Rapid identification of novel genes expressed in a circadian manner in rat suprachiasmatic nuclei

The circadian clock in mammals is located in the suprachiasmatic nuclei (SCN). There is evidence that changes in gene expression are central to its mechanism. We are engaged in identifying the genes involved. The small size of the SCN, the large number of mammalian genes and the need to identify those differentially expressed over 24 h have required novel experimental procedures. mRNA differential display and an improved tissue micropunching method have been used to examine temporal changes in gene expression in the SCN of rats maintained in constant darkness. Several of the displayed cDNA species were found to be differentially expressed; they show no homology with published sequences. Riboprobes of these cDNA species were used for in situ hybridization. Emulsion-dipped sections confirmed that at least two of these differentially displayed mRNAs are expressed in a circadian manner

Which patients with chronic reflex sympathetic dystrophy are most likely to benefit from physical therapy?

Background: Chronic reflex sympathetic dystrophy (RSD) is a painful and disabling disorder for which no treatment with proven effects exists. Physical therapy (PT) has been demonstrated to be effective for recently diagnosed RSD, but its value in chronic RSD has not yet been studied. Objective: To find predictors for successful use of PT in RSD with regard to (1) function, strength, and mobility and (2) patient satisfaction. Subjects: Fifty-four patients with chronic RSD, age range 21 to 65 years. Methods: All patients were treated in accordance with a standardized PT protocol for at least 6 months. The effects of treatment (functional status, strength, range of motion) and patient satisfaction measures (grade for result, would repeat, global effect) were evaluated at 12 months. Subgroup analyses were performed to find predictors for success of PT. Results: The subgroup analyses revealed that patients with better baseline function (especially of the hands) obtained better results and greater satisfaction. Greater satisfaction was also associated with less baseline pain and higher baseline range of motion and strength (of leg) values. In general, PT did not show large improvements on effect measures, and the patients' mean grade for the result was 3.8 (on a 10-point scale). Conclusions: In overall terms, PT did not influence functional parameters or give satisfaction to patients with chronic RSD in this study. A randomized trial is required to prove or exclude the actual value of PT for these patients

Circadian variation of EAAC1 glutamate transporter messenger RNA in the rat suprachiasmatic nuclei

Using in situ hybridization, we examined temporal changes of the EAAC1 glutamate transporter mRNA within the suprachiasmatic nuclei (SCN) of rats in constant darkness. Film autoradiographs showed that the SCN and supraoptic nuclei (SON) contained a marked density of hybridization signal. Analysis of silver grains per cell in emulsion-dipped sections indicated that cellular expression of EEAC1 mRNA in the SCN was elevated during the latter part of the subjective night and at the beginning of the subjective day, with a peak at circadian time 23.1 as determined by cosinor analysis. The times at which EAAC1 mRNA is highest correspond to the time points at which extracellular glutamate, a neurotransmitter that putatively mediates photic entrainment, has been reported to be low within the SCN. The presence of EAAC1 mRNA in the SCN and SON may partially explain the resistance of these nuclei to glutamate receptor-mediated excitotoxins; furthermore, the raised level preceding subjective dawn in the SCN may ensure sub-toxic levels of extracellular glutamate at the onset of photic stimulation during the LD cycle. In contrast, cellular expression of EAAC1 mRNA in the cingulate cortex and reticular thalamus remained constant at all time points studied. These results suggest that there is circadian control of the EAAC1 mRNA by the clock intrinsic to the SCN

Ananlysis of gonadotrophin-releasing hormone-1 and kisspeptin neuronal systems in the nonphotoregulated seasonally breeding eastern rock elephant-shrew (Elephantulus myurus)

Of the 18 sub-Saharan elephant-shrew species, only eastern rock elephant-shrews reproduce seasonally throughout their distribution, a process seemingly independent of photoperiod. The present study characterizes gonadal status and location/intensity of gonadotrophin-releasing hormone-1 (GnRH-1) and kisspeptin immunoreactivities in this polyovulating species in the breeding and nonbreeding seasons. GnRH-1-immunoreactive (ir) cell bodies are predominantly in the medial septum, diagonal band, and medial preoptic area; processes are generally sparse except in the external median eminence. Kisspeptin-ir cell bodies are detected only within the arcuate nucleus; the density of processes is generally low, except in the septohypothalamic nucleus, ventromedial bed nucleus of the stria terminalis, arcuate nucleus, and internal and external median eminence. Kisspeptin-ir processes are negligible at locations containing GnRH-1-ir cell bodies. The external median eminence is the only site with conspicuously overlapping distributions of the respective immunoreactivities and, accordingly, a putative site for kisspeptin's regulation of GnRH-1 release in this species. In the nonbreeding season in males, there is an increase in the rostral population of GnRH-1-ir cell bodies and density of GnRH-1-ir processes in the median eminence. In both sexes, the breeding season is associated with increased kisspeptin-ir process density in the rostral periventricular area of the third ventricle and arcuate nucleus; at the latter site, this is positively correlated with gonadal mass. Cross-species comparisons lead us to hypothesize differential mechanisms within these peptidergic systems: that increased GnRH-1 immunoreactivity during the nonbreeding season reflects increased accumulation with reduced release; that increased kisspeptin immunoreactivity during the breeding season reflects increased synthesis with increased release

Sociality and the telencephalic distribution of corticotrophin-releasing factor, urocortin 3, and binding sites for CRF type 1 and type 2 receptors: A comparative study of eusocial naked mole-rats and solitary Cape mole-rats

Various aspects of social behavior are influenced by the highly conserved corticotrophin-releasing factor (CRF) family of peptides and receptors in the mammalian telencephalon. This study has mapped and compared the telencephalic distribution of the CRF receptors, CRF1 and CRF2, and two of their ligands, CRF and urocortin 3, respectively, in African mole-rat species with diametrically opposed social behavior. Naked mole-rats live in large eusocial colonies that are characterized by exceptional levels of social cohesion, tolerance, and cooperation in burrowing, foraging, defense, and alloparental care for the offspring of the single reproductive female. Cape mole-rats are solitary; they tolerate conspecifics only fleetingly during the breeding season. The telencephalic sites at which the level of CRF1 binding in naked mole-rats exceeds that in Cape mole-rats include the basolateral amygdaloid nucleus, hippocampal CA3 subfield, and dentate gyrus; in contrast, the level is greater in Cape mole-rats in the shell of the nucleus accumbens and medial habenular nucleus. For CRF2 binding, the sites with a greater level in naked mole-rats include the basolateral amygdaloid nucleus and dentate gyrus, but the septohippocampal nucleus, lateral septal nuclei, amygdalostriatal transition area, bed nucleus of the stria terminalis, and medial habenular nucleus display a greater level in Cape mole-rats. The results are discussed with reference to neuroanatomical and behavioral studies of various species, including monogamous and promiscuous voles. By analogy with findings in those species, we speculate that the abundance of CRF1 binding in the nucleus accumbens of Cape mole-rats reflects their lack of affiliative behavior. © 2015 Wiley Periodicals, Inc

Release from socially induced reproductive suppression in eusocial naked mole-rats (Heterocephalus glaber) is marked by up-regulation of kisspeptin expression in the hypothalamic anteroventral periventricular nucleus

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