Raised corticosterone in the rat after exposure to the elevated plus-maze

Rats given one or two 5-min trials in the elevated plus-maze had plasma corticosterone concentrations significantly higher than the home cage control group and there was no sign of habituation in the group given two trials. In rats given two plus-maze trials the corticosterone responses were significantly higher in the group given 10-min rather than 5-min trials. A previous experience of cat odour (1 week earlier) has no effect on the plasma corticosterone response, but did have an anxiogenic effect that could be detected by a decrease in the percentage of time spent on the open arms of the plus-maze. The results are discussed with reference to the nature of anxiety generated by trials 1 and 2 and by the trial duration in the plus-maze, and with respect to dissociation between behavioural and endocrinological measures.     

基于Heracles NEO超快速气相电子鼻麸炒白术炮制全过程气味变化识别研究

目的 建立麸炒白术Atractylodis Macrocephalae Rhizoma炮制全过程的定性判别模型,筛选出可以表征麸炒白术不同炮制程度的气味成分。方法 制备麸炒白术饮片,不同时间点取样进行分析。采用Heracles NEO超快速气相电子鼻采集气味图谱,与Arochembase数据库对比得到气味成分信息,结合峰面积分析气味成分的变化规律并进行化学计量学分析。结果 通过判别因子分析（discriminant factor analysis,DFA）、正交偏最小二乘-判别分析（orthogonal partial least squaresdiscriminant analysis,OPLS-DA）、层次聚类分析（hierarchical cluster analysis,HCA）等将麸炒白术炮制全过程样品成功分为4类：生品、炮制不及、炮制成品和炮制太过。在炮制过程中,3-甲基十五烷、十二烷基丙酸酯、正辛基环己烷、1,3-二硝基苯、8-甲基十五烷5个气味成分的峰面积占比较高,其中1,3-二硝基苯在炮制全过程中峰面积呈降低趋势;3-甲基十五烷从炮制不及到炮制成品的过程中峰面积呈增加...     

Insecticide and fungicide effect on thermal and olfactory behavior of bees and their disappearance in bees’ tissues

Plant protection products may affect the behavior of organisms which are not a target of control. The effect of Karate Zeon 050 CS (λ-Cyhalothrin -based insecticide; λ-CBI) and Amistar 250 SC (Azoxystrobin-based fungicide; ABF) was determined on Apis mellifera worker attraction towards their own colony odour, along with temperature preferences. Bees exposed to pesticides prefer the environment with the odour of their nest less often than the control group, and that insecticide-treated bees chose warmer environments than the control insects. The observed differences in the bees, especially with attraction towards their own colony, were dependent on the time of day. Chromatographic analyses indicated that λ-Cyhalothrin elimination was half that of Azoxystrobin in bee organisms, and both agents retarded each other’s clearance. Mathematical modeling estimated that despite a relatively high disappearance rate, both compounds might have been bio-accumulated at relatively high level.     

Repellency of tsetse-refractory waterbuck (Kobus defassa) body odour to Glossina pallidipes (Diptera: Glossinidae): Assessment of relative contribution of different classes and individual constituents

Our earlier studies on the comparative behavioural responses of caged savanna tsetse (Glossina morsitans morsitans and Glossina pallidipes) on a preferred host (ox) and a non-host (waterbuck) suggested the presence of allomonal constituents on the latter. Follow up comparison of the compositions of odours of waterbuck with those of ox and buffalo led to the identification of a series of compounds (15) specific to waterbuck, including straight chain carboxylic acid (C₅–C₁₀), phenols (guaiacol and carvacrol), 2-alkanone homologues (C₈–C₁₂), geranylacetone and δ-octalactone. Behavioural studies in a windtunnel in the laboratory suggested that G. m. morsitans was repelled by a synthetic blend of waterbuck-specific constituents. In the present study, the effects of different blends of these compounds on catches of mixed sexes of G. pallidipes in attractant-baited NG2G traps were evaluated in the field. Each multicomponent class of constituents (acids, ketones and phenols) was found to reduce fly catches, but a 14-component blend of all these compounds was more effective (reduced catches by 79–85%), indicating that each of these classes of compounds contributes incrementally to the repellency of the waterbuck odour. However, subtractive assays showed some redundancy within each class of compounds, with some even demonstrating attractive properties. Addition of (RS)-δ-octalactone to the 14-component significantly increased the repellency of the resulting blend. A 5-component blend of compounds selected on the basis of their relative performance in subtractive assays (δ-octalactone, guaiacol, geranylacetone, hexanoic and pentanoic acid) showed substantial reduction in fly catches (84%) relative to the baited control. In separate sets of experiments involving an ox tethered in the middle of an incomplete ring of electric screens in the presence or absence of 15-component or 5-component blends, comparable levels in the reduction of fed flies (94 and 96%, respectively) were obtained with the two blends. The chemo-ecological significance and practical implication of these results are highlighted.     

A multimodal MR-compatible olfactometer with real-time controlling capability

Abstract

Design of an MR-compatible and computer-controlled odour stimuli system is essential in the studies of human olfactory function. Olfactometers are used to deliver odours to the subjects in an objective manner. We present a portable, computer-controlled eight channels olfactometer able to stimulate olfaction by employing liquid odorant stimuli. We used a high-pressure pump to generate medical grade airflow. After passing through solenoid valve-controlled odour reservoirs, odorant stimulus is conveyed to the nasal mask. The odour delivery delay of the device was measured using photo-ionisation detectors. To assess the application of the designed olfactometer, an fMRI experiment was done with 9 healthy subjects. Two odour stimuli (Vanillin and Rose) were presented to each subject in an alternating block design task of odour and non-odour conditions. The response time of each subject was gathered using the response box. Group analysis revealed a significant BOLD signal change in some regions of olfactory and trigeminal networks including the orbitofrontal cortex, insula, inferior frontal gyrus, hippocampus, cingulate gyrus and piriform cortex. The odour delivery delay measured by photo-ionisation detector was 190?ms, and the subjects’ response showed 205?ms for the Vanillin and 243?ms for the Rose odour stimuli. Our portable MR-compatible olfactometer as a stimulation device is capable of creating adequate stimulation suitable for olfactory fMRI experiments.     

Olfactory receptor cells on the cockroach antennae: responses to the direction and rate of change in food odour concentration

In insects, information about food odour is encoded by olfactory receptor cells with characteristic response spectra, located in several types of cuticular sensilla. Within short, hair-like sensilla on the cockroach's antenna, antagonistic pairs of olfactory receptor cells shape information inflow to the CNS by providing excitatory responses for both increases and decreases in food odour concentration. The segregation of food odour information into parallel ON and OFF responses suggests that temporal concentration changes become enhanced in the sensory output. When food odour concentration changes slowly and continuously up and down with smooth transition from one direction to another, the ON and OFF olfactory cells not only signal a succession of odour concentrations but also the rate with which odour concentration happens to be changing. Access to the values of such cues is of great use to an insect orientating to an odour source. With them they may extract concentration gradients from odour plumes.     

Developmental changes in responsivity to threat are stimulus-specific in rats

During early ontogeny, stimuli that pose a threat to an animal change. Unrelated adult male rats may kill young rats, but infanticide ends around weaning. Predation, on the other hand, may increase during early ontogeny when rats begin to extend their activity range. We investigated the developmental course of two defensive responses, immobility and analgesia, in young rats exposed to an adult male rat or to predator cues. Preweaning 14-day-old rats became immobile and analgesic when exposed to the male and showed immobility but not analgesia when exposed to cat odor. On Day 26, around weaning, the presence of the male rat no longer induced immobility and analgesia whereas cat odor produced higher levels of immobility and analgesia compared to control and male-exposed animals. This developmental change in responsivity may reflect the differences in the risk of being harmed by a male or a cat during different periods of ontogeny.     

The coding of odour-intensity in the honeybee antennal lobe: local computation optimizes odour representation

We investigated strategies involved in odour intensity coding by the primary olfactory centre of insects, the antennal lobe (AL), the structural and functional analogue of the olfactory bulb. Using calcium imaging in the honeybee, we simultaneously measured the projection neuron output responses and a compound signal dominated by receptor neuron input in identified olfactory glomeruli to odours spanning seven log units of concentration. A comparison of the two processing levels indicates that the intercellular computation within the AL modulates and contrast-enhances the primary olfactory signals. As a result the AL network optimizes the olfactory code: odour representation is improved at lower concentrations, the relative activity of olfactory glomeruli allows encoding odour quality over up to four log-unit concentrations, and odour-intensity is reliably represented in the overall excitation across AL.     

Predator and restraint stress during gestation facilitates pilocarpine-induced seizures in prepubertal rats

Stress during gestation can result in early and long-term developmental aberrations. This study aimed to assess the impact of prenatal restraint or predator stress on pilocarpine-induced epileptic behavior. Pregnant rats were exposed to stressors on gestational days 15, 16, and 17. Restraint stress consisted of daily restraint of the dam. During predator stress, caged rats were exposed to a cat in a cage. On postnatal day 25, male pups were injected with pilocarpine and the behavior of each rat was observed. Prenatal stress led to low birth weight and increased blood corticosterone levels. Both stressors significantly potentiated pilocarpine-induced seizures. Predator-stressed pups exhibited significantly severe tonic-clonic seizures compared with restraint-stressed animals. These data emphasize the impact of prenatal stress on fetal growth, and neural and endocrine function. The results also suggest that psychosocial stressors have a greater impact on neural and endocrine function than physical stressors do.