appetite, abnormal circadian rhythm and low pregnancy rate. The present study demonstrated that neuropeptide Y (NPY) mRNA expression is reduced in the limbic area of the TN gene-deficient mouse brain as compared to wild-type mice. NPY has been shown to affect emotion, circadian rhythm and food intake, and the present results suggest that the some behavioural abnormalities exhibited by TN-mutant mice may be in part due to the low level of expression of NPY mRNA in the limbic system.

Animals↗
PubMed1982

Somatostatin connections between the hypothalamus and the limbic system of the rat brain.

Somatostatin (SRIF) content of several brain structures was evaluated by radioimmunoassay in rats bearing various types of hypothalamic transections, as well as lesions of the amygdala. Analysis of the regional changes in SRIF concentrations after surgery suggest the following conclusions: (1) hypothalamic somatostatinergic neurons project to the limbic system, with the exception of the amygdaloid nuclei; (2) the olfactory tubercle, the lateral septal nucleus, the habenula and probably the hippocampus receive somatostatin projections from periventricular SRIF-containing cells; (3) somatostatin-containing fibers take a lateral course after leaving periventricular cells and join the medial forebrain bundle; (4) somatostatin innervation of the amygdala seems to be intrinsic.

Amygdala↗
PubMed1990

Sleep deprivation increases dopamine D1 receptor antagonist [3H]SCH 23390 binding and dopamine-stimulated adenylate cyclase in the rat limbic system.

Sleep deprivation induced by the platform technique is considered to be a heavy stressful situation in rats. At the end of the sleep deprivation period (72 h) the rats displayed particular behaviour characterized by wakefulness, a high degree of motor and exploratory activity, increased alertness and reactivity to environmental stimuli. Our previous results indicated that this behaviour was potently antagonized by the administration of the D1-selective antagonist SCH 23390. In this paper we show that concomitantly to this behaviour, an increased number of D1 receptors associated with an increased dopamine-stimulated adenylate cyclase activity is present in the limbic system but not in the striatum of these animals. These data suggest an active role of limbic D1 receptors in the generation of arousal and insomnia related to sleep deprivation induced stress.

Adenylyl Cyclases↗
PubMed1995

Ectopic expression of a bacterial lacZ gene in the limbic system of transgenic mice.

In three independent lines of transgenic mice, a 3.6 kb 5'-flanking sequence of the uroplakin II gene consistently drives the ectopic expression of a bacterial lacZ reporter gene in brain, in addition to its specific expression in the suprabasal layers of the urothelium. The ectopic expression in brain is especially noteworthy insofar as it is confined to structures comprising the limbic system. These findings provide additional evidence that the cells forming such functional systems share specific biochemical properties, and also indicate that this promoter may be useful as a tool for studying the effects of overexpression of proteins in anatomically and functionally defined central nervous system pathways.

Animals↗
PubMed1979

Immuno-electron microscopical demonstration of vasopressin and oxytocin synapses in the limbic system of the rat.

The extensive distribution of exohypothalamic vasopressin or oxytocin containing nerve fibres is thought to be the anatomical basis for the involvement of these neuropeptides in central processes. Following light microscopic observations suggesting that these fibres terminate on other neurons, the present study was undertaken to demonstrate the existence of such endings in the limbic system, which is one of the main target areas for these peptides. For immunoelectron microscopy glutaraldehyde-paraformaldehyde perfused brains of male Wistar rats and Brattleboro rats, homozygous for diabetes insipidus, with and without postfixation in OsO4, were used. Post-embedding staining revealed false positive reaction product on all dense core vesicles, e.g., in the lateral septum. With pre-embedding staining, however, intense and specific reactions were observed for both vasopressin and oxytocin at their sites of production, as well as the neurohypophysis and in the extrahypothalamic limbic brain regions. In the lateral septum and habenular nucleus only vasopressin-containing synapses could be demonstrated, while in the medial nucleus of the amygdala synapses containing either vasopressin or oxytocin were observed. These peptide containing synapses do not seem to differ in any fundamental way from the classical transmitter-containing synapses in the brain.

Amygdala↗
PubMed1996

Hypoperfusion in the limbic system and prefrontal cortex in depression: SPECT with anatomic standardization technique.

UNLABELLED: Depression is a common psychiatric illness, and several reports have described cerebral blood flow (CBF) abnormalities on SPECT studies in affected patients. However, because region of interest analyses were used to determine significant CBF changes in these studies, there were methodological limitations. Therefore, we investigated CBF distribution abnormalities in depression on a pixel-by-pixel basis using SPECT and an anatomic standardization technique that has been commonly used for PET activation studies. METHODS: Eleven patients with unipolar depression, six patients with bipolar depression and nine age-matched normal control subjects underwent HMPAO brain SPECT studies. The radioactivities of SPECT images for each subject were globally normalized to 100 counts/pixel. Then, each SPECT image was transformed for standard brain anatomy using a computerized Human Brain Atlas system. For each group, the mean and variance images were calculated from the standardized anatomic SPECT images, and group comparisons were performed on a pixel-by-pixel basis. RESULTS: Significant decreases in CBF in the prefrontal cortices, limbic systems and paralimbic areas were observed in both depression groups compared with the normal control group. CONCLUSION: Decreases in CBF in these regions may be related to impaired attention as well as cognitive and emotional responses, which have been recognized as usual symptoms in depression. The anatomic standardization technique promises to be useful for group comparison analysis of brain SPECT on a pixel-by-pixel basis for individual neurological and psychiatric diseases.

Aged↗
PubMed1978

The effect of gamma-acetylenic GABA, an enzyme-activated irreversible inhibitor of GABA-transaminase, on dopamine pathways of the extrapyramidal and limbic systems.

gamma-Acetylenic GABA (100 mg/kg i.p.) inhibited GABA-transaminase activity and caused a several-fold increase in the concentration of GABA in rat brain. This increased GABA concentration was associated with a decreased rate of dopamine depletion following alpha-methyl-p-tyrosine treatment and a decrease in homovanillic acid in extrapyramidal and limbic structures suggesting a decrease in dopamine turnover in both pathways. In addition, gamma-acetylenic GABA injected into the ventral mesencephalic tegmentum decreased dopamine turnover in the mesolimbic forebrain. These results are consistent with a modulatory function of GABAergic neurons on extrapyramidal and limbic dopamine pathways. Inhibitory effects on dopaminergic functions of the extrapyramidal and limbic systems were also indicated by the amphetamine and apomorphine-induced ipsilateral turning after unilateral substantia nigral injections of gamma-acetylenic GABA and by the attenuation of dopamine-induced hypermotility after bilateral injections of gamma-acetylenic GABA into the nucleus accumbens.

4-Aminobutyrate Transaminase↗
PubMed2001

Endomorphin1-like immunoreactivity in the limbic system of Syrian hamsters (Mesocricetus auratus).

Recently, endomorphin-1 (Tyr-Pro-Trp-Phe-NH2; EM1), an endogenous peptide that has high affinity and selectivity for the mu-opiate receptor, has been shown to modulate emotional behavior in mice and social behavior in Syrian hamsters. Endomorphin-1 (EM1) is present throughout the central nervous system in rats, mice, and guinea pigs; however, the distribution of EM1 in hamsters has not been described. The purpose of the present study was to investigate the distribution of EM1-like immunoreactivity (EM1L-IR) in the limbic system of Syrian hamsters using immunocytochemistry. Perikarya containing EM1L-IR were present in the anterior area, dorsomedial, ventromedial, periventricular, posterior, and arcuate nuclei of the hypothalamus. Fibers expressing EM1L-IR were present in the nucleus accumbens, caudate putamen, septum, bed nucleus of the stria terminalis, amygdaloid complex, and hypothalamus. The distribution of EM1 suggests a potential endogenous role for this peptide in major processes modulated by opiates, including affective states and social behavior.

Animals↗
PubMed1991

Effects of sleep deprivation on the limbic system and the frontal lobes in affective disorders: a study with Tc-99m-HMPAO SPECT.

We studied 10 patients with melancholia before and after sleep deprivation and 8 controls with Tc-99m-hexamethylpropylenamineoxime (HMPAO) single photon emission computed tomography (SPECT). All depressed subjects showed relative hypoperfusion in the left anterolateral prefrontal cortex under both conditions. Only responders showed relative hyperperfusion in parts of the limbic system and a reduction of blood flow in these regions after sleep deprivation.

Adult↗
PubMed1993

[Effects of morphine on muscarinic receptors in limbic system in acute adjuvant-induced arthritic rats].

To induce arthritis, the adjuvant with heat-killed Mycobacterium tuberculosis was injected into the ankle joint in rats. Local redness, swelling, hotness, pain, and motor dysfunction of the inflamed joint (as well as mental dullness) were observed 48 h after inoculation. At this time, the maximal binding capacity (Bmax) of muscarinic receptors in limbic system was increased, while the dissociation constant (Kd) was unchanged. Injection of morphine (5 mg.kg-1) 3 times within 48 h after the inoculation resulted in a decrease of Bmax and an increase of Kd of M-receptors, together with diminution of pain and disappearance of dullness.

Animals↗
PubMed1993

Identification of a receptor for gamma melanotropin and other proopiomelanocortin peptides in the hypothalamus and limbic system.

Corticotropin (ACTH) and melanotropin (MSH) peptides (melanocortins) are produced not only in the pituitary but also in the brain, with highest concentrations in the arcuate nucleus of the hypothalamus and the commisural nucleus of the solitary tract. We have identified a receptor for MSH and ACTH peptides that is specifically expressed in regions of the hypothalamus and limbic system. This melanocortin receptor (MC3-R) is found in neurons of the arcuate nucleus known to express proopiomelanocortin (POMC) and in a subset of the nuclei to which these neurons send projections. The MC3-R is 43% identical to the MSH receptor present in melanocytes and is strongly coupled to adenylyl cyclase. Unlike the MSH or ACTH receptors, MC3-R is potently activated by gamma-MSH peptides, POMC products that were named for their amino acid homology with alpha- and beta-MSH, but lack melanotropic activity. The primary biological role of the gamma-MSH peptides is not yet understood. The location and properties of this receptor provide a pharmacological basis for the action of POMC peptides produced in the brain and possibly a specific physiological role for gamma-MSH.

Adenylyl Cyclases↗
PubMed2001

Delta 9-tetrahydrocannabinol-induced alterations in limbic system glucose use in the rat.

The effects of Delta9-tetrahydrocannabinol (THC) on neural activity in the rat were investigated using [14C]2-deoxyglucose autoradiography to measure local cerebral glucose use. Overall, THC reduced glucose use at 5 mg/kg and slightly increased it at 1 mg/kg. Significant reductions were seen at the higher dose in regions of the hippocampus and limbic system, and in structures associated with sensory and sensorimotor process ing, consistent with the effects of THC on memory, sensory perception and motor control. Glucose use was increased in the shell of the nucleus accumbens at 1 mg/kg but not reduced at 5 mg/kg. This may reflect increases in activity in mesolimbic reward pathways which at the higher dose are mitigated by reduced glutamatergic outflow from the hippocampus.

Analgesics, Non-Narcotic↗
PubMed1992

Dopamine D1 and opioid receptor binding changes in the limbic system of sleep deprived rats.

Sleep deprivation induced by the platform technique is considered to be a heavy stressful situation in rats. At the end of the sleep deprivation period (72 h) the rat displayed particular behavior characterized by wakefulness, a high degree of motor and exploratory activity, increased alertness and reactivity to environmental stimuli. Our previous results indicated that this behavior was potently antagonized by the administration of the D1 selective antagonist SCH 23390 and by the opioid antagonist naloxone. In this paper we show that concomitantly to this behavior, an increased number of D1 receptors associated with an increased dopamine-stimulated adenylate cyclase activity is present in the limbic system but not in the striatum of these animals. On the contrary, a decreased Bmax of mu and delta opioid receptors was found in the same brain area. These data suggest an active role of limbic dopamine and opioid systems in the generation of arousal and insomnia related to sleep deprivation-induced stress.

Animals↗
PubMed1981

Direct retinal input to the limbic system of the rat.

Retinal projections in rats were studied using anterograde horseradish peroxidase (HRP) tracing and electron microscopic (EM) degeneration. HRP-labeled axons were observed to leave the optic tract in the vicinity of the lateral geniculate nucleus and enter the stria terminalis where they coursed anteriorly to the bed nucleus of the stria terminalis (BNST), and the anterodorsal (TAD) and anteroventral (TAV) thalamic nuclei. After enucleation, selected areas studied with EM confirmed that retinal presynaptic terminals are located in the BNST and TAV. These results support the finding of Conrad and Stumpf that the retina has a direct link to the limbic system.

Animals↗