RESUMO
Homeostatic challenges may alter the drive for social interaction. The neural activity that prompts this motivation remains poorly understood. In the present study, we identify direct projections from the hypothalamic supraoptic nucleus to the cortico-amygdalar nucleus of the lateral olfactory tract (NLOT). Dual in situ hybridization with probes for pituitary adenylate cyclase-activating polypeptide (PACAP), as well as vesicular glutamate transporter (VGLUT)1, VGLUT2, V1a and V1b, revealed a population of vasopressin-receptive PACAPergic neurons in NLOT layer 2 (NLOT2). Water deprivation (48 h, WD48) increased sociability compared to euhydrated subjects, as assessed with the three-chamber social interaction test (3CST). Fos expression immunohistochemistry showed NLOT and its main efferent regions had further increases in rats subjected to WD48 + 3CST. These regions strongly expressed PAC1 mRNA. Microinjections of arginine vasopressin (AVP) into the NLOT produced similar changes in sociability to water deprivation, and these were reduced by co-injection of V1a or V1b antagonists along with AVP. We conclude that, during challenge to water homeostasis, there is a recruitment of a glutamatergic-multi-peptidergic cooperative circuit that promotes social behavior.
Assuntos
Neocórtex , Núcleo Supraóptico , Humanos , Ratos , Animais , Núcleo Supraóptico/metabolismo , Arginina Vasopressina/metabolismo , Bulbo Olfatório , Neocórtex/metabolismo , Ratos Wistar , Vasopressinas/metabolismo , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Comportamento Social , Homeostase , Água/metabolismoRESUMO
The arcuate nucleus of hypothalamus (ARC) integrates circulating factors that signal energy status. The vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) are widely distributed in the periphery and central nervous systems (CNS) and play important roles on energy balance. The present study aimed to investigate the responses of microinjection of VIP and PACAP in the ARC on metabolic changes and food intake. In addition, the activity of neurons in the ARC following intracerebroventricular (ICV) microinjection of these peptides was also evaluated. Microinjection of VIP or PACAP in the ARC decreased fasting-induced hyperphagia and food intake, decreased total lipids, and increased free fatty acids plasma concentrations. VIP microinjection in the ARC induced hyperglycemia and decreased total cholesterol level; and PACAP reduced triglycerides concentration. ICV microinjection of VIP and PACAP enhanced neuronal activation in the ARC, associated with lower fasting-induced hyperphagia and plasma metabolic changes (only VIP). These results suggest that VIP and PACAP play important roles in ARC, inducing hypophagia and peripheral metabolic changes, as hyperglycemia, increased free fatty acids and decreased total lipids plasma levels.
Assuntos
Núcleo Arqueado do Hipotálamo , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Peptídeo Intestinal Vasoativo , Animais , Núcleo Arqueado do Hipotálamo/metabolismo , Comportamento Alimentar , Hipotálamo/metabolismo , Lipídeos/sangue , Neurônios/metabolismo , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/farmacologia , Peptídeo Intestinal Vasoativo/metabolismo , Peptídeo Intestinal Vasoativo/farmacologiaRESUMO
The neuropeptide PACAP, acting as a co-transmitter, increases neuronal excitability, which may enhance anxiety and arousal associated with threat conveyed by multiple sensory modalities. The distribution of neurons expressing PACAP and its receptor, PAC1, throughout the mouse nervous system was determined, in register with expression of glutamatergic and GABAergic neuronal markers, to develop a coherent chemoanatomical picture of PACAP role in brain motor responses to sensory input. A circuit role for PACAP was tested by observing Fos activation of brain neurons after olfactory threat cue in wild-type and PACAP knockout mice. Neuronal activation and behavioral response, were blunted in PACAP knock-out mice, accompanied by sharply downregulated vesicular transporter expression in both GABAergic and glutamatergic neurons expressing PACAP and its receptor. This report signals a new perspective on the role of neuropeptide signaling in supporting excitatory and inhibitory neurotransmission in the nervous system within functionally coherent polysynaptic circuits.
Assuntos
Neurônios GABAérgicos/metabolismo , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/genética , Transdução de Sinais , Animais , Feminino , Masculino , Camundongos , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismoRESUMO
The somatotropic axis (SA) regulates numerous aspects of vertebrate physiology such as development, growth, and metabolism and has influence on several tissues including neural, immune, reproductive and gastric tract. Growth hormone (GH) is a key component of SA, it is synthesized and released mainly by pituitary somatotrophs, although now it is known that virtually all tissues can express GH, which, in addition to its well-described endocrine roles, also has autocrine/paracrine/intracrine actions. In the pituitary, GH expression is regulated by several hypothalamic neuropeptides including GHRH, PACAP, TRH and SST. GH, in turn, regulates IGF1 synthesis in several target tissues, adding complexity to the system since GH effects can be exerted either directly or mediated by IGF1. In reptiles, little is known about the SA components and their functional interactions. The aim of this work was to characterize the mRNAs of the principal SA components in the green iguana and to develop the tools that allow the study of the structural and functional evolution of this system in reptiles. By employing RT-PCR and RACE, the cDNAs encoding for GHRH, PACAP, TRH, SST and IGF1 were amplified and sequenced. Results showed that these cDNAs coded for the corresponding protein precursors of 154, 170, 243, 113, and 131 amino acids, respectively. Of these, GHRH, PACAP, SST and IGF1 precursors exhibited a high structural conservation with respect to its counterparts in other vertebrates. On the other hand, iguana's TRH precursor showed 7 functional copies of mature TRH (pyr-QHP-NH2), as compared to 4 and 6 copies of TRH in avian and mammalian proTRH sequences, respectively. It was found that in addition to its primary production site (brain for GHRH, PACAP, TRH and SST, and liver for IGF1), they were also expressed in other peripheral tissues, i.e. testes and ovaries expressed all the studied mRNAs, whereas TRH and IGF1 mRNAs were observed ubiquitously in all tissues considered. These results show that the main SA components in reptiles of the Squamata Order maintain a good structural conservation among vertebrate phylogeny, and suggest important physiological interactions (endocrine, autocrine and/or paracrine) between them due to their wide peripheral tissue expression.
Assuntos
Hormônio Liberador de Hormônio do Crescimento/genética , Iguanas/genética , Fator de Crescimento Insulin-Like I/genética , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/genética , Somatostatina/genética , Hormônio Liberador de Tireotropina/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Hormônio Liberador de Hormônio do Crescimento/química , Hormônio Liberador de Hormônio do Crescimento/metabolismo , Fator de Crescimento Insulin-Like I/química , Fator de Crescimento Insulin-Like I/metabolismo , Filogenia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/química , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Somatostatina/química , Somatostatina/metabolismo , Hormônio Liberador de Tireotropina/química , Hormônio Liberador de Tireotropina/metabolismoRESUMO
Environmental changes affect gene expression that we addressed in the pituitary, a central regulatory organ at the interface between the central nervous system and the endocrine system. With the aim to reveal effects of changes in the aquatic environment on the expression of hypothalamo-hypophyseal factors, we characterized somatolactin (SL) in Cyprinus carpio. SL, a fish specific pituitary hormone belonging to the prolactin (PRL) superfamily, is involved in background adaptation, osmoregulation, reproduction and fatty acid metabolism. Two sl genes, α and ß, were discovered in carp and transcripts of both were detected in pituitaries. Clearly, expression of slα and slß was modulated significantly in pituitary of male adult carp in response to treatment with ZnCl2 (Zn), but only slß responded to 17ß-estrogen (E2), relative to control carp as shown by RT-qPCR analyses. Furthermore, the amount of mRNA of related factors was assessed revealing variable effects on prl, growth hormone (gh), and factors involved in sl regulation: the pituitary transcription factor pit1 and hypothalamic pituitary adenylase cyclase activating peptide (pacap). In parallel, the physiological response of the experimental animals to Zn or E2 was confirmed by showing a significant increase of metallothionein (mt) or vitellogenin (vg) gene expression in liver, classical sentinels for exposure to heavy metal or estrogens. These data suggest that the sl genes seem to be involved in the response to Zn, as well as to estrogen, and could contribute to evaluate biological relevant changes in the aquatic environment.
Assuntos
Carpas/metabolismo , Estrogênios/farmacologia , Proteínas de Peixes/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Glicoproteínas/genética , Metalotioneína/genética , Hormônios Hipofisários/genética , Vitelogeninas/genética , Zinco/farmacologia , Animais , Sequência de Bases , Carpas/crescimento & desenvolvimento , Proteínas de Peixes/metabolismo , Glicoproteínas/metabolismo , Hormônio do Crescimento/metabolismo , Fígado/metabolismo , Masculino , Metalotioneína/metabolismo , Dados de Sequência Molecular , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Hipófise/metabolismo , Hormônios Hipofisários/metabolismo , Prolactina/metabolismo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência do Ácido Nucleico , Oligoelementos/farmacologia , Vitelogeninas/metabolismoRESUMO
The nerve growth factor (NGF) and other neurotrophins, and the neuropeptides vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) are largely present in human tissue and can exert modulatory activities on nervous, endocrine and immune system functions. NGF, VIP and PACAP receptors are expressed systemically in organisms, and thus these mediators exhibit pleiotropic natures. The human immunodeficiency virus type 1 (HIV-1), the causal agent of the acquired immunodeficiency syndrome (AIDS), infects immune cells, and its replication is modulated by a number of endogenous factors that interact with HIV-1-infected cells. NGF, VIP and PACAP can also affect HIV-1 virus particle production upon binding to their receptors on the membranes of infected cells, which triggers cell signaling pathways that modify the HIV-1 replicative cycle. These molecules exert opposite effects on HIV-1 replication, as NGF and other neurotrophins enhance and VIP and PACAP reduce viral production in HIV-1-infected human primary macrophages. The understanding of AIDS pathogenesis should consider the mechanisms by which the replication of HIV-1, a pathogen that causes chronic morbidity, is influenced by neurotrophins, VIP and PACAP, i.e. molecules that exert a broad spectrum of physiological activities on the neuroimmunoendocrine axis. In this review, we will present the main effects of these two groups of mediators on the HIV-1 replicative cycle, as well as the mechanisms that underlie their abilities to modulate HIV-1 production in infected immune cells, and discuss the possible repercussion of the cross talk between NGF and both neuropeptides on the pathogenesis of HIV-1 infection.
Assuntos
Infecções por HIV/metabolismo , HIV-1/fisiologia , Interações Hospedeiro-Parasita/fisiologia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Peptídeo Intestinal Vasoativo/metabolismo , Replicação Viral/fisiologia , Animais , HumanosRESUMO
The high conservation of the pituitary adenylate cyclase activating polypeptide (PACAP) sequence indicates that this peptide fulfills important biological functions in a broad spectrum of organisms. However, in invertebrates, little is known about its presence and its functions remain unclear. Up to now, in non-mammalian vertebrates, the majority of studies on PACAP have focused mainly on the localization, cloning and structural evolution of this peptide. As yet, little is known about its biological functions as growth factor and immunomodulator in lower vertebrates. Recently, we have shown that PACAP, apart from its neuroendocrine role, influences immune functions in larval and juvenile fish. In this work, we isolated for the first time the cDNA encoding the mature PACAP from a crustacean species, the white shrimp Litopenaeus vannamei, corroborating its high degree of sequence conservation, when compared to sequences reported from tunicates to mammalian vertebrates. Based on this, we have evaluated the effects of purified recombinant Clarias gariepinus PACAP administrated by immersion baths on white shrimp growth and immunity. We demonstrated that PACAP improves hemocyte count, superoxide dismutase, lectins and nitric oxide synthase derived metabolites in treated shrimp related with an increase in total protein concentration and growth performance. From our results, PACAP acts as a regulator of shrimp growth and immunity, suggesting that in crustaceans, as in vertebrate organisms, PACAP is an important molecule shared by both the endocrine and the immune systems.
Assuntos
Proteínas de Artrópodes/genética , Penaeidae/genética , Penaeidae/imunologia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/genética , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/química , Proteínas de Artrópodes/metabolismo , DNA Complementar/genética , DNA Complementar/metabolismo , Escherichia coli/genética , Larva/genética , Larva/crescimento & desenvolvimento , Larva/imunologia , Dados de Sequência Molecular , Penaeidae/crescimento & desenvolvimento , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/química , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Reação em Cadeia da Polimerase/veterinária , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência/veterináriaRESUMO
Pituitary Adenylyl Cyclase-Activating Polypeptide (PACAP) is a neuroactive peptide present in the avian retina where it activates adenylyl cyclase (AC) since early in development via PACAP receptors. The synthesis of cAMP in response to PACAP is observed since embryonic day 8/9 (E8/9). After E12, signaling via PACAP receptors desensitizes, reaching very low levels in the mature tissue. We show here that chronic administration of PACAP in vitro desensitizes PACAP-induced cAMP accumulation, while the administration of the PACAP antagonist (PACAP 6-38) re-sensitizes PACAP receptor/cyclase system in vitro and in vivo. Moreover, a twofold increase in the number of tyrosine hydroxylase positive (THâº) cells is observed after in vivo injection of PACAP6-38. NURR1, a transcription factor associated with the differentiation of dopaminergic cells in the CNS, is present in the chick retina in all developmental stages studied. The presence of NURR1 positive cells in the mature tissue far exceeds the number of TH⺠cells, suggesting that these NURR1-positive cells might have the potential to express the dopaminergic phenotype. Our data show that if PACAP signaling is increased in mature retinas, plastic changes in dopaminergic phenotype can be achieved.
Assuntos
Plasticidade Neuronal/fisiologia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Retina/metabolismo , Animais , Western Blotting , Galinhas , AMP Cíclico , Dopamina , Imuno-Histoquímica , Fenótipo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Growth and mRNA levels of the pituitary adenylate cyclase-activating polypeptide (PACAP) and its related peptide (PRP), and the system controlled by the growth hormone (GH) and insulin-like growth factors (IGFs) were analyzed in pejerrey fry fed with graded levels of dietary lipids: 10% (L10), 13% (L13) and 21% (L21). First, the full sequence of pejerrey PRP-PACAP was obtained by RT-PCR, using primers based on conserved fragments of teleosts PACAP sequences. The growth of the fish at 83 days after hatching (dah) and the GH mRNA levels were not significantly affected by the dietary treatment. Conversely, PRP-PACAP expression significantly decreased with increasing dietary lipids (L10 > L21). While GH receptor (GHR)-I and IGF-I transcripts did not differ among groups, GHR-II transcripts decreased in group L21. IGF-II expression apparently followed the same trend. These results in combination with the lower expression of the anorexigenic PRP-PACAP in fish fed diet L21 and the correlation analysis evidencing a particularly fine tuning of the GH-IGF system in group L13, suggest that this diet may cover the energy demands for growing pejerrey from 27 dah onwards. Our results show for first time in fish a differential response of PRP-PACAP transcripts to dietary manipulations, and confirm the sensitivity of the pejerrey GH-IGF system to changes in diet composition despite the lack of (or in advance to) a clear response of somatic growth.
Assuntos
Gorduras na Dieta/administração & dosagem , Regulação da Expressão Gênica no Desenvolvimento , Hormônio do Crescimento/metabolismo , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Smegmamorpha/crescimento & desenvolvimento , Smegmamorpha/metabolismo , Somatomedinas/metabolismo , Sequência de Aminoácidos , Animais , Aquicultura , Sequência de Bases , Encéfalo/metabolismo , Proteínas de Peixes/química , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Hormônio do Crescimento/genética , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Filogenia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/química , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/genética , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/metabolismo , Distribuição Aleatória , Receptores da Somatotropina/genética , Receptores da Somatotropina/metabolismo , Alinhamento de Sequência/veterinária , Homologia de Sequência de Aminoácidos , Somatomedinas/genéticaRESUMO
Growth hormone-releasing hormone (GHRH) and pituitary adenylate cyclase activating polypeptide (PACAP) regulate development and somatic growth in teleosts; they may be associated with sexual growth dimorphism in the half-smooth tongue sole (Cynoglossus semilaevis). We found that the full-length GHRH and PACAP gene sequences obtained from females and males consist of 4160, 4159, 2425, and 2446 bp, respectively, each of which includes four exons and three introns. When we analyzed normal females and males and extra-large male adults, GHRH and PACAP mRNA were found to be predominantly expressed in the brain; the expression levels were highest in normal males. The extra-large males exhibited the lowest mRNA levels of both GHRH and PACAP. Sex differences in GHRH and PACAP mRNA expression during development were also examined in a full-sib family; GHRH and PACAP mRNA were detected at all 27 times sampled from 10 to 410 days old. The GHRH expression levels in females were significantly higher than in males at most of the stages between 20 and 100 days old, while lower than those of males after 120 days old. Five microsatellite loci were identified in GHRH and PACAP genes. We used these five polymorphic markers to genotype 224 individuals, and no significant differences were found between females and males from the Bohai Sea, the Yellow Sea and hatchery samples.