Browsing by Subject "Hypothalamus"
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- PublicationOpen AccessCircadian rhythms of clock gene expression in Nile tilapia (Oreochromis niloticus) central and peripheral tissues : Influence of different lighting and feeding conditions(Springer, 2016) Costa, Leandro; Serrano, Ignacio; Sánchez Vázquez, Francisco Javier; López Olmeda, José Fernando; FisiologíaThe present research aimed to investigate the existence of clock gene expression rhythms in tilapia, their endogenous origin, and how light and feeding cycles synchronize these rhythms. In the first experiment, two groups of fish were kept under an LD cycle and fed at two different time points: in the middle of the light (ML) or in the middle of the dark (MD) phase. In the second experiment, fish fed at ML was fasted and kept under constant lighting (LL) conditions for 1 day. In both experiments, the samples from central ( optic tectum and hypothalamus) and peripheral (liver) tissues were collected every 3 h throughout a 24 h cycle. The express10n levels of clock genes bmall a, clockl, per 1 b, cry2a, and cry5 were analyzed by quantitative PCR. All the clock genes analyzed in brain regions showed daily rhythms: clockl, bmall a, and cry2a showed the acrophase approximately at the end of the light phase (ZT 8:43-11:22 h), whereas perlb and cry5 did so between the end of the dark phase and the beginning of the light phase, respectively (ZT 21: 16-4:00 h). These rhythms persisted under constant conditions. No effect of the feeding time was observed in the brain. In the liver, however, the rhythms of clockl and cry5 were influenced by feeding, anda shift was observed in the MD fish group (ZT 3:58 h for clockl and 11 :20 h for cry5). This study provides the first insights into the molecular clock of tilapia, a very important fish species for aquaculture. It also reveals the endogenous origin of clock gene rhythms and the ability of feeding time to shift the phase in sorne clock genes in the peripheral, but not the central, oscillator.
- PublicationOpen AccessGonadotrophin-releasing hormone immunoreactivity in the brain of the tropical freshwater fish, Pygocentrus notatus (Teleostei-Characidae)(Murcia : F. Hernández, 1993) Cáceres-Dittmar, G.; Tapia, F.J.; Guerrero, H. Y.; Paiva, C. L.; Marcano, D.The distribution of GnRH in the brain of the teleost Pygocentrus notatus was demonstrated with the avidin-biotin peroxidase immunocytochemical method using highly specific antibody against synthetic mammalian GnRH. Optimal immunoreaction was obtained using: 1) Bouin's fluid for fixation; 2) repeated incubation with primary antiserum; 3) the use of a detergent in the dilution buffer; 4) the high sensitivity of the avidin-biotin immunoperoxidase method with the cobalt intensification of 3-3'diaminobenzidine tetrahydrochloride; and 5) the use of primary antibody with high specificity. GnRH-immunoreactive (GnRH-ir) in cells andlor axons was observed in al1 main brain regions. In the forebrain, GnRH-ir was located in a network extending from the caudal part of the olfactory bulb to the telencephalon. GnRH-ir fibres were also observed in the optic tectum, cerebellum and hypothalamus. Two groups of neurona1 cell bodies were identified. One group was located in the antero-ventral telencephalon corresponding to the nucleus olfactoretinalis. The second group was found in the rostrodorsal hypothalamus. No GnRH-ir material was detected in the pituitary gland, thus confirming the results of previous studies on brain GnRH-ir distribution obtained by radioimmunoanalysis in this species. These results demonstrate a high degree of similarity between the GnRH systems of P. notatus and other teleost species.
- PublicationOpen AccessHypothalamocerebellar and cerebellohypothalamic projections - circuits for regulating nonsomatic cerebellar activity.(Murcia : F. Hernández, 1994) Dietrichs, E.; Haines, D.E.; Roste, G. K.; Roste, L. S.Cerebellar involvement in visceral and affective responses is known from physiological and behavioral studies, but the pathways involved in these responses have remained enigmatic. Over the last ten years neuroanatomical studies have shown that the cerebellum and hypothalamus are interconnected by direct hypothalamocerebellar and cerebellohypothalamic projections and by a multitude of indirect pathways. The hypothalamocerebellar projection terminates in the cerebellar nuclei and in all layers of the cerebellar cortex as multilayered fibres. This projection is, at least in part, histaminergic. New immunocytochemical experiments indicate that small numbers of hypothalamocerebellar neurones may contain GABA- or glycine-like immunoreactivity. GABA may function as a transmitter in hypothalamocerebellar fibres, probably in conjunction with histamine, but it is not clear whether glycine may also function as a transmitter or only serve metabolic functions. The bidirectional pathways between the cerebellum and hypothalamus may be part of the circuits through which the cerebellum participates in the modulation of a variety of nonsomatic events. In addition, new observations on patients with well localized cerebellar lesions reveal simultaneous somatic and visceral dysfunction. Recent research on direct hypothalamocerebellar pathways and on other connections between hypothalamus and cerebellum is reviewed. It is hypothesized that the cerebellum may act as a general modulator and coordinator of a wide range of central nervous activities, somatic as well as nonsomatic.
- PublicationOpen AccessInvolvement of neuropeptides in the regulation of growth, structure and function of the adrenal cortex(Murcia : F. Hernández, 1993) Malendowicz, L.K.Current data on the influence of neuropeptides on the growth, structure and function of cells comprising the hypothalamo-pituitaq-adrenal axis were presented and discussed. The action of vasopressin, oxytocin, neurotensin, bombesin, neuropeptide Y, substance P and VTP have been evaluated. The hypothesis has been introduced that in vivo effect of some neuropeptides on the structure and function of the adrenal cortex is mediated by vasopressin.
- PublicationOpen AccessNeuromedins and their involvement in the regulation of growth, structure and function of the adrenal cortex(Murcia : F. Hernández, 1994) Malendowicz, L.K.; Markowska, A.Current data on the synthesis and the mechanism of action of neuromedins on adrenal cortex are presented. The localization of these biologicallyactive peptides in all components of the hypothalamopituitary- adrenal axis as well as their action on the adrenal cortex both in vivo and in vitro suggest their involvement in the regulation of growth, structure and function of the adrenal cortex. Neuromedins may exert both direct and indirect effect on the adrenal cortex. Direct effect is proven by the stimulation of glucocorticoid synthesis by adrenocortical cells in culture (NMK, NML) while indirect effects may be mediated by ACTH, vasopressin (aldosterone secretagogue effect) and angiotensin (prompt proliferative response) or by substances of medullary origin. The last mechanism of action is well documented for NMU.
- PublicationOpen AccessNeuropeptide Y-related peptides and hypothalamo-pituitary-adrenal axis function(Murcia : F. Hernández, 1996) Malendowicz, L.K.; Markowska, A.; Zabel, M.Current data on the localization of neuropeptide Y-related peptides in the hypothalamo-pituitaryadrenal gland (HPA) axis as well as the effects of these peptides on the function of cells comprising HPA axis are presented and discussed. The action of neuropeptide Y. peptide YY, and pancreatic polypeptide on HPA axis are evaluated. Moreover, we report the presence of pancreatic polypeptide immunoreactivity in subset of chromaffin cells in the medulla of rat adrenal gland.
- PublicationOpen AccessNitric oxide in the stress axis(Murcia : F. Hernández, 1998) Lopez-Figueroa, M.O.; Day, H.E.W.; Akil, H.; Watson, S.J.In recent years nitric oxide (NO) has emerged as a unique biological messenger. NO is a highly diffusible gas, synthesized from L-arginine by the enzyme nitric oxide synthase (NOS). Three unique subtypes of NOS have been described, each with a specific distribution profile in the brain and periphery. NOS subtype I is present, among other areas, in the hippocampus, hypothalamus, pituitary and adrenal gland. Together these structures form the limbichypothalamic- pituitary-adrenal (LHPA) or stress axis, activation of which is one of the defining features of a stress response. Evidence suggests that NO may modulate the release of the stress hormones ACTH and corticosterone, and NOS activity and transcription is increased in the LHPA axis following various stressful stimuli. Furthermore, following activation of the stress axis, glucocorticoids are thought to down-regulate the transcription and activity of NOS via a feedback mechanism. Taken together, current data indicate a role for NO in the regulation of the LHPA axis, although at present this role is not well defined. It has been suggested that NO may act as a cellular communicator in plasticity and development, to facilitate the activation or the release of other neurotransmitters, to mediate immune responses, andlor as a vasodilator in the regulation of blood flow. In the following review we summarize some of the latest insights into the function of NO, with special attention to its relationship with the LHPA axis.
- PublicationOpen AccessRadial derivatives of the mouse ventral pallium traced with Dbx1-LacZ reporters(Elsevier, 2015-12-31) Puelles, Luis; Medina, Loreta; Borello, Ugo; Teissier, Anne; Pierani, Alessandra; Rubenstein, John L.R.; Legaz Pérez, Isabel; Ciencias SociosanitariasThe progeny of Dbx1-expressing progenitors was studied in the developing mouse pallium, using two transgenic mouse lines: (1) Dbx1nlslacZ mice, in which the gene of the β-galactosidase reporter (LacZ) is inserted directly under the control of the Dbx1 promoter, allowing short-term lineage tracing of Dbx1-derived cells; and (2) Dbx1CRE mice crossed with a Cre-dependent reporter strain (ROSA26loxP-stop-loxP-LacZ), in which the Dbx1-derived cells result permanently labeled (Bielle et al., 2005). We thus examined in detail the derivatives of the postulated longitudinal ventral pallium (VPall) sector, which has been defined among other features by its selective ventricular zone expression of Dbx1 (the recent ascription by Puelles, 2014 of the whole olfactory cortex primordium to the VPall was tested). Earlier notions about a gradiental caudorostral reduction of Dbx1 signal were corroborated, so that virtually no signal was found at the olfactory bulb and the anterior olfactory area. The piriform cortex was increasingly labeled caudalwards. The only endopiriform grisea labeled were the ventral endopiriform nucleus and the bed nucleus of the external capsule. Anterior and basolateral parts of the whole pallial amygdala also were densely marked, in contrast to the negative posterior parts of these pallial amygdalar nuclei (leaving apart medial amygdalar parts ascribed to subpallial or extratelencephalic sources of Dbx1-derived GABAergic and non-GABAergic neurons). Alternative tentative interpretations are discussed to explain the partial labeling obtained of both olfactory and amygdaloid structures. This includes the hypothesis of an as yet undefined part of the pallium, potentially responsible for the posterior amygdala, or the hypothesis that the VPall may not be wholly characterized by Dbx1 expression (this gene not being necessary for VPall molecular distinctness and histogenetic potency), which would leave a dorsal Dbx1-negative VPall subdomain of variable size that might contribute partially to olfactory and posterior amygdalar structures.
- PublicationOpen AccessSympathetic nervous system contributes to orthodontic tooth movement by central neural regulation from hypothalamus(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Cao, Haifeng; Fang, Bing; Wang, Xudong; Zhou, YanhengOrthodontic tooth movement (OTM) is a specific treatment of malocclusion, whose regulation mechanism is still not clear. This study aimed to reveal the relationship between the sympathetic nervous system (SNS) and OTM through the construction of an OTM rat model through the utilization of orthodontic nickeltitanium coiled springs. The results indicated that the stimulation of SNS by dopamine significantly promote the OTM process represented by the much larger distance between the first and second molar compared with mere exertion of orthodontic force. Superior cervical ganglionectomy (SCGx) can alleviate this promotion effect, further proving the role of SNS in the process of OTM. Subsequently, the ability of orthodontic force to stimulate the center of the SNS was visualized by the tyrosin hydroxylase (TH) staining of neurons in ventromedial hypothalamic nucleus (VMH) and arcuate nucleus (ARC) of the hypothalamus, as well as the up-regulated expression of norepinephrine in local alveolar bone. Moreover, we also elucidated that the stimulation of SNS can promote osteoclast differentiation in periodontal ligament cells (PDLCs) and bone marrow-derived cells (BMCs) through regulation of receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) system, thus promoting the OTM process. In conclusion, this study provided the first evidence for the involvement of the hypothalamus in the promotion effect of SNS on OTM. This work could provide a novel theoretical and experimental basis for further understanding of the molecular mechanism of OTM.