Neuropeptides in the rat claustrum - An immunohistochemical detection.

Neuropeptides are involved in numerous brain activities and are responsible for a wide spectrum of higher mental functions. The main purpose of this outline structural qualitative study was to identify the possible immunoreactivity of classical neuropeptides, as well as novel ones such as nesfatin-1, phoenixin (PNX), spexin (SPX), neuromedin U (NMU) and respective receptors within the rat claustrum for the first time. The study shows the novel identification of peptidergic neurotransmission in the rat claustrum which potentially implicates a contribution of this neuropeptide to numerous central neurosecretory mechanisms.

Spexin and nesfatin-1-expressing neurons in the male human claustrum.

Neuropeptides are involved in numerous brain activities being responsible for a wide spectrum of higher mental functions. The purpose of this concise, structural and qualitative investigation was to map the possible immunoreactivity of the novel regulatory peptides: spexin (SPX) and nesfatin-1 within the human claustrum. SPX is a newly identified peptide, a natural ligand for the galanin receptors (GALR) 2/3, with no molecular structure similarities to currently known regulatory factors. SPX seems to have multiple physiological functions, with an involvement in reproduction and food-intake regulation recently revealed in animal studies. Nesfatin-1, a second pleiotropic neuropeptide, which is a derivative of the nucleobindin-2 (NUCB-2) protein, is characterized by a wide distribution in the brain. Nesfatin-1 is a substance with a strong anorexigenic effect, playing an important role in the neuronal circuits of the hypothalamus that regulate food intake and energy homeostasis. On the other hand, nesfatin-1 may be involved in several important brain functions such as sleep, reproductive behaviour, cognitive processes, stress responses and anxiety. For the first time we detected and described a population of nesfatin-1 and SPX expressing neurons in the human claustrum using immunohistochemical and fluorescent methods. The study presents the novel identification of SPX and nesfatin-1 immunopositive neurons in the human claustrum and their assemblies show similar patterns of distribution in the whole structure.

Modulatory effect of long-term treatment with escitalopram and clonazepam on the expression of anxiety-related neuropeptides: neuromedin U, neuropeptide S and their receptors in the rat brain.

BACKGROUND: Newly identified multifunctional peptidergic modulators of stress responses: neuromedin U (NMU) and neuropeptide S (NPS) are involved in the wide spectrum of brain functions. However, there are no reports dealing with potential molecular relationships between the action of diverse anxiolytic or antidepressant drugs and NMU and NPS signaling in the brain. The present work was therefore focused on local expression of the aforementioned stress-related neuropeptides in the rat brain after long-term treatment with escitalopram and clonazepam. METHODS: Studies were carried out on adult, male Sprague-Dawley rats that were divided into 3 groups: animals injected with saline (control) and experimental individuals treated with escitalopram (at single dose 5 mg/kg daily), and clonazepam (at single dose 0.5 mg/kg). All individuals were sacrificed under anaesthesia and the whole brain excised. Total mRNA was isolated from homogenized samples of amygdala, hippocampus, hypothalamus, thalamus, cerebellum and brainstem. Real time-PCR method was used for estimation of related NPS, NPS receptor (NPSR), NMU, NMU and receptor 2 (NMUR2) mRNA expression. The whole brains were also sliced for general immunohistochemical assessment of the neuropeptides expression. RESULTS: Chronic administration of clonazepam resulted in an increase of NMU mRNA expression and formation of NMU-expressing fibers in the amygdala, while escitalopram produced a significant decrease in NPSR mRNA level in hypothalamus. Long-term escitalopram administration affects the local expression of examined neuropeptides mRNA in a varied manner depending on the brain structure. CONCLUSIONS: Pharmacological effects of escitalopram may be connected with local at least partially NPSR-related alterations in the NPS/NMU/NMUR2 gene expression at the level selected rat brain regions. A novel alternative mode of SSRI action can be therefore cautiously proposed.

Escitalopram alters local expression of noncanonical stress-related neuropeptides in the rat brain via NPS receptor signaling.

BACKGROUND: Neuropeptide S (NPS) is a multifunctional regulatory factor that exhibits a potent anxiolytic activity in animal models. However, there are no reports dealing with the potential molecular relationships between the anxiolytic activity of selective serotonin reuptake inhibitors (SSRIs) and NPS signaling, especially in the context of novel stress-related neuropeptides action. The present work therefore focused on gene expression of novel stress neuropeptides in the rat brain after acute treatment with escitalopram and in combination with neuropeptide S receptor (NPSR) blockade. METHODS: Studies were carried out on adult, male Sprague-Dawley rats that were divided into five groups: animals injected with saline (control) and experimental rats treated with escitalopram (at single dose 10 mg/kg daily), escitalopram and SHA-68, a selective NPSR antagonist (at a single dose of 40 mg/kg), SHA-68 alone and corresponding vehicle (solvent SHA-68) control. To measure anxiety-like behavior and locomotor activity the open field test was performed. All individuals were killed under anaesthesia and the whole brain was excised. Total mRNA was isolated from homogenized samples of the amygdala, hippocampus, hypothalamus, thalamus, cerebellum, and brainstem. Real-time PCR was used for estimation of related NPS, NPSR, neuromedin U (NMU), NMU receptor 2 (NMUR2) and nesfatin-1 precursor nucleobindin-2 (NUCB2) gene expression. RESULTS: Acute escitalopram administration affects the local expression of the examined neuropeptides mRNA in a varied manner depending on brain location. An increase in NPSR and NUCB2 mRNA expression in the hypothalamus and brainstem was abolished by SHA-68 coadministration, while NMU mRNA expression was upregulated after NPSR blockade in the hippocampus and cerebellum. CONCLUSIONS: The pharmacological effects of escitalopram may be connected with local NPSR-related alterations in NPS/NMU/NMUR2 and nesfatin-1 gene expression at the level of selected rat brain regions. A novel alternative mode of SSRI action can be therefore cautiously proposed.

Effect of Escitalopram on the Number of DCX-Positive Cells and NMUR2 Receptor Expression in the Rat Hippocampus under the Condition of NPSR Receptor Blockade.

BACKGROUND: Neuropeptide S (NPS) is a multifunctional regulatory factor that exhibits a potent anxiolytic activity in animal models. However, there are no reports dealing with the potential molecular interactions between the activity of selective serotonin reuptake inhibitors (SSRIs) and NPS signaling, especially in the context of adult neurogenesis and the expression of noncanonical stress-related neuropeptides such as neuromedin U (NMU). The present work therefore focused on immunoexpression of neuromedin U receptor 2 (NMUR2) and doublecortin (DCX) in the rat hippocampus after acute treatment with escitalopram and in combination with selective neuropeptide S receptor (NPSR) blockade. METHODS: Studies were carried out on adult, male Sprague-Dawley rats that were divided into five groups: animals injected with saline (control) and experimental individuals treated with escitalopram (at single dose 10 mg/kg daily), escitalopram + SHA-68, a selective NPSR antagonist (at single dose 40 mg/kg), SHA-68 alone, and corresponding vehicle control. All animals were sacrificed under halothane anaesthesia. The whole hippocampi were quickly excised, fixed, and finally sliced for general qualitative immunohistochemical assessment of the NPSR and NMUR2 expression. The number of immature neurons was enumerated using immunofluorescent detection of doublecortin (DCX) expression within the subgranular zone (SGZ). RESULTS: Acute escitalopram administration affects the number of DCX and NMUR2-expressing cells in the adult rat hippocampus. A decreased number of DCX-expressing neuroblasts after treatment with escitalopram was augmented by SHA-68 coadministration. CONCLUSIONS: Early pharmacological effects of escitalopram may be at least partly connected with local NPSR-related alterations of neuroblast maturation in the rat hippocampus. Escitalopram may affect neuropeptide and DCX-expression starting even from the first dose. Adult neurogenesis may be regulated via paracrine neuropeptide S and NMU-related signaling.

Spexin-expressing neurons in the magnocellular nuclei of the human hypothalamus.

Neuropeptides are involved in numerous brain activities being responsible for a wide spectrum of higher mental functions. The purpose of this concise, structural and qualitative investigation was to map the possible immunoreactivity of the novel neuropeptide spexin (SPX) within the human magnocellular hypothalamus. SPX is a newly identified peptide, a natural ligand for the galanin receptors (GALR) 2/3, with no molecular structure similarities to currently known regulatory factors. SPX seems to have multiple physiological functions, with an involvement in reproduction and food-intake regulation recently revealed in animal studies. For the first time we describe SPX expressing neurons in the supraoptic (SON) and paraventricular (PVN) nuclei of the human hypothalamus using immunohistochemical and fluorescent methods, key regions involved in the mechanisms of osmotic homeostasis, energy expenditure, consummatory behaviour, reproductive processes, social recognition and stress responses. The vast majority of neurons located in both examined neurosecretory nuclei show abundant SPX expression and this may indirectly implicate a potential contribution of SPX signalling to the hypothalamic physiology in the human brain.

Escitalopram as a modulator of proopiomelanocortin, kisspeptin, Kiss1R and MCHR1 gene expressions in the male rat brain.

Neuropeptides are important, multifunctional regulatory factors of the nervous system, being considered as a novel, atypical sites of antidepressants action. It has already been proven that some of them, such as selective serotonin reuptake inhibitors (SSRI), are able to affect peptidergic pathways in various brain regions. Despite these reports, there is so far no reports regarding the effect of treatment with SSRIs on brain proopiomelanocortin (POMC), kisspeptin, Kiss1R and MCHR1 gene expression. In the current study we examined POMC, kisspeptin, Kiss1R and MCHR1 mRNA expression in the selected brain structures (hypothalamus, hippocampus, amygdala, striatum, cerebellum and brainstem) of rats chronically treated with a 10 mg/kg dose of escitalopram using quantitative Real-Time PCR. Long-term treatment with escitalopram led to the upregulation of MCHR1 expression in the rat amygdala. Kisspeptin mRNA level was also increased in the amygdala, but Kiss1R mRNA expressions were elevated in the hippocampus, hypothalamus and cerebellum. POMC mRNA expressions were in turn decreased in the hippocampus, amygdala, cerebellum and brainstem. These results may support the hypothesis that these neuropeptides may be involved in the site-dependent actions of SSRI antidepressants. This is the first report of the effects of escitalopram on POMC, kisspeptin, Kiss1R and MCHR1 in animal brain. Our findings shed a new light on the pharmacology of SSRIs and may contribute to a better understanding of the alternative, neuropeptide-dependent modes of antidepressant action.

The first identification of nesfatin-1-expressing neurons in the human bed nucleus of the stria terminalis.

Neuropeptides are involved in various brain activities being able to control a wide spectrum of higher mental functions. The purpose of this concise structural investigation was to detect the possible immunoreactivity of the novel multifunctional neuropeptide nesfatin-1 within the human bed nucleus of the stria terminalis (BNST). The BNST is involved in the mechanism of fear learning, integration of stress and reward circuits, and pathogenesis of addiction. Nesfatin-1-expressing neurons were identified for the first time in several regions of the BNST using both immunohistochemical and fluorescent methods. This may implicate a potential contribution of this neuropeptide to the BNST-related mechanisms of stress/reward responses in the human brain.

Effect of long-term treatment with classical neuroleptics on NPQ/spexin, kisspeptin and POMC mRNA expression in the male rat amygdala.

Neuroleptics modulate the expression level of some regulatory neuropeptides in the brain. However, if these therapeutics influence the peptidergic circuits in the amygdala remains unclear. This study specifies the impact profile of the classical antipsychotic drugs on mRNA expression of the spexin/NPQ, kisspeptin-1 and POMC in the rat amygdala. Animals were treated with haloperidol and chlorpromazine for 28 days prior to transcript quantification via qPCR. Haloperidol and chlorpromazine induced a change in the expression of all neuropeptides analyzed. Both drugs led to the decrease of Kiss-1 expression, whereas in POMC and spexin/NPQ their up-regulation in the amygdala was detected. These modulating effects on may represent alternative, so far unknown mechanisms, of classical antipsychotic drugs triggering pharmacological responses.

Quantitative evaluation of aortic arch development using digital-image analysis.

This study was performed on 80 spontaneously aborted human fetuses of a gestational period of between 17 and 27 weeks. The procedure was based on latex filled arteries, which were preserved in formalin, and then later dissected. Data collection was accomplished using digital imaging. The specific measurements of the aortic arch diameter, length and volume were obtained using a computer program, written solely for the purpose of this study. Results indicated that the collected figures correlated with the fetal age through 3 sets of 4-week intervals. Diameter and length of the aortic arch varied from 2.5 to 4.1 mm and from 6.7 to 10.3 mm, respectively. Both parameters showed statistically significant (p<0.05) linear growth and differences between age groups. The volumetric growth of the aortic arch followed a square root function with its values ranging from 35.7 to 136.8 mm3, which were also statistically significant (p < 0.05). The diameter of the aortic isthmus was measured and compared to the diameters of the ascending and descending aorta thus allowing an estimation ratio between those parameters. Concluding analyses suggest that the aortic isthmus becomes narrower during fetal development.

Digital-image analysis of the aortic arch's development and its variations.

The study was performed on 103 human foetuses (58 female, 45 male) spontaneously aborted at between 14 and 30 weeks of gestation. The arteries were filled with latex, preserved in formalin and then dissected under the microscope and digitalised using a camera system. The following measurements were taken with the use of special computer software: the external diameter, the length and the volume of the arch of the aorta. The increase in diameter and length in relation to age corresponded to a linear function with values ranging from 1.77 mm to 4.09 mm for the diameter and from 4.94 mm to 13.31 mm for the length. The increase in volume corresponded to a square root function with values ranging from 13.42 mm3 to 173.96 mm3. Analysis of arch of the aorta variations revealed 11 cases of a common trunk for the brachiocephalic trunk and the left common carotid artery and 7 cases with the left vertebral artery arising directly from the arch of the aorta. In 2 cases the brachiocephalic trunk was absent, the right subclavian artery branching directly from the arch of the aorta at the level of the left subclavian artery or from the descending aorta just below the arterial duct ostium.