Descending influences from nucleus raphe magnus on fusimotor neurone activity in rats

1. 1.Single fusimotor fibres were isolated in the ventral roots of lumbosacral segments of urethane-anaesthetized rats, and effects of electrical stimulation of the nucleus raphe magnus (NRM) on their spontaneous activity were investigated. The experiments were carried out in rats whose bilateral preoptic and anterior hypothalamic regions (PO/AH) were electrolytically destroyed to eliminate the influences of these regions to fusimotor activity.

2. 2.Of 44 fusimotor fibres studied, 38 (86%) were found to be affected by NRM stimulation. The effects of NRM stimulation were classified according to their response pattern: primary depression (D-type, n = 24), facilitation followed by depression (F-D-type, n = 5) and primary facilitation (F-type, n = 8). The most predominant effect of NRM stimulation upon fusimotor activity was characterized by a strong depression followed by a complete cessation of firing lasting either for a short period or for more than 30 min (D- and F-D-type).

3. 3.In three fusimotor fibres studied in the different preparations, it was observed that a NRM-evoked depression response was blocked by an intraperitoneal administration of a serotonin antagonist, p-chlorophenylalamine (p-CPA) (10 mg/kg).

4. 4.The results indicate that the NRM exerts descending inhibitory or facilitatory influences on fusimotor neurones, and suggest that cold shivering is controlled by modulating fusimotor neurone activity via the serotonergic raphe-signal pathways.

大鼠正中视前核注射血管紧张素Ⅱ(ANGⅡ)对某些肾脏功能指标的影响

目的：探讨大鼠正中视前核注射血管紧张素Ⅱ（ANGⅡ）对某些肾脏功能指标的影响。方法：健康雄性SD大鼠56只随机分为4组（n=14）：①人工脑脊液组：正中视前核（MnPO）先注射人工脑脊液（aCSF）0.25 μl,20 min后再注射0.25 μl,②血管紧张素Ⅱ组：MnPO先注射aCSF 0.25μl,20 min后再注射内含20 ng血管紧张素Ⅱ（AngⅡ）溶液0.25μl,③洛沙坦预处理组：MnPO先注射内含5μg洛沙坦（Losartan）溶液0.25μl,20 min后再注射20 ng血管紧张素Ⅱ溶液0.25μl,④洛沙坦组：MnPO先注射内含5μg洛沙坦溶液0.25μl,20 min后再注射aCSF 0.25μl。每组取7只大鼠在注射前、注射后20 min、40 min、60 min、120 min检测尿钠浓度,另7只大鼠注射1 h后处死动物,取肾脏,检测各组大鼠肾组织一氧化氮（NO）含量和一氧化氮合酶（NOS）活性。结果：52只大鼠进入结果分析,与人工脑脊液组相比,血管紧张素Ⅱ组肾脏NO与NOS活性升高,1 h肾排钠量明显升高;与洛沙坦预处理组相比,血管紧张素Ⅱ组肾脏NO与NOS活性升高,1 h肾排钠量也明显升高。结论：AngⅡ作用于MnPO后,肾促钠排泄反应增强,肾皮质NO水平升高,NOS活性增强,洛沙坦预处理可下调AngⅡ在肾脏诱导的上述变化。     

Menstrual Phase Response to Nocturnal Light

The aims of the study were to test whether nocturnal white light can normalize menstrual cycles in oligomenorrheic women, and whether the phase of the menstrual cycle in which light is given is important for the shortening effect. Twenty-five women with long menstrual cycles (35.9–53.4 days on average) were treated for 1–3 cycles, each of which was preceded and followed by at least two untreated cycles. Treatments were 100 watt bedside lights administered for 5 consecutive nights. They centered at three different phases of the menstrual cycle: 6–7th, 14–17th or 23–25th days of the treated cycle (early, middle or late treatment, respectively). On average, the treatment cycle lengths were modestly, but significantly reduced compared to the duration of baseline cycles (more than 11 %). The difference in the effects of the early, middle and late treatment was not significant. However, if middle or late treatments were administered in the latter half of the interval between the menstrual cycle onset and probable time of ovulation, reductions of the treated cycle length were substantial (more than 20 %, resulting in cycles less than 33 days on average; p < 0.001). Other treatments produced only weak (up to 7 %), if any, cycle reductions. Moreover, we found a strong correlation (p < 0.001) between the duration of baseline cycle and differential effect of middle treatment (compared to early or late treatment). Middle treatments reduced treated cycle duration to the normal range in the subjects with shorter mean baseline cycles (<42 days), while in the subjects with longer duration of baseline cycle the shortening effect was produced by late treatments (p = 0.005 and p = 0.001, respectively). The results support the suggestion that a bedside lamp used on nights prior to ovulation can cause reduction of long menstrual cycles.     

儿童孢子丝菌病的临床分析及致病菌的基因型检测

目的 对吉林省扶余县35例儿童孢子丝菌病进行临床分析并对部分菌株进行基因测定,了解该地区孢子丝菌病的致病菌菌株基因是否发生变异而致致病力增强及发病率增高.方法 收集2011年1月1日～4月30日来自扶余县就诊于我科并确诊为孢子丝菌病的患儿35例,进行临床分析;从中选取8株菌,对其核糖体保守区及内转录间隔区(ITS)、非转录间隔区(NTS)区进行基因测定,了解基因水平上的异同.结果 8株孢子丝菌菌株中5株NTS区可见较大范围的碱基缺失.结论 吉林省扶余县孢子丝菌菌株可能由于NTS区碱基较大范围缺失而致致病力增强,导致该地区短时间内发病率增高.     

Clustered and interspersed repetitive DNA sequence family of Chironomus. The nucleotide sequence of the Cla-elements and of various flanking sequences

The nucleotide sequence of more than 30 cloned members of the clustered and interspersed repetitive Cla-sequence family present in the genome of various chironomids has been determined. In four cloned Cla-element clusters, the 5' and 3'-flanking sequences including the junctions between the Cla-element clusters and the flanking sequences were also sequenced. The repetitive Cla-elements, which are able to transpose under certain circumstances, have a monomer length ranging from 110 to 119 base-pairs, are very A + T-rich (greater than 80% A + T) and display numerous palindromic sequences. The Cla-elements are organized in small (4 elements) to medium-sized (greater than 30 elements) tandem repetitive clusters, which are dispersed over more than 200 sites of the chromosomes of Chironomus thummi thummi, including the non-transcribed spacer of the ribosomal DNA repeating unit. The tandem repetitive Cla-elements show anomalous behaviour during high-percentage polyacrylamide gel electrophoresis, indicating a bent or globular conformation. The flanking sequences are also repetitive, but the sequenced parts did not reveal any tandem repetitive arrangement. Near the junctions of the Cla-element clusters and the flanking sequences, short duplications are found, ranging from 5 to 12 bases, present in both sides of the Cla-element clusters. The Cla-elements might be involved in the hybrid dysgenesis phenomenon that is observed after crossings between the two subspecies Ch. th. thummi and Ch. th. piger.     

Nest thermoregulation in Vespa simillima, V.tropica and V.analis

Abstract. 1. Nest thermoregulation follows a similar pattern in Vespa simillima Smith and V. tropica L. There is a gradual decline in the daily fluctuations of nest temperature to a constant steady state which is maintained during the production of the first sexuals, followed by a sudden loss of stability at the end of the colony cycle.
2. The larvae are not major producers of heat, as they are unable to raise their body temperature by more than 1–2°C above ambient. However, they act as heat reservoirs and providers of food in the form of larval secretions. This feeding may allow workers to raise their body temperature during non-foraging periods.
3. The adults are capable of raising their body temperature many degrees above ambient and the presence of even one adult, in this case a V.analis F. mother queen, was able to raise the nest temperature.
4. Supplementary carbohydrate food promotes thermogenesis and enhances colony development.     

Functional Mapping of Dorsal and Median Raphe 5-Hydroxytryptamine Pathways in Forebrain of the Rat Using Microdialysis

Abstract: Recent neurochemical studies of the properties of 5-hydroxytryptamine (5-HT) pathways arising from the dorsal raphe nucleus (DRN) and median raphe nucleus (MRN) have measured extracellular 5-HT in brain regions with reported preferential DRN or MRN 5-HT inputs. Here, we have tested whether electrical stimulation of the DRN and MRN releases 5-HT in rat forebrain regions in a pattern that fits the reported distribution of DRN/MRN pathways. The effect on extracellular 5-HT of electrical stimulation (5 Hz, 300 µA, 20 min) of the DRN, and then MRN, was determined in six regions of the anaesthetised rat. Stimulation of the DRN evoked a short-lasting but clear-cut release of 5-HT (+70–100%) in regions (frontal cortex, dorsal striatum, globus pallidus, and ventral hippocampus) reported to receive a 5-HT projection from the DRN. Regions receiving an MRN innervation (dorsal hippocampus, medial septum, and ventral hippocampus) released 5-HT (+70–100%) in response to MRN stimulation. Regions reported to receive a preferential DRN innervation (frontal cortex, dorsal striatum, and globus pallidus) did not respond to MRN stimulation. Of two regions (dorsal hippocampus and medial septum) reported to receive a preferential MRN innervation, one did not respond to DRN stimulation (dorsal hippocampus) although the other (medial septum) did. In summary, electrical stimulation of the DRN and MRN released 5-HT in a regionally specific pattern. With the exception of one region (medial septum), this pattern of release bears a strong relationship to the distribution of 5-HT projections from the DRN and MRN reported by anatomical studies. The combination of raphe stimulation with microdialysis may be a useful way to study the in vivo neurochemistry of DRN/MRN 5-HT pathways.     

Climate change: is the dark Soay sheep endangered?

It was recently reported that the proportion of dark-coloured Soay sheep (Ovis aries) in the Hebrides has decreased, despite the fact that dark sheep tend to be larger than lighter sheep, and there exists a selective advantage to large body size. It was concluded that an apparent genetic linkage between loci for the coat colour polymorphism and loci with antagonistic effects on body size explained the decrease. Those results explain why the proportion of dark animals is not increasing, but not why it is decreasing. Between 1985 and 2005 there was a significant increase in mean ambient temperature near the islands. We suggest that, while in the past a dark coat has offset the metabolic costs of thermoregulation by absorbing solar radiation, the selective advantage of a dark coat may be waning as the climate warms in the North Atlantic. In parallel, Bergman''s rule may be operating, reducing the selective advantage of large body size in the cold. Either or both of these mechanisms can explain the decrease in the proportion of dark-coloured larger sheep in this population in which smaller (and light-coloured) sheep should be favoured by their lower gross energy demand. If environmental effects are the cause of the decline, then we can expect the proportion of dark-coloured Soay sheep to decrease further.     

GABAB receptor mRNA in the raphe nuclei: co-expression with serotonin transporter and glutamic acid decarboxylase

We have used double-label in situ hybridization techniques to examine the cellular localization of GABAB receptor mRNA in relation to serotonin transporter mRNA and glutamic acid decarboxylase mRNA in the rat dorsal raphe, median raphe and raphe magnus nuclei. The degree of cellular co-localization of these markers notably varied among the different nuclei. In the dorsal raphe, cell bodies showing GABAB receptor mRNA were very abundant, the 85% being also labelled for serotonin transporter mRNA, and a low proportion (5%) showing glutamic acid decarboxylase mRNA. In the median raphe, the level of co-expression of GABAB receptor mRNA with serotonin transporter mRNA was significantly lower. Some cells were also identified that contained GABAB receptor mRNA in the absence of either one of the other mRNA species studied. Our results support the presence of GABAB receptors in serotonergic as well as GABAergic neurones in the dorsal and median raphe, providing the anatomical basis for the reported dual inhibitory/disinhibitory effect of the GABAB agonist baclofen on serotonergic function.     

Differential Effect of NMDA on Extracellular Serotonin in Rat Midbrain Raphe and Forebrain Sites

Abstract: The contribution of NMDA receptors to regulation of serotonin (5-HT) release was assessed by in vivo microdialysis in freely behaving rats. During infusion of NMDA (30, 100, and 300 µ M ) into the dorsal raphe nucleus (DRN), 5-HT was increased by ∼25, 100, and 280%, respectively. Competitive and noncompetitive NMDA-receptor antagonists blocked this effect on DRN 5-HT. Infusion of NMDA (300 µ M ) into the DRN also produced an 80% increase in extracellular 5-HT in the nucleus accumbens. During infusion of NMDA (100 and 300 µ M ) into the median raphe nucleus (MRN), 5-HT was increased by ∼15 and 80%, respectively. NMDA-receptor antagonists blocked this effect on MRN 5-HT. Infusion of NMDA into the MRN also produced a significant increase in hippocampal 5-HT. In contrast, infusion of NMDA into the nucleus accumbens, frontal cortex, or hippocampus produced small decreases in 5-HT in these forebrain sites. Taken together, these results suggest that NMDA receptors in the midbrain raphe, but not the forebrain, can have an excitatory influence on 5-HT neurons and, thus, produce increased 5-HT release in the forebrain. Furthermore, in comparison with the MRN, DRN 5-HT neurons were more sensitive to the excitatory effect of NMDA.     

Diel thermoregulation of the crawfish Procambarus Clarkii (crustacea, cambaridae)

1. 1. In a diel cycle Procambarus clarkii has two preferred temperatures: 24.0 ± 0.15 SEM °C during the day and 26.7 ± 0.13 SEM °C at night.

2. 2. The preferred temperatures are independent from the weight of the organisms.

3. 3. In the photophase the animals are dispersed, in the scotophase they congregate.

4. 4. The crawfish seem to feed during the thermal interphases.

5. 5. Animals in a constantly dark condition maintain a diel preferendum of temperature.

Comparative aspects of the thermal biology of the short-tailed gerbil, Desmodillus auricularis, and the bushveld gerbil, Tatera leucogaster

1. 1. The response of oxygen consumption (VO₂), thermal conductance (C_d and C_min, body temperature (T_b), and evaporative water loss (EWL) of Tatera leucogaster and Desmodillus auricularis were measured over the range of ambient temperatures (T_a) from 5–35°C.

2. 2. Basal metabolic rate (BMR) of T. leucogaster was 0.841 ± 0.049 ml O₂ g⁻¹ h⁻¹ and lower than predicted, while that of D. auricularis was similar to the expected value (1.220 ± 0.058 ml O₂ g⁻¹ h⁻¹). D. auricularis had a high, narrow thermoneutral zone (TNZ) typical of nocturnal, xerophilic, burrowing rodents.

3. 3. D. auricularis and T. leucogaster regulated T_b over the range T_a = 5–35°C and kept EWL and dry thermal conductance at a minimum below the TNZ. However, the EWL of T. leucogaster increased rapidly above T_a = 30°C.

4. 4. After comparison with data from other species, it was concluded that there is an optimum size for xeric, nocturnal, burrowing rodents.

Thermoregulation in the Red-beillied Blacksnake, Pseudechis porphyriacus (Elapidae)

Cold Pseudechis porphyriacus aid heating by basking, flattening and tilting. When body temperatures are higher, thermoregulation is achieved by shuttling between sun and shade. A warm snake in a cooling environment frequently coils.
The major factors associated with rate of temperature change in the body core were (1) horizontal gradient between body and neck, (2) posture and (3) vertical gradients from body core to body surface.
The role of behavioral, physiological and physical factors in thermoregulation are discussed.     

Wingstroke frequency of foraging and hovering bumblebees in relation to morphology and temperature

Abstract Wingstroke frequency, morphometries and thoracic temperatures of freely foraging bumblebees were examined in the field at ambient temperatures varying from 10 to 29^oC. Frequency was strongly correlated with morphometric parameters, particularly wing length, but was not correlated with either ambient or thoracic temperature. Magnitudes and scaling of frequency of foraging bees were comparable to values obtained for bees hovering in a closed chamber. These data indicate that frequency is primarily determined by morphometric characteristics which determine lift requirements and do not support the hypothesis that frequency is varied in response to environmental conditions as a means of in-flight thermoregulation.     

Locomotor and energetic consequences of behavioral thermoregulation in the sanguivorous leech Hirudo verbana

Medicinal leeches (Hirudo verbana) thermoregulate with respect to their sanguivorous feeding behavior. Immediate postprandial preferences are for warmer than their initial acclimation temperature (T_a, 21 °C, Petersen et al. 2011), while unfed leeches have a lower preferred temperature (T_pref, 12.5 °C). This may reduce energy expenditure and defer starvation if feeding opportunities are limited. Energetic benefits may have an associated cost if low temperatures reduce mobility and the ability to locate further hosts. These costs could be limited if mobility is unimpaired at low temperatures, or if acclimation can restore locomotor performance to the levels at T_a. The transition from T_a to the unfed T_pref significantly reduced speed and propulsive cycle frequency during swimming, and extension and retraction rates during crawling. Aerobic metabolic rate was also reduced from 0.20±0.03 W kg⁻¹ at T_a to 0.10±0.03 W kg⁻¹ at T_pref. The Q₁₀ values of 1.7–2.9 for energetic and swimming parameters indicate a substantial temperature effect, although part of the decline in swimming performance can be attributed to temperature-related changes in water viscosity. 6 weeks at T_a resulted in no detectable acclimation in locomotor performance or aerobic metabolism. The energetic savings associated with a lower T_pref in unfed leeches effectively doubled the estimated time until depletion of energy reserves. Given that some mobility is still retained at T_pref, and that acclimation is in itself costly, the energetic benefits of selecting cooler temperatures between feedings may outweigh the costs associated with reduced locomotor performance.     

Temperature preference in two populations of juvenile coho salmon,oncorhynchus kisutch

Synopsis Two groups of coho salmon,Oncorhynchus kisutch, were raised under identical regimes to test the hypothesis that the group from a stream with lower and less variable temperatures would have a lower and less variable preferred temperature than would the group from a stream with warmer and more variable temperatures. The preferred (modal) temperatures in an electronic shuttlebox of coho salmon young from a relatively cool, groundwater-fed stream were slightly lower and less variable than those of young from a warmer and more heterothermal stream (mean = 9.6° C, range: 6–16° C vs. mean = 11.6° C, range: 7–21° C). However, there was a great deal of variation within and among individual fish. While some genetic variation in thermal preference may exist, the species seems best characterized as tolerant of relatively large temperature fluctuations.