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1.
Nerve agents and some pesticides such as diisopropylfluorophosphate (DFP) cause neurotoxic manifestations that include seizures and status epilepticus (SE), which are potentially lethal and carry long-term neurological morbidity. Current antidotes for organophosphate (OP) intoxication include atropine, 2-PAM and diazepam (a benzodiazepine for treating seizures and SE). There is some evidence for partial or complete loss of diazepam anticonvulsant efficacy when given 30?min or later after exposure to an OP; this condition is known as refractory SE. Effective therapies for OP-induced SE are lacking and it is unclear why current therapies do not work. In this study, we investigated the time-dependent efficacy of diazepam in the nerve agent surrogate DFP model of OP intoxication on seizure suppression and neuroprotection in rats, following an early and late therapy. Diazepam (5?mg/kg, IM) controlled seizures when given 10?min after DFP exposure (“early”), but it was completely ineffective at 60 or 120?min (“late”) after DFP. DFP-induced neuronal injury, neuroinflammation, and neurodegeneration of principal cells and GABAergic interneurons were significantly reduced by early but not late therapy. These findings demonstrate that diazepam failed to control seizures, SE and neuronal injury when given 60?min or later after DFP exposure, confirming the benzodiazepine-refractory SE and brain damage after OP intoxication. In addition, this study indicates that degeneration of inhibitory interneurons and inflammatory glial activation are potential mechanisms underlying these morbid outcomes of OP intoxication. Therefore, novel anticonvulsant and neuroprotectant antidotes, superior to benzodiazepines, are desperately needed for controlling nerve agent-induced SE and brain injury. 相似文献
2.
Methylmercury(II) complexes of the most widely studied antidotes for mercury poisoning have been prepared, and both the water solubility and 1-octanol/water partition coefficients determined for these complexes and the L-cysteine complex. New complexes of N-acetyl-D,L-penicillamine, 2-mercaptosuccinic acid, meso-dimercaptosuccinic acid, and Unithiol have been synthesized and characterized, and are found to have the formulations MeHgSCMe2CH(NHCOMe)CO2H, MeHgSCH(CO2H)CH2CO2H, MeHgSCH(CO2H)CH(CO2H)SHgMe, and Na[MeHgSCH2CH-(SHgMe)CH2SO3], respectively. Trends in octanol/water partition coefficients are consistent with reported studies of the effectiveness of antidotes for MeHg(II) poisoning and redistribution of MeHg(II) on administration of antidotes, particularly for British anti-Lewisite, Unithiol, and meso-dimercaptosuccinic acid. 相似文献
3.
Seeds of Silene coeli-rosa L. were germinated and grown at 20°C in short days of 8 h light from fluorescent and tungsten (F + T) bulbs and 16 h darkness for 28 days (day 0). At 1700 h of day 0, the plants were exposed to 16 h light from T (LD) followed by 8 h F + T, or the same treatment interrupted at 1700 h of day 0 by 20 or 60 min darkness. Plants were exposed to tritiated (methyl-[3 H])-thymidine for 2 h (1645–1845 h) and sampled every 2 h for 24 h. The cell cycle (percentage labelled mitoses method), and changes in cell number were measured in the shoot apical meristems. The cell cycle in the LD, 20 and 60 min dark-interrupted LD (diLD) treatments was 10, 11 and 13 h, respectively. Mean cell generation times were ca 3–5 h longer, suggesting that the shorter cell cycles were transient. The proportions of cells with 2C or 4C amounts of nuclear DNA, indicated that imposition of darkness resulted in a progressive lengthening of G1 from about 3 h in the LD to 7 h in the 60 min diLD treatment. Conversely, G2 shortened from about 4 h in the LD to 3 h in the 60 min diLD treatment. Measurements of labelling index indicated that S-phase was about 1.5 to 2 h in each treatment. The data are discussed in relation to the known inhibitory effect of the diLD treatments on flowering. 相似文献
4.
This study investigates the release characteristics of atrial natriuretic peptide (ANP) from young (10 weeks) and old (22 months) rat atrium. Levels of ANP release from samples of atrium were studied by organ perifusion. Rats were exposed to light:dark (LD) cycles of 12:12 or 18:6 and sacrificed at different zeitgeber time (ZT) points: ZT0, ZT6, ZT8, ZT12, ZT16, and ZT19 for LD 12:12 or ZT0, ZT9, ZT16, ZT18, ZT20, and ZT 21.5 for LD 18:6. The heart was collected, and the right atrium was removed, weighed, and perifused with Krebs-bicarbonate buffer for 100 min, including a period of 50 min for stabilization of secretion rate. ANP concentrations released by atrium did not differ between the two age groups either under LD 12:12 or under LD 18:6, except at the light:dark transition under LD 12:12 conditions where ANP levels were significantly (P < 0.05) lower in young compared to old rats. ANP exhibited daily variations in concentrations under LD 12:12, with a peak during the beginning of photophase (ZT0) in young rats and a peak at the beginning of scotophase (ZT12) in old animals. These variations were strongly modified under LD 18:6, where the pattern of the release exhibited a peak during the light phase at ZT16 in both young and old rats. This strongly suggests that the atrial ANP rhythm is dependent on the environmental light:dark cycle. Moreover, the total ANP levels released by atria in old rats were significantly increased under LD 18:6 compared to standard LD 12:12. This observation strongly suggests that old animals are more sensitive to a photoperiodic change. In conclusion, our results show that ANP concentrations in the rat atrium exhibit daily variations which are significantly affected by the daylength (photoperiod) change in aged rats. 相似文献
5.
Gautam A Gupta A Lomash V Pant SC Vijayaraghavan R 《Indian journal of experimental biology》2010,48(7):752-761
Sulphur mustard, [bis (2-chloroethyl)] sulphide (SM), is a bifunctional alkylating agent. SM forms sulphonium ion in the body which alkylates DNA and several other macromolecules, and induces oxidative stress. Although several antidotes have been screened for the treatment of systemic toxicity of SM in experimental animals none of them are recommended so far. In the search for more effective and less toxic antidotes, various combinations were tried against SM induced toxicity and skin lesions. SM exposed through percutaneous route was used to evaluate the prophylactic efficacy of various combinations. Low dose of DRDE-07 (S-2(2-aminoethylamino) ethyl phenyl sulphide), DRDE-30 [S-2(2-aminoethyl amino) ethyl propyl sulphide], DRDE-35 [S-2(2-aminoethyl amino) ethyl butyl sulphide] with amifostine combinations, were given orally 30 min prior to SM exposure. Significant depletion was observed in body weight, organ body weight index and hepatic GSH and GSSG content in mice after SM exposure. Pretreatment with low dose of different combinations of DRDE-07, DRDE-30 and DRDE-35 with amifostine could recover biochemical alterations and histopathological changes caused by SM exposures. 相似文献
6.
ATSUKO MORIBAYASHI TOSHIHIKO HAYASHI DEMAR TAYLOR HIROMU KURAHASHI MUTSUO KOBAYASHI 《Physiological Entomology》2008,33(1):31-36
Abstract. The effect of photoperiod on pupariation time and the ability to secrete ecdysteroids by the larval ring gland of the flesh fly, Boettcherisca peregrina , are compared among three tropical non-diapausing colonies, Bp (forest), Bp (Luwuk) and Bp (NC) and one temperate diapausing colony of Bp (Tokyo). Non-diapausing colonies do not enter diapause under any photoperiod at 20°C, whereas the Bp (Tokyo) diapausing colony enters diapause at the pupal stage under a short-day photoperiod. The times required for 50% pupariation of Bp (forest), Bp (Luwuk) and Bp (Tokyo) are 34 h, 36 h 20 min and 34 h 40 min under short days (SD), respectively. However, Bp (NC) pupariates in a much shorter time (26 h 10 min) compared with the others. The 50% pupariation times of Bp (NC), Bp (forest) and Bp (Tokyo) under long days (LD) are 27 h, 25 h 50 min and 26 h 40 min, respectively. However, it is much longer in Bp (Luwuk) at 53 h 20 min. The rates of secretion of ecdysteroids by the larval ring glands in vitro in Bp (Tokyo) and Bp (forest) are six- to ten-fold higher under SD (6.00 and 3.69 ng) than under LD (0.60 ng), whereas the ring glands of Bp (Luwuk) and Bp (NC) secrete 3.06 and 8.25 ng ecdysteroids under LD and 5.18 and 10.53 ng under SD, respectively. These results suggest there are at least three different physiological types among non-diapausing colonies of B. peregrina : Bp (forest), Bp (Luwuk) and Bp (NC). 相似文献
7.
Twenty-eight-day-old plants of Silene coeli-rosa L. were maintainedin short days (SD) for 9 d (08) or exposed to 7 longdays (LD), or 7 SD with a 5 min exposure at 1700 h of each dayto far-red (FR), red (R) or 5 min FR/5 min R, or 7 dark-interrupted(di = 17001720 h) LD. Treatments were followed by twofurther SD. The mitotic index and G1 and G2 proportions weremeasured in the shoot apices of plants sampled at 2000 h ofeach day of each replicated treatment. Exposure to 7 LD (= 100per cent flowering) resulted in significant increases, relativeto the SD controls, in both the G2 proportion and the mitoticindex on d 0 to 3, 7 and 8. Five minute FR (= 0 per cent flowering)resulted in cell cycle responses similar to those in LD onlyfrom d 0 to 2. R and FR/R (both = 0 per cent flowering) didnot result in any increases in the G2 proportion in the apexapart from d 3 of FR/R. However 5 min FR/5 min R, and to a lesserextent 5 min R, did result in significant increases in the mitoticindex on d 0, 1, 7, and 8. diLD (= 810 per cent flowering)also prevented any significant increases in the G2 proportionon d 0 to 3, and 5 to 8 but the mitotic index was again higheron these days compared with control data. Thus the transitionto floral growth for 90 per cent of the plants is associatedwith changes in the cell cycle in the shoot apex measured asincreases in the G2 proportion at 2000 h of LD 0 to 3 and 7to 8. Silene coeli-rosa L., cell cycle, flowering, phytochrome, shoot apex 相似文献
8.
Programmed cell death in bacteria: proteic plasmid stabilization systems 总被引:27,自引:6,他引:21
9.
M. TAKAHASHI-DEL-BIANCO A. A. BENEDITO-SILVA M. J. A. HEBLING N. MARQUES M. D. MARQUES 《Physiological Entomology》1992,17(4):377-383
Abstract. Respiratory rates of individual workers of Camponotus rufipes Fabricius (Hymenoptera: Formicidae) were measured at 25C and LD 12:12 h (lights on 06.00 hours), DL 12:12h (lights on 18.00 hours), LL (850 lux) and DD (red light, 20–30 lux), using the micro-Warburg technique. Worker ants were collected from natural nest during the winter of 1987 in a woodland park in the region of Rio Claro, Sāo Paulo, Brazil. The respiration of ants showed a circadian rhythm with acrophase ranging from 20 h 41 min to O1 h 18 min and from 10 h 32 min to 12 h 22 min at LD and DD, respectively. In constant darkness the rhythmometric variables were similar to those presented by ants kept at LD 12:12 h. Under constant light no circadian rhythm in the respiration rates was found. A reduction in the amplitude was observed, indicating an inhibitory effect of this light regime on the respiration process. 相似文献
10.
The adsorption and insertion kinetics for the association of two 34-residue cyclic peptides with phosphocholine membranes have been studied using circular and linear dichroism approaches. The two peptides studied are identical with the exception of two residues, which are both tyrosine in one of the peptides and tryptophan in the other. Both peptides adopt random coil conformations in solution in the absence of membranes and do not aggregate at concentrations below 20 μM. After addition to liposome dispersions, circular dichroism spectroscopy indicated that both peptides undergo an extremely rapid transformation to a β-conformation that remains unchanged throughout the remainder of the experiment. Linear dichroism (LD) spectroscopy was used to study the kinetics of membrane adsorption and insertion. The data were analyzed by nonlinear least squares approaches, leading to identification of a number of bound states and their corresponding LD spectra. Two pseudo-first order processes could be identified that were common to both peptides. The first occurred with a time constant of the order of 1 min and led to a bound state characterized by weak LD signals, with significant bands corresponding to the transitions of aromatic side chains. The second process occurred with an unusually long time constant of between 75 and 100 min, forming a state with considerably stronger positive LD absorbance in the far-ultraviolet region of the spectrum. For the tyrosine-substituted peptide, a third slow process with a long time constant (76 min) could also be delineated and was attributed to rearrangements of the peptide within the membrane. 相似文献
11.
Effects of chronic anabolic steroid treatment on tonic and reflex cardiovascular control in male rats 总被引:2,自引:0,他引:2
Beutel A Bergamaschi CT Campos RR 《The Journal of steroid biochemistry and molecular biology》2005,93(1):43-48
The aim of this study was to analyze the cardiovascular effects of chronic stanozolol administration in male rats. The rats were randomly assigned to one of three groups: (1) control (n=12), (2) chronic treatment with low dose of stanozolol (LD, n=18, 5 mg/kgweek) and; (3) treatment with high dose of stanozolol (HD, n=28, 20 mg/kgweek). Mean arterial pressure (MAP) was higher in both HD (128+/-2.2 mmHg) and LD (126+/-2.5 mmHg) than control (116+/-2 mmHg). The LD group showed an increase in cardiac output (control 121+/-2.5, LD 154+/-5.9 ml/min), whereas in the HD group total peripheral resistance increased (control 1.03+/-0.07, HD 1.26+/-0.07 mmHg/ml/min). Acute sympathetic blockade caused a similar decrease in MAP in all groups. In conscious rats, the baroreflex index for bradycardia (control -3.7+/-0.4, LD -2.0+/-0.1 beat/mmHg) and tachycardia (control -3.6+/-0.3, LD -4.7+/-0.2 beat/mmHg) responses changed only in the LD group. Cardiac hypertrophy was observed in both treated groups (P<0.05). In conclusion, hypertension with differential hemodynamic changes and alterations in the reflex control in heart rate is seen at different stanozolol doses, which may be important variables in the cardiovascular effects of anabolic steroids. 相似文献
12.
13.
This study investigates the release characteristics of neuropeptide Y (NPY) from young (10 weeks) and old (22 months) rat atrium. Levels of NPY release from samples of atrium were studied by organ perifusion. Rats were exposed to light:dark (LD) cycles of 12:12 or 18:6 and sacrificed at different circadian stages: 0, 4, 7, 12, 18, and 20 h after dark onset (HADO) for LD 12:12 or 0, 2, 3.5, 6, 15, and 22 HADO for LD 18:6. The heart was collected, and the right atrium was removed, weighed, and perifused with Krebs-bicarbonate buffer for 100 min, including a period of 50 min for stabilization of secretion rate. NPY concentrations released by atrium did not differ between the two age groups. NPY exhibited daily variations in concentrations in LD 12:12, with a peak during the end of scotophase, at 12 HADO, in both the young and old rats. These variations were strongly modified in LD 18:6, where the pattern of the release exhibited two peaks occurring during the two thirds of dark (3.5 HADO) and light (22 HADO) periods. This strongly suggests that the NPY rhythm is dependent on the environmental light:dark cycle. In this paper we show that NPY concentrations in the rat atrium exhibit daily variations, which are maintained with ageing. Moreover, photoperiod greatly influences NPY levels in the atrium. 相似文献
14.
急危重症眼镜蛇伤大鼠多项凝血指标动态变化 总被引:1,自引:1,他引:0
目的动态观察蛇伤后大鼠多项凝血指标、病理及皮下出血情况的改变,为蛇毒毒理及抗蛇毒制剂的研究提供实验数据。方法将SD大鼠注入2~4 LD50眼镜蛇毒造模,于注毒后不同时段(20~140 min)分别进行凝血功能、肝脏和肾脏病理等检测,处死大鼠后观察注毒部位皮下出血情况。结果大鼠注入4 LD50蛇毒20 min,凝血酶原时间(PT)、部分凝血酶原时间(APTT)延长;40 min时,纤维蛋白原(Fbg)明显下降;40 min后凝血功能逐渐回复至0 min水平。肾脏、肝脏组织见血管扩张、充血明显。注毒部位皮下出血范围于20~80min时最明显。2 LD50剂量组凝血功能的变化与4 LD50组相似,但其Fbg下降程度小于4 LD50组,皮下出血面积较4 LD50组小。结论眼镜蛇毒引起凝血功能改变,且其变化程度与剂量及注入时间密切相关。 相似文献
15.
Various medium compositions (phosphate, 1 to 50 mM; ionic strength, 2.8 to 150 meq/liter) significantly affected Nitrosomonas europaea monochloramine disinfection kinetics, as determined by the Live/Dead BacLight (LD) and propidium monoazide quantitative PCR (PMA-qPCR) methods (lag coefficient, 37 to 490 [LD] and 91 to 490 [PMA-qPCR] mg·min/liter; Chick-Watson rate constant, 4.0 × 10(-3) to 9.3 × 10(-3) [LD] and 1.6 × 10(-3) to 9.6 × 10(-3) [PMA-qPCR] liter/mg·min). Two competing effects may account for the variation in disinfection kinetic parameters: (i) increasing kinetics (disinfection rate constant [k] increased, lag coefficient [b] decreased) with increasing phosphate concentration and (ii) decreasing kinetics (k decreased, b increased) with increasing ionic strength. The results support development of a standard medium for evaluating disinfection kinetics in drinking water. 相似文献
16.
Abstract The Indian meal moth Plodia interpunctella Hübner (Lepidoptera: Pyralidae) diapauses as a last‐instar (fifth) larva. At 30 °C, no larvae enter diapause under any photoperiodic conditions; at 25 °C, the photoperiodic response curve is a long‐day type with a critical length of approximately 13 h light; at 20 °C, diapause is induced moderately even under long days (> 13 h). Cumulative effects of short days or long days on diapause induction are determined by alternate, stepwise and gradually changing regimes of photoperiod at 25 °C. When the larvae are repeatedly exposed to LD 16 : 8 h and LD 12 : 12 h photoperiods every other day, the incidence of diapause is 37%. When the larvae are placed under an LD 16 : 8 h photoperiod for 2 days and then under an LD 12 : 12 h photoperiod for 1 day, it is 38 %. Exposure to an LD 16 : 8 h photoperiod for 1 day and then to an LD 12 : 12 h photoperiod for 2 days induces only 15% diapause. This may indicate that the photoperiodic information is not accumulated in a simple fashion despite the generally accepted hypothesis (i.e. photoperiodic counter). Larvae exposed to an LD 16 : 8 h photoperiod for 5 days after oviposition express a very high incidence of diapause even under short days between an LD 2 : 22 h and LD 12 : 12 h photoperiod. After 10 days exposure to an LD 16 : 8 h photoperiod, however, the short day does not induce diapause strongly. On the other hand, an LD 12 : 12 h photoperiod in the early larval life is highly effective in the induction of diapause. A gradual increase or decrease of photoperiod (2 min day?1) shows that the direction of photoperiodic change does not affect the diapause determination. 相似文献
17.
Luisa María Vera Louise Cairns Francisco Javier Sánchez-Vázquez 《Chronobiology international》2013,30(4):666-681
Behavioral rhythms of the Nile tilapia were investigated to better characterize its circadian system. To do so, the locomotor activity patterns of both male and female tilapia reared under a 12:12 h light-dark (LD) cycle were studied, as well as in males the existence of endogenous rhythmicity under free-running conditions (DD and 45 min LD pulses). When exposed to an LD cycle, the daily pattern of activity differed between individuals: some fish were diurnal, some nocturnal, and a few displayed an arrhythmic pattern. This variability would be typical of the plastic circadian system of fish. Moreover, reproductive events clearly affected the behavioral rhythms of female tilapia, a mouth-brooder teleost species. Under DD, 50% (6 of 12) of male fish showed circadian rhythms with an average period (τ) of 24.1±0.2 h, whereas under the 45 min LD pulses, 58% (7 of 12) of the fish exhibited free-running activity rhythms with an average τ of 23.9±0.5 h. However, interestingly in this case, activity was always confined to the dark phase. Furthermore, when the LD cycle was reversed, a third of the fish showed gradual resynchronization to the new phase, taking 7–10 days to be completely re-entrained. Taken together, these results suggest the existence of an endogenous circadian oscillator that controls the expression of locomotor activity rhythms in the Nile tilapia, although its anatomical localization remains unknown. 相似文献
18.
Genjirou Nishi 《Ichthyological Research》1990,37(2):170-181
Under controlled laboratory conditions, the locomotor activity rhythms of four species of wrasses (Suezichthys gracilis, Thalassoma cupido, Labroides dimidiatus andCirrhilabrus temminckii) were individually examined using an actograph with infra-red photo-electric switches in a dark room at temperatures of 21.3–24.3°C,
for 7 to 14 days. The locomotor activity ofS. gracilis occurred mostly during the light period under a light-dark cycle regimen (LD 12:12; 06:00-18:00 light, 18:00-06:00 dark).
The locomotor activity commenced at the beginning of the light period and continued until a little before the beginning of
dark period. The diel activity rhythm of this species synchronizes with LD. Under constant illumination (LL) this species
shows distinct free-running activity rhythms varying in length from 23 hrs. 39 min. to 23 hrs. 47 min. Therefore,S. gracilis appears to have a circadian rhythm under LL. However, in constant darkness (DD), the activity of this species was greatly
suppressed. All the fish showed no activity rhythms in DD conditions. After DD, the fish showed the diel activity rhythm with
the resumption of LD, but this activity began shortly after the beginning of light period. The fish required several days
to synchronize with the activity in the light period. Therefore,S. gracilis appeared to continue the circadian rhythm under DD. InT. cupido, the locomotor activity commenced somewhat earlier than the beginning of the light period and continued until the beginning
of the dark period under LD. The diel activity rhythm of this species synchronizes with LD. Under LL, four of the five specimens
of this species tested showed free-running activity rhythms for the first 5 days or longer varying in length from 22 hrs.
54 min. to 23 hrs. 39 min. Although the activity of this species was suppressed under DD, two of five fish showed free-running
activity rhythms throughout the experimental period. The lengths of such free-running periods were from 23 hrs. 38 min. to
23 hrs. 50 min. under DD. Therefore, it was ascertained thatT. cupido has a circadian rhythm. InL. dimidiatus, the locomotor activity rhythm under LD resembled that observed inT. cupido. The diel activity rhythm of this species synchronizes with LD. Under LL, four of seven of this species showed free-running
activity rhythms throughout the experimental period. The lengths of such free-running periods were from 23 hrs. 07 min. to
25 hrs. 48 min. Although the activity of this species was suppressed under DD, three of five fish showed free-running activity
rhythms throughout the experimental period. The lengths of such free-running periods were from 23 hrs. 36 min. to 23 hrs.
41 min. under DD. Therefore, it was ascertained thatL. dimidiatus has a circadian rhythm. Almost all locomotor activity of C.temminckii occurred during the light period under LD. The diel activity rhythm of this species coincides with LD. Under LL, two of four
of this species showed free-running activity rhythms throughout the experimental period. The lengths of such free-running
periods were from 23 hrs. 32 min. to 23 hrs. 45 min. Although the activity of this species was suppressed under DD, one of
the four fish showed free-running activity rhythms throughout the experimental period. The length of the free-running period
was 23 hrs. 21 min. under DD. Therefore,C. temminckii appeared to have a circadian rhythm. According to field observations,S. gracilis burrows and lies in the sandy bottom whileT. cupido, L. dimidiatus, andC. temminckii hide and rest in spaces among piles of boulders or in crevices of rocks during the night. It seems that the differences in
nocturnal behavior among the four species of wrasses mentioned above are closely related to the intensity of endogenous factors
in their locomotor activity rhythms. 相似文献
19.
Woolstenhulme MT Bailey BK Allsen PE 《Journal of strength and conditioning research / National Strength & Conditioning Association》2004,18(3):422-425
We measured vertical jump, anaerobic power, and shooting accuracy in 18 Division I women basketball players (age 18-22 years) 6 hours following a morning strength training routine called a lift day (LD) and on a control day in which no strength training was performed. Subjects had been strength trained for 4 weeks prior to testing. The strength training session on lift day was a full-body workout and included 7 exercises performed in 3-6 sets at loads ranging from a 5 to 12 repetition maximum (RM). There were no significant differences in jump height with 2 legs (49.5 +/- 4.8 cm and 49.0 +/- 4.8 cm, LD and control, respectively), relative mean power output over 30 seconds on a Wingate bicycle test (6.4 +/- 0.8 W.kg(-1) and 6.6 +/- 0.7 W.kg(-1), LD and control, respectively), or shooting accuracy over 60 seconds (21.5 +/- 3.8 points/min and 21.3 +/- 4.1 points/min, LD and control, respectively). These data suggest that in collegiate women basketball players, a previous bout of strength training has no negative effect on vertical jump height, anaerobic power, or shooting accuracy. 相似文献
20.
Sue Binkley Karen Mosher Beatrix H. White 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(1):37-42
Summary N-acetyltransferase (NAT) activity in pineal glands exhibits a circadian rhythm with peak activity occurring in the dark-time. We previously showed that inGallus domesticus chicks pretreated with LD12:12, NAT activity was increased by dark exposure (peak dark sensitivity occurred during the expected dark-time) or decreased by light at night (peak light sensitivity occurred early in the night during the time of dark sensitivity). In this study we mapped dark sensitivity vs time (for NAT activity increase in response to 2 h dark pulses), and light sensitivity vs time (for NAT activity decrease in response to 10 min or 30 min light pulses) over a cycle for 3-week old chicks,Gallus domesticus, pretreated with long (LD16:8) or short photoperiod (LD8:16). Sensitivity to light was increased in the second 8 h after L/D by LD8:16. Sensitivity to dark was increased in the first 8 h after L/D by LD16:8.Abbreviations
LD16:8
a light-dark cycle consisting of 16 h of light alternating with 8 h of dark
-
LD8:16
a light-dark cycle consisting of 8 h of light alternating with 16 h of dark
-
DD
constant dark
-
LL
constant light
-
L/D
lights-off
-
D/L
lights-on
-
NAT
pineal serotonin N-acetyltransferase
- NAT
activity is given in nmoles/pineal gland/h
-
chick
used here to denote a young bird of either sex of the speciesGallus domesticus from hatching to three weeks of age 相似文献