Altered Neurotrophin, Neuropeptide, Cytokines and Nitric Oxide Levels in Autism

Introduction: Modifications in neurotrophins, neuropeptides, cytokines and nitric oxide (NO) levels in autism may represent different biological aspects of the disease. In the present study we investigate simultaneously all these variables as an attempt to clarify their interrelationships in autism. Methods: Plasma levels of vasoactive intestinal peptide (VIP), neurotrophin-3 (NT-3), cytokines and nitric oxide (NO) were determined in children with DSM-IV autistic disorder (n = 24) and in age- and gender-matched healthy controls (n = 24). VIP, NT-3, IFN-gamma and IL-1 beta levels were measured by ELISA, TNF-alpha, IL-10, IL-6, IL-4, IL-2 were evaluated by flow cytometry, and NO by Griess reaction. Results: Plasma levels of VIP, IFN-gamma and NO were significantly higher and NT-3 plasma levels were significantly lower in children with autism, compared to the healthy subjects. In children with autism there was a positive correlation between plasma levels of NO and IFN-gamma. Discussion: Our results indicate the presence of altered levels of neurotrophin and neuropeptide in infantile autism and provide additional evidence that higher levels of IFN-gamma may be associated with increased oxidative stress in autism.

Phenotypic alterations of neuropeptide Y and calcitonin gene-related peptide-containing neurons innervating the rat temporomandibular joint during carrageenan-induced arthritis

The aim of this study was to identify immunoreactive neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) neurons in the autonomic and sensory ganglia, specifically neurons that innervate the rat temporomandibular joint (TMJ). A possible variation between the percentages of these neurons in acute and chronic phases of carrageenan-induced arthritis was examined. Retrograde neuronal tracing was combined with indirect immunofluorescence to identify NPY-immuno-reactive (NPY-IR) and CGRP-immunoreactive (CGRP-IR) neurons that send nerve fibers to the normal and arthritic temporomandibular joint. In normal joints, NPY-IR neurons constitute 78 +/- 3%, 77 +/- 6% and 10 +/- 4% of double-labeled nucleated neuronal profile originated from the superior cervical, stellate and otic ganglia, respectively. These percentages in the sympathetic ganglia were significantly decreased in acute (58 +/- 2% for superior cervical ganglion and 58 +/- 8% for stellate ganglion) and chronic (60 +/- 2% for superior cervical ganglion and 59 +/- 15% for stellate ganglion) phases of arthritis, while in the otic ganglion these percentages were significantly increased to 19 +/- 5% and 13 +/- 3%, respectively. In the trigeminal ganglion, CGRP-IR neurons innervating the joint significantly increased from 31 +/- 3% in normal animals to 54 +/- 2% and 49 +/- 3% in the acute and chronic phases of arthritis, respectively. It can be concluded that NPY neurons that send nerve fibers to the rat temporomandibular joint are located mainly in the superior cervical, stellate and otic ganglia. Acute and chronic phases of carrageenan-induced arthritis lead to an increase in the percentage of NPY-IR parasympathetic and CGRP-IR sensory neurons and to a decrease in the percentage of NPY-IR sympathetic neurons related to TMJ innervation.

Glucocorticoids are required for meal-induced changes in the expression of hypothalamic neuropeptides

Glucocorticoid deficiency is associated with a decrease of food intake. Orexigenic peptides, neuropeptide Y (NPY) and agouti related protein (AgRP), and the anorexigenic peptide proopiomelanocortin (POMC), expressed in the arcuate nucleus of the hypothalamus (ARC), are regulated by meal-induced signals. Orexigenic neuropeptides, melanin-concentrating hormone (MCH) and orexin, expressed in the lateral hypothalamic area (LHA), also control food intake. Thus, the present study was designed to test the hypothesis that glucocorticoids are required for changes in the expression of hypothalamic neuropeptides induced by feeding. Male Wistar rats (230-280 g) were subjected to ADX or sham surgery. ADX animals received 0.9% NaCl in the drinking water, and half of them received corticosterone in the drinking water (B: 25 mg/L, ADX + B). Six days after surgery, animals were fasted for 16 h and they were decapitated before or 2 h after refeeding for brain tissue and blood collections. Adrenalectomy decreased NPY/AgRP and POMC expression in the ARC in fasted and refed animals, respectively. Refeeding decreased NPY/AgRP and increased POMC mRNA expression in the ARC of sham and ADX + B groups, with no effects in ADX animals. The expression of MCH and orexin mRNA expression in the LHA was increased in ADX and ADX + B groups in fasted condition, however there was no effect of refeeding on the expression of MCH and orexin in the LHA in the three experimental groups. Refeeding increased plasma leptin and insulin levels in sham and ADX + B animals, with no changes in leptin concentrations in ADX group, and insulin response to feeding was lower in this group. Taken together, these data demonstrated that circulating glucocorticoids are required for meal-induced changes in NPY, AgRP and POMC mRNA expression in the ARC. The lower leptin and insulin responses to feeding may contribute to the altered hypothalamic neuropeptide expression after adrenalectomy. (C) 2012 Elsevier Ltd. All rights reserved.

Acute cocaine treatment increases thimet oligopeptidase in the striatum of rat brain

Many studies indicate that thimet oligopeptidase (EC3.4.24.15; TOP) can be implicated in the metabolism of bioactive peptides, including dynorphin 1-8, alpha-neoendorphin, beta-neoendorphin and GnRH. Furthermore, the higher levels of this peptidase are found in neuroendocrine tissue and testis. In the present study, we have evaluated the effect of acute cocaine administration in male rats on TOP specific activity and mRNA levels in prosencephalic brain areas related with the reward circuitry; ventral striatum, hippocampus, and frontal cortex. No significant differences on TOP specific activity were detected in the hippocampus and frontal cortex of cocaine treated animals compared to control vehicle group. However, a significant increase in activity was observed in the ventral striatum of cocaine treated-rats. The increase occurred in both, TOP specific activity and TOP relative mRNA amount determined by real time RT-PCR. As TOP can be implicated in the processing of many neuropeptides, and previous studies have shown that cocaine also alters the gene expression of proenkephalin and prodynorphin in the striatum, the present findings suggest that TOP changes in the brain could play important role in the balance of neuropeptide level correlated with cocaine effects. (C) 2012 Elsevier Inc. All rights reserved.

VIP expression in vessels of the vaginal wall: relationship with estrogen status

Objective Vasoactive intestinal peptide (VIP) is a neuropeptide with elevated expression in regions that control urogenital functions. Estrogen appears to modulate VIP expression in various organs, but this effect has not been demonstrated in the vaginal wall. The aim of this study was to evaluate the influence of estrogen status on VIP expression in vessels of the vaginal wall. Methods Surgical specimens were removed from the vaginal walls of 18 premenopausal women and 12 postmenopausal women who were given surgery for genital prolapse grade I or II. Vaginal specimens were stained with estrogen receptor-alpha (ER-alpha) and VIP antibodies. Levels of follicle stimulating hormone (FSH), estradiol, prolactin, fasting glucose and serum thyroxine stimulating hormone were also measured. Estrogen status was assessed on the basis of FSH and ER-alpha scores. Results The vaginal walls of premenopausal women had significantly higher ER-alpha scores than those of menopausal women (premenopausal group, 3.6 +/- 2.2; menopausal group, 1.4 +/- 1.8; p = 0.01). Premenopausal women also had significantly higher levels of VIP in the vaginal wall than menopausal women (p = 0.02). Increasing age was associated with lower level of VIP staining (odds ratio 0.88; 95% confidence interval 0.78-0.99). Conclusion Levels of ER-alpha and VIP expression in the posterior vaginal wall were higher in premenopausal than in menopausal women, but VIP expression was not associated with estrogen status. Age was an independent predictor of VIP staining in vaginal wall biopsies.

Modeling the Emergence of Circadian Rhythms in a Clock Neuron Network

Circadian rhythms in pacemaker cells persist for weeks in constant darkness, while in other types of cells the molecular oscillations that underlie circadian rhythms damp rapidly under the same conditions. Although much progress has been made in understanding the biochemical and cellular basis of circadian rhythms, the mechanisms leading to damped or self-sustained oscillations remain largely unknown. There exist many mathematical models that reproduce the circadian rhythms in the case of a single cell of the Drosophila fly. However, not much is known about the mechanisms leading to coherent circadian oscillation in clock neuron networks. In this work we have implemented a model for a network of interacting clock neurons to describe the emergence (or damping) of circadian rhythms in Drosophila fly, in the absence of zeitgebers. Our model consists of an array of pacemakers that interact through the modulation of some parameters by a network feedback. The individual pacemakers are described by a well-known biochemical model for circadian oscillation, to which we have added degradation of PER protein by light and multiplicative noise. The network feedback is the PER protein level averaged over the whole network. In particular, we have investigated the effect of modulation of the parameters associated with (i) the control of net entrance of PER into the nucleus and (ii) the non-photic degradation of PER. Our results indicate that the modulation of PER entrance into the nucleus allows the synchronization of clock neurons, leading to coherent circadian oscillations under constant dark condition. On the other hand, the modulation of non-photic degradation cannot reset the phases of individual clocks subjected to intrinsic biochemical noise.

Gastrin-releasing peptide receptor (GRPR) mediates chemotaxis in neutrophils

Neutrophil migration to inflamed sites is crucial for both the initiation of inflammation and resolution of infection, yet these cells are involved in perpetuation of different chronic inflammatory diseases. Gastrin-releasing peptide (GRP) is a neuropeptide that acts through G protein coupled receptors (GPCRs) involved in signal transmission in both central and peripheral nervous systems. Its receptor, gastrin-releasing peptide receptor (GRPR), is expressed by various cell types, and it is overexpressed in cancer cells. RC-3095 is a selective GRPR antagonist, recently found to have antiinflammatory properties in arthritis and sepsis models. Here we demonstrate that i.p. injection of GRP attracts neutrophils in 4 h, and attraction is blocked by RC-3095. Macrophage depletion or neutralization of TNF abrogates GRP-induced neutrophil recruitment to the peritoneum. In vitro, GRP-induced neutrophil migration was dependent on PLC-beta 2, PI3K, ERK, p38 and independent of G alpha i protein, and neutrophil migration toward synovial fluid of arthritis patients was inhibited by treatment with RC-3095. We propose that GRPR is an alternative chemotactic receptor that may play a role in the pathogenesis of inflammatory disorders.

Retinal projections and neurochemical characterization of the pregeniculate nucleus of the common marmoset (Callithrix jacchus)

In mammals, the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) are the main components of the circadian timing system. The SCN is the site of the endogenous biological clock that generates rhythms and synchronizes them to environmental cues. The IGL is a key structure that modulates SCN activity and is responsible for the transmission of non-photic information to the SCN, thus participating in the integration between photic and non-photic stimuli. Both the SCN and IGL receive projections of retinal ganglion cells and the IGL is connected to the SCN through the geniculohypothalamic tract. Little is known about these structures in the primate brain and the pregeniculate nucleus (PGN) has been suggested to be the primate equivalent of the rodent IGL. The aim of this study was to characterize the PGN of a primate, the common marmoset (Callithrix jacchus), and to analyze its retinal afferents. Here, the marmoset PGN was found to be organized into three subsectors based on neuronal size, pattern of retinal projections, and the distribution of neuropeptide Y-, GAD-, serotonin-, enkephalin- and substance P-labeled terminals. This pattern indicates that the marmoset PGN is equivalent to the IGL. This detailed description contributes to the understanding of the circadian timing system in this primate species considering the importance of the IGL within the context of circadian regulation. (C) 2012 Elsevier B.V. All rights reserved.

Effects of thyroid status on NEI concentration in specific brain areas related to reproduction during the estrous cycle

We previously showed that short-term hypo- and hyperthyroidism induce changes in neuropeptide glutamic-acid-isoleucine-amide (NEI) concentrations in discrete brain areas in male rats. To investigate the possible effects of hypo- and hyperthyroidism on NEI concentrations mainly in hypothalamic areas related to reproduction and behavior, female rats were sacrificed at different days of the estrous cycle. Circulating luteinizing hormone (LH), estradiol and progesterone concentrations were measured in control, hypothyroid (hypoT, treated with PTU during 7-9 days) and hyperthyroid (hyperT, l-T4 during 4-7 days) animals. Both treatments blunted the LH surge. Hypo- and hyperthyroidism increased estradiol concentrations during proestrus afternoon (P-PM), although hypoT rats showed lower values compared to control during proestrus morning (P-AM). Progesterone levels were higher in all groups at P-PM and in the hyperT during diestrus morning (D2). NEI concentrations were lower in hypoT rats during the estrous cycle except in estrus (E) in the peduncular part of the lateral hypothalamus (PLH). They were also reduced by both treatments in the perifornical part of the lateral hypothalamus (PeFLH) during P-PM. Hypothyroidism led to higher NEI concentrations during P-PM in the organum vasculosum of the lamina terminalis and anteroventral periventricular nucleus (OVLT+AVPV). The present results indicate that NEI concentration is regulated in a complex manner by hypo- and hyperthyroidism in the different areas studied, suggesting a correlation between NEI values and the variations of gonadal steroid levels during estrous cycle. These changes could be, in part, responsible for the alterations observed in the hypothalamic-pituitary-gonadal axis in these pathologies.