48 research outputs found
Antinociceptive Effects of the Essential Oil of Ocimum Basilicum in Mice
No full textBackground: The essential oil of Ocimum basilicum (EOOB) has a pleasant aroma and is known to have antimicrobial and insecticidal activities. In addition, it is used as a pain reliever in folk medicine. However, there are few reports on the antinociceptive activities of EOOB.
Methods: This study examined the antinociceptive effects of EOOB using formalin and a plantar test in mice. In the formalin test, EOOB (50 ㎎/㎏, 100 ㎎/㎏, 150 ㎎/㎏) was administered intraperitoneally and the licking time of the mice was measured. In the plantar test, intraperitoneal EOOB (50 ㎎/㎏, 100 ㎎/㎏) was administered and the withdrawal latency was measured using the Hargreaves method.
Results: In the formalin test, EOOB (50 ㎎/㎏, IP) showed significant decreases in licking time in the second phase. On the other hand, in the plantar test, there were no significant effects in any of the groups examined.
Conclusions: These results support the traditional use of EOOB for the treatment of painful conditions. However, there is a need for more research to determine the active chemical constituents and the precise mechanism
Identification of HMG-5 as a double-stranded telomeric DNA-binding protein in the nematode Caenorhabditis elegans
No full textAbstractMany protein components of telomeres, the multifunctional DNA–protein complexes at the ends of eukaryotic chromosomes, have been identified in diverse species ranging from yeast to humans. In Caenorhabditis elegans, CEH-37 has been identified by a yeast one hybrid screen to be a double-stranded telomere-binding protein. However, the role of CEH-37 in telomere function is unclear because a deletion mutation in this gene does not cause severe telomere defects. This observation raises the possibility of the presence of genetic redundancy. To identify additional double-stranded telomere-binding proteins in C. elegans, we used a different approach, namely, a proteomic approach. Affinity chromatography followed by Finnigan LCQ ion trap mass spectrometer analysis allowed us to identify several candidate proteins. We further characterized one of these, HMG-5, which is encoded by F45E4.9. HMG-5 bound to double-stranded telomere in vitro as shown by competition assays. At least two telomeric DNA repeats were needed for this binding. HMG-5 was expressed in the nuclei of the oocytes and all embryonic cells, but not in the hatched larvae or adults. HMG-5 mainly localized to the chromosomal ends, indicating that HMG-5 also binds to telomeres in vivo. These observations suggest that HMG-5 may participate, together with CEH-37, in early embryogenesis by acting at the telomeres
The convergence of PDF signaling and CRYPTOCHROME in the neuronal network underlying Drosophila circadian behavior
No full textDaily rhythms of behavior are controlled by a circuit of circadian pacemaking neurons. In Drosophila, 150 pacemakers participate in this network, and recent observations suggest the network is composed of heterogeneous oscillators which normally interact and synchronize. Sixteen oscillator neurons (the small and large LNvs) express a neuropeptide called pigment dispersing factor (PDF) whose signaling is required for the synchrony between oscillators. Given the significance of PDF signaling for numerous aspects of behavioral and molecular rhythms, determining precisely where and how signaling via the PDF receptor (PDFR) occurs is now a central question in the field.
In this study, I pursued the expression patterns of PDFR via two independent approaches. I utilized GAL4 mediated rescue of PDFR, and also generated a large transgene of PDFR through recombineering methodology. I found that GAL4-mediated rescue of pdfr phenotypes using a UAS-PDFR transgene is insufficient to provide complete behavioral rescue. In contrast, a ~70 kB PDF receptor (pdfr) transgene does rescue the entire pdfr circadian behavioral phenotype. The transgene (pdfr-myc) is widely but heterogeneously expressed among pacemakers, and also among a limited number of non-pacemakers. My results support an important hypothesis: the small LNv cells directly target a subset of the other crucial pacemaker neurons cells. Furthermore, expression of pdfr-myc confirms an autocrine feedback signaling by PDF back to PDF-expressing cells. Finally, the results present an unexpected PDF receptor site: the large LNv cells appear to target a subset of glia that resides at the base of the eye.
Next, using this authentic pdfr reporter, the 70 kB pdfr-myc, I observed precise coincidence of PDFR expression and high CRYPTOCHROME (CRY) expression, the circadian photoreceptor, within the circadian clock neurons. PDFR and CRY are highly co-expressed in the 5th small LNv, three LNd, and six to seven DN1s. This observation of precise co-expression of these two genes prompted me to test potential genetic interactions of pdf signaling and cry. Flies doubly mutant for pdfr and cry display severely disrupted locomotor rhythms with an absence of both morning and evening anticipatory peaks. Moreover, these double mutant flies were also arrhythmic under constant dark or light conditions, further suggesting the lack of a functional clock. I also observed an unexpected genetic interaction of PDF and CRY signaling in over-expression conditions. An extra copy of pdfr gene in a cryb background causes long period phenotype, whereas an extra copy of pdfr in a wild-type background does not change any aspect of circadian behavior. This suggests that these two signaling pathways are not simply redundancy since over-expression of one signaling cannot replace the lack of the other: instead of restoring normal behavior that genetic combination generates abnormalities in behavior.
Finally, I tested how these behavioral phenotypes can be related to the changes in the cellular properties of the clock network. In pdfr;; cryb double mutants, which display arrhythmic behavior under LD and constant conditions, molecular rhythms were abnormal in a critical subset of clock neurons (the 5th small LNv and all LNd). In these pacemakers, I observed sustained levels of high nuclear PERIOD. I conclude that this arrested PER rhythms in the subset of clock neurons is the principle basis for the lack of circadian coordination of behavior in the double mutant flies. In the gain-of-function of pdfr flies, I observed cell fate changes from PDF-expressing oscillators to PDFR-expressing slow-clock oscillators. When this same phenomenon was studied in a cryb mutant background, I saw clear period extension in the flies\u27 circadian behavior. This is a new finding in the field: that the balance of different clock cell types may be a point of physiological regulation and may affect the period of circadian rhythms.
Overall, this thesis work reveals an unexpected convergence of Cry-mediated and PDF signaling pathways. This convergence is required to support circadian behavioral rhythms, and initiates a possible link between the balance of cell types and behavioral phenotypes
Tissue-specific expression, heat inducibility, and biological roles of two hsp16 genes in Caenorhabditis elegans
No full textAbstractIn this report we have examined two new heat shock protein (HSP16) proteins in the nematode Caenorhabditis elegans encoded by the open reading frames F08H9.3 and F08H9.4. The F08H9.3 and F08H9.4 genes are oriented in the same direction next to each other on the chromosome, not sharing any promoter region, unlike other hsp16 genes that share common promoters in pairs. The F08H9.3 and F08H9.4 proteins were expressed in a tissue-specific manner, unlike the other four HSP16 proteins. F08H9.3 was expressed in the pharynx, and F08H9.4 in the excretory canal and a few neuronal cells. While F08H9.3 was weakly induced by heat shock only in the same tissue as under the normal condition, F08H9.4 was newly induced in the intestine. RNA interference experiments showed that these two proteins are required for survival under the heat shock condition
Pokes, sunburn, and hot sauce:<i>Drosophila</i>as an emerging model for the biology of nociception
No full textA CRY to Rise
No full textLight-sensing CRYPTOCHROME activates the firing of neurons involved in circadian rhythms.</jats:p
PDFR and CRY signaling converge in a subset of clock neurons to modulate the amplitude and phase of circadian behavior in Drosophila.
No full textBACKGROUND:To synchronize their molecular rhythms, circadian pacemaker neurons must input both external and internal timing cues and, therefore, signal integration between sensory information and internal clock status is fundamental to normal circadian physiology. METHODOLOGY/PRINCIPAL FINDINGS:We demonstrate the specific convergence of clock-derived neuropeptide signaling with that of a deep brain photoreceptor. We report that the neuropeptide PDF receptor and the circadian photoreceptor CRYPTOCROME (CRY) are precisely co-expressed in a subset of pacemakers, and that these pathways together provide a requisite drive for circadian control of daily locomotor rhythms. These convergent signaling pathways influence the phase of rhythm generation, but also its amplitude. In the absence of both pathways, PER rhythms were greatly reduced in only those specific pacemakers that receive convergent inputs and PER levels remained high in the nucleus throughout the day. This suggested a large-scale dis-regulation of the pacemaking machinery. Behavioral rhythms were likewise disrupted: in light:dark conditions they were aberrant, and under constant dark conditions, they were lost. CONCLUSIONS/SIGNIFICANCE:We speculate that the convergence of environmental and clock-derived signals may produce a coincident detection of light, synergistic responses to it, and thus more accurate and more efficient re-setting properties
Time preference of headache attack and chronotype in migraine and tension-type headache
No full textMigraine attacks have a time preference of headache attack (TPHA). Chronotype is the propensity for an individual to sleep at a particular time during a 24-h period. However, limited evidence exists regarding the association between TPHA and chronotype in individuals with migraine or tension-type headache (TTH). The aim of the present study is to investigate TPHA and chronotype in individuals with migraine and TTH, which are two of the most common primary headaches. One hundred sixty-nine first-visit migraine and TTH participants were consecutively enrolled. Information on sleep onset time and wake up time on workdays and free days, and TPHA were investigated with a face-to-face interview using a questionnaire booklet. Chronotype was assessed, using the midpoint of sleep on free days, corrected for sleep extension on free days (MSFsc), by subtracting one-half of the average weekly sleep duration. Headache frequency per month, headache intensity, impact of headache, sleep quality, daytime sleepiness, insomnia severity, and mood status were also assessed. Time preference of headache attack was reported for 45.5% and 44.8% of participants with migraine and TTH, respectively. Migraineurs with TPHA had an earlier MSFsc than did migraineurs without TPHA (1:18 a.m. ± 282 min vs. 4:18 a.m. ± 186 min; p = .022). Among migraineurs with TPHA, a later MSFsc was associated with a later preferential time of attack (β = 1.3, 95% confidence interval [CI] = 0.6-2.1, p = .004). A later MSFsc was significantly correlated with a higher headache frequency per month among migraineurs with TPHA (β = 1.9, 95% CI = 0.3-3.4, p = .023), but was not significantly correlated among migraineurs without TPHA (β = 1.4, 95% CI -1.7-4.4, p = .332). Among TTH participants with TPHA, MSFsc was not significantly associated with a preferential time of attack (β = -0.2, 95% CI = -1.0 to 0.6, p = .611). Headache frequency was not associated with MSFsc among TTH participants with TPHA (β = 0.2, 95% CI = -1.2 to 1.6, p = .792) or among TTH participants without TPHA (β = 0.4, 95% CI = -0.5 to 1.3, p = .354). In conclusion, approximately one-half of participants with migraine and TTH reported having TPHA. Migraineurs with TPHA had an earlier chronotype than did migraineurs without TPHA. A later chronotype was associated with increased headache frequency and a later time of attack among migraineurs with TPHA. Among participants with TTH, TPHA and headache frequency were not significantly associated with chronotype.restrictio
Drosophila caspase activity is required independently of apoptosis to produce active TNF/Eiger during nociceptive sensitization
No full textAbstractTumor necrosis factor (TNF) signaling is required for inflammatory nociceptive (pain) sensitization in Drosophila and vertebrates. Nociceptive sensitization in Drosophila larvae following UV-induced tissue damage is accompanied by epidermal apoptosis and requires epidermal-derived TNF/Eiger and the initiator caspase, Dronc. Major gaps remain regarding TNF function in sensitization, including the relationship between apoptosis/tissue damage and TNF production, the downstream signaling in this context, and the target genes that modulate nociceptive behaviors. Here, apoptotic cell death and thermal nociceptive sensitization are genetically and procedurally separable in a Drosophila model of UV-induced nociceptive sensitization. Activation of epidermal Dronc induces TNF-dependent but effector caspase-independent nociceptive sensitization in the absence of UV. In addition, knockdown of Dronc attenuated nociceptive sensitization induced by full-length TNF/Eiger but not by a constitutively soluble form. UV irradiation induced TNF production in both in vitro and in vivo, but TNF secretion into hemolymph was not sufficient to induce thermal nociceptive sensitization. Downstream mediators of TNF-induced sensitization included two TNF receptor-associated factors, a p38 kinase, and the transcription factor nuclear factor kappa B. Finally, sensory neuron-specific microarray analysis revealed downstream TNF target genes induced during thermal nociceptive sensitization. One of these, enhancer of zeste (E(z)), functions downstream of TNF during thermal nociceptive sensitization. Our findings suggest that an initiator caspase is involved in TNF processing/secretion during nociceptive sensitization, and that TNF activation leads to a specific downstream signaling cascade and gene transcription required for sensitization. These findings have implications for both the evolution of inflammatory caspase function following tissue damage signals and the action of TNF during sensitization in vertebrates.</jats:p
