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1.
Low doses of fenvalerate (a Type II pyrethroid) were applied to the beetle Tenebrio molitor at pupation, to ascertain its effects on the developing olfactory system. Doses of fenvalerate that prevent the formation of glomeruli in the primary olfactory neuropil (antennal lobes) also inhibit olfactory orientation behavior for different odors, despite the fact that sensory neurons developed responses to these odors. Even when lower amounts of fenvalerate that allowed glomeruli to develop were applied to pupae, the olfactory behavior was affected. Therefore, the formation of glomerular structures within the antennal lobe is not sufficient to establish olfactory behavior. A possible reason for this developmental effect of fenvalerate is a change in the odotopic arrangement of sensory axons within the glomeruli.  相似文献   

2.
Alterations in brain activity patterns were assessed in response to swim stress by immunocytochemical detection of Fos-like immunoreactivity (Fos-LI) and high-resolution autoradiographic imaging of 14C-2-deoxyglucose (2-DG) uptake. The stress paradigm investigated was a classic behavioral screen for antidepressant drug activity, the forced swim test. One of the most pronounced effects produced by swim stress was an increase in 2-DG uptake and induction of Fos-LI in a restricted region of the lateral septal nucleus. Specific "limbic" cortical regions, including the medial prefrontal, ventrolateral orbital, and cingulate cortices, also exhibited both increased 2-DG uptake and expression of Fos-LI in response to swim stress. In the hypothalamic paraventricular nucleus of swim-stressed rats, Fos-LI was induced but no change in 2-DG uptake was apparent. Since the specific swim stress protocol used is a behavioral screen for antidepressant drugs, the effects of imipramine on stress-induced alterations in 2-DG uptake and induction of Fos-LI were examined. The stress-induced increase in 2-DG uptake in the lateral septum was blocked by treatment with imipramine, but treatment with imipramine had no effect on induction of Fos-LI in the same region. Neither 2-DG uptake nor Fos-LI expression was altered by imipramine treatment in the cortical regions influenced by swim stress. Administration of imipramine alone under basal conditions produced a robust induction of Fos-LI in the central nucleus of the amygdala and in the dorsal lateral subdivision of the bed nucleus of the stria terminalis. No effect of imipramine treatment on 2-DG uptake was apparent in these latter regions. The results provide insights into topographic patterns of brain activity associated with swim stress and neuroanatomically selective actions of imipramine. The different and complementary information obtained by assessment of Fos-LI and 2-DG uptake illustrates the utility of applying both functional mapping approaches to examine neuroanatomical correlates of behavioral states and drug treatment.  相似文献   

3.
Odors evoke synchronized oscillations and slow temporal patterns in antennal lobe neurons and fast oscillations in the mushroom body local field potential (LFP) of the locust. What is the contribution of primary afferents in the generation of these dynamics? We addressed this question in two ways. First, we recorded odor-evoked afferent activity in both isolated antennae and intact preparations. Odor-evoked population activity in the antenna and the antennal nerve consisted of a slow potential deflection, similar for many odors. This deflection contained neither oscillatory nor odor-specific slow temporal patterns, whereas simultaneously recorded mushroom body LFPs exhibited clear 20-30 Hz oscillations. This suggests that the temporal patterning of antennal lobe and mushroom body neurons is generated downstream of the olfactory receptor axons. Second, we electrically stimulated arrays of primary afferents in vivo. A brief shock to the antennal nerve produced compound PSPs in antennal lobe projection neurons, with two peaks at an approximately 50 msec interval. Prolonged afferent stimulation with step, ramp, or slow sine-shaped voltage waveforms evoked sustained 20-30 Hz oscillations in projection neuron membrane potential and in the mushroom body LFP. Projection neuron and mushroom body oscillations were phase-locked and reliable across trials. Synchronization of projection neurons was seen directly in paired intracellular recordings. Pressure injection of picrotoxin into the antennal lobe eliminated the oscillations evoked by electrical stimulation. Different projection neurons could express different temporal patterns in response to the same electrical stimulus, as seen for odor-evoked responses. Conversely, individual projection neurons could express different temporal patterns of activity in response to step stimulation of different spatial arrays of olfactory afferents. These patterns were reliable and remained distinct across different stimulus intensities. We conclude that oscillatory synchronization of olfactory neurons originates in the antennal lobe and that slow temporal patterns in projection neurons can arise in the absence of temporal patterning of the afferent input.  相似文献   

4.
Adult worker honey bees alter their behaviour with age but retain a strong reliance on sensory information from the antennae. The antennae house a diverse array of receptors, including mechanoreceptors, hygroreceptors, olfactory receptors, and contact chemoreceptors, which relay information to the brain. Antennal sensory neurons that project to the antennal lobes of the brain converge onto second-order interneurones to form discrete spheres of neuropil, called glomeruli. The spatial organisation of glomeruli in the antennal lobes of the honey bee is constant, but the central distribution of information from receptors tuned to different sensory modalities is unknown. Here we show that the glomerular neuropil of the antennal lobes undergoes constant modification during the lifetime of the adult worker bee. Changes in morphology are site specific and highly predictable. The total volume of the glomerular neuropil of the antennal lobe increased significantly during the first 4 days of adult life. Each of the five readily identifiable glomeruli examined in this study exhibited a unique pattern of growth. The growth of two of the five glomeruli changed dramatically with the shift to foraging duties. Furthermore, significant differences were identified between the antennal lobes of bees performing nectar- and pollen-foraging tasks. The highly compartmentalized nature of the antennal lobes, the ease with which specific glomeruli can be identified, and the predictability of changes to the antennal lobe neuropil make this an ideal system for examining the mechanisms and behavioural consequences of structural plasticity in primary sensory centres of the brain.  相似文献   

5.
The genetically dystonic (dtSZ) hamster, an animal model of idiopathic paroxysmal dystonia, displays attacks of generalized twisting movements and abnormal postures of limbs and trunk either spontaneously or in response to mild stress. This experimental model may be helpful to give insights into the pathophysiology of idiopathic dystonia in man. In the present study, the regional uptake of [3H]-2-deoxyglucose (2-DG) was examined in brains (75 brain regions) of dtSZ hamsters during the expression of severe dystonia. 2-DG autoradiography revealed significant changes of 2-DG uptake in discrete brain regions of dtSZ hamsters compared with age-matched, nondystonic control hamsters. In dystonic hamsters, a dramatic increase of 2-DG uptake was observed in the red nucleus (159% over control). Furthermore, enhanced 2-DG uptake was found in the ventromedial, ventrolateral, and anteroventral nuclei of the thalamus (19-42%) and in the medial vestibular nucleus (23%). A significant decrease in 2-DG uptake in deep cerebellar nuclei (-30%) may be the result of decreased synaptic activity of GABAergic neurons within these structures resulting in enhanced excitatory output to red nucleus, thalamic, and vestibular nuclei. In dtSZ hamsters, the 2-DG uptake was not significantly altered overall within the basal ganglia. Significant increases of 14% were, however, found in discrete parts of the caudate putamen in which recent studies revealed changes of dopamine receptors. Altered neural activity within the basal ganglia may therefore contribute to increased 2-DG uptake in the ventral thalamic nuclei as well as to decreased 2-DG uptake (-13%) found in the reticular thalamic nucleus. Although the present data are in line with the concept that abnormal thalamocortical activity seems to be critically involved in the dystonic syndrome, altered activities in other motor areas than output structures of the basal ganglia, such as in the red nucleus, may contribute to clinical manifestation of dystonia in mutant hamsters.  相似文献   

6.
Regional brain uptake of 2-deoxydextro-[–1–4C]glucose (2-DG) was measured in 30 Swiss-Webster mice following training in a discriminated Y-maze avoidance task. In comparison with 30 yoked-control Ss that could not escape the footshock, trained Ss had decreased uptake of 2-DG in the hippocampus and increased uptake in the striatum. There was no difference in 2-DG uptake between experimental and control Ss in the cortex overlying the striatum. Additional control studies showed that 2-DG uptake into the brain was not influenced by ether anesthetization or the route of 2-DG administration (iv or ip). Results indicate that the metabolic activity of regional brain areas following training may reflect the involvement of these structures in learning and memory processes. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

7.
The aim of the present study was to determine whether U-50,488H and U-62,066E, kappa-opioid receptor agonists cause a neuroprotective action against hypoxia/hypoglycemia-induced reduction in 2-deoxyglucose (2-DG) uptake of hippocampal slices from U-50,488H-tolerant rats. Both U-50,488H and U-62,066E exhibited an attenuating effect on hypoxia/hypoglycemia-induced reduction in 2-DG uptake of hippocampal slices. Hypoxia/hypoglycemia-induced deficit of 2-DG uptake was prevented by cotreatment with naloxone, an opioid receptor antagonist, but potentiated by cotreatment with morphine, a mu-opioid receptor agonist. Chronic administration of U-50,488H resulted in the development of tolerance to the analgesic effect as well as the neuroprotective effect whereas this treatment affected neither basal- nor hypoxia/hypoglycemia-induced decreases in 2-DG uptake. Chronic administration of U-50,488H did not modify naloxone-induced attenuation of 2-DG uptake deficit but slightly potentiated the morphine-induced exacerbation. These findings suggest that the tolerance to kappa-opioid receptors does not affect the mu-opioid receptor-mediated neuroprotective or neurotoxic action.  相似文献   

8.
9.
Unweighting of the rat soleus by tail-cast suspension results in increased insulin action on stimulation of glucose transport, which can be explained, at least in part, by increased insulin binding and enhanced glucose transporter protein levels. Glucose transport is also activated by an insulin-independent mechanism stimulated by in vitro muscle contractions or hypoxia. Therefore, the purpose of this study was to determine if soleus unweighting leads to an enhanced response of the insulin-independent pathway for stimulation of glucose transport. The hindlimbs of juvenile male Wistar rats were suspended by a tail-cast system for 3 or 6 days. Glucose transport activity in isolated soleus strips (approximately 18 mg) was then assessed by using 2-deoxy-[1,2-3H]glucose (2-DG) uptake. Insulin (2 mU/ml) had a progressively enhanced effect on 2-DG uptake after 3 and 6 days of unweighting (+44 and +72% vs. control, respectively; both P < 0.001). At these same times, there was no difference between groups for activation of 2-DG uptake by maximally effective treatments with contractions (10 tetanuses), hypoxia (60 min), or caffeine (5 mM). These results indicate that the enhanced capacity for stimulation of glucose transport after soleus unweighting is restricted to the insulin pathway, with no apparent enhancement of the insulin-independent pathway.  相似文献   

10.
The central projections of the cold receptor axons were examined by filling two types of cold receptive sensilla with cobalt lysine--a cold and hygroreceptive (C/H) sensillum and a cold receptive and olfactory (C/O) sensillum--on the antennae of the cockroach, Periplaneta americana L. When the dye filled a single C/H sensillum, four axons were stained. Three of these axons terminate in the ipsilateral antennal lobe, while the other branches in the ipsilateral dorsal lobe. One of the branches passed through the tritocerebrum to terminate in the suboesophageal ganglion, while the other branches end in the lobe. When a single C/O sensillum is dye filled, all axons of the four receptor neurons terminate exclusively in the ipsilateral antennal lobe. One axon from the C/H sensillum and one axon from the C/O sensillum terminate in a particular glomerulus in the ventroposterior region of the antennal lobe. Each of these axons also has a tuft in separate glomeruli situated just dorsal to the glomerulus in which both axons terminate. This set of three glomeruli have indistinct boundaries and appear to form a complex of glomeruli similar to the macroglomerular complex of male moths. Assuming modality-specific convergence of antennal afferents, these axons appear to belong to the cold receptor neurons, and the set of glomeruli appear to function in cold reception. Two other neurons stained from C/H sensilla always terminate in the glom-eruli distinct from the set of glomeruli mentioned earlier. These neurons are assigned to the pair of hygroreceptor neurons, and their glomeruli are thought to function in hygroreception.  相似文献   

11.
The primary olfactory neuropil, the antennal lobe (AL) in insects, is organized in glomeruli. Glomerular activity patterns are believed to represent the across-fibre pattern of the olfactory code. These patterns depend on an organized innervation from the afferent receptor cells, and interconnections of local interneurons. It is unclear how the complex organization of the AL is achieved ontogenetically. In this study, we measured the functional activity patterns elicited by stimulation with odours in the right and the left AL of the same honeybee (Apis mellifera) using optical imaging of the calcium-sensitive dye calcium green. We show here that these patterns are bilaterally symmetrical (n=25 bees). This symmetry holds true for all odours tested, irrespective of their role as pheromones or as environmental odours, or whether they were pure substances or complex blends (n=13 odours). Therefore, we exclude that activity dependent mechanisms local to one AL determine the functional glomerular activity. This identity is genetically predetermined. Alternatively, if activity dependent processes are involved, bilateral connections would have to shape symmetry, or, temporal constraints could lead to identical patterns on both sides due to their common history of odour exposure.  相似文献   

12.
The antennal lobes (ALs), the primary olfactory centers, of the moth Manduca sexta are sexually dimorphic. Only ALs of males possess the macroglomerular complex (MGC), the site of primary processing of information about the female's sex pheromone. To understand the development of identified, odor-specific olfactory glomeruli, we investigated the cellular events involved in the morphogenesis of the MGC by means of various fluorescence staining techniques and laser-scanning confocal microscopy. The MGC lies near the entrance of the antennal nerve into the AL of the adult male and comprises three glomeruli, the globular cumulus and two toroidal structures. The MGC forms during early stages of metamorphic adult development through a stereotyped sequence of coordinated changes in MGC-specific receptor axons, glial cells, and early-ingrowing projection neurons of the medial group of AL neurons. The MGC divisions are the earliest glomeruli to form in the male AL, and their basic organization is established within about 3 days after ingrowth of the first sensory axons. Despite their special anatomical features, the MGC glomeruli develop in a manner similar to that of the ordinary glomeruli. Comparison of the ALs of males and females reveals that two relatively large and early-developing glomeruli that are situated dorsolaterally in the female AL appear to be female-specific. Development of the sexually dimorphic glomeruli diverges immediately after the ingrowth of the first olfactory receptor axons, resulting in the formation of these large glomeruli in females and the MGC in males.  相似文献   

13.
The atypical glomeruli constitute a particular subset of olfactory glomeruli in the rat olfactory bulb which is mainly characterized by a strong centrifugal cholinergic innervation. In the present study, the topographical organization of the mucoso-bulbar projection of these glomeruli was analysed using small injections of WGA-HRP into the anterior nasal cavity of adult rats. The atypical olfactory glomeruli were visualized on adjacent bulbar sections using acetylcholinesterase histochemistry. A mean of 29 atypical glomeruli per bulb was observed in several areas of the posterior half of the olfactory bulb. Following the rostro-caudal axis of the olfactory bulb, the first atypical glomeruli were located in lateral positions, then in dorsal and ventral ones. The most posterior atypical glomeruli were located in the bulbar medial side. Concerning the projections from the periphery to the atypical glomeruli, various WGA-HRP patterns of labelling were observed. When the surface area of injection sites in the anterior part of the olfactory sheet was between 30 and 40 mm2, half of the atypical population was labelled with the atypical glomeruli being heavily labelled. All sites of distribution previously described were represented. When the surface area of injection sites was inferior to 20 mm2, only some positions distributed along the bulbar antero-posterior axis were represented. These atypical glomeruli were generally partially labelled. Taken together, these results suggest that, although atypical glomeruli are restricted in the posterior olfactory bulb, they receive peripheral projections diffusely organized along the antero-posterior axis of the olfactory mucosa. This profile was compared with that of other classical olfactory glomeruli.  相似文献   

14.
Odor information is first represented in the brain by patterns of input activity across the glomeruli of the olfactory bulb (OB). To examine how odorants are represented at this stage of olfactory processing, we labeled anterogradely the axons of olfactory receptor neurons with the voltage-sensitive dye Di8-ANEPPQ in zebrafish. The activity induced by diverse natural odorants in afferent axons and across the array of glomeruli was then recorded optically. The results show that certain subregions of the OB are preferentially activated by defined chemical odorant classes. Within these subregions, "ordinary" odorants (amino acids, bile acids, and nucleotides) induce overlapping activity patterns involving multiple glomeruli, indicating that they are represented by combinatorial activity patterns. In contrast, two putative pheromone components (prostaglandin F2alpha and 17alpha, 20beta-dihydroxy-4-pregnene-3-one-20-sulfate) each induce a single focus of activity, at least one of which comes from a single, highly specific and sensitive glomerulus. These results indicate that the OB is organized into functional subregions processing classes of odorants. Furthermore, they suggest that individual odorants can be represented by "combinatorial" or "noncombinatorial" (focal) activity patterns and that the latter may serve to process odorants triggering distinct responses such as that of pheromones.  相似文献   

15.
Bactericidal effect of the Nd:YAG laser in in vitro root canals   总被引:1,自引:0,他引:1  
The spatio-temporal patterns of neural activity evoked by electrical stimuli to the antennal nerve (AN) in male cockroach antennal lobes (ALs) in vivo were analyzed by optical imaging using a voltage-sensitive dye. The response pattern was initially a depolarization on the AN and subsequently a depolarization followed by a hyperpolarization on the whole area of macroglomerulus (MG) and a part of ordinary glomerulus (OG). It was suggested by the pharmacological results that the depolarizing responses on the AL consist of both a presynaptic response, representing synchronous compound action potentials from the AN, and a postsynaptic response, representing synchronous compound excitatory postsynaptic potentials and action potentials from neurites of AL neurons, and that the inhibitory responses of GABAergic local interneurons in the AN are different in time course from that in the AL.  相似文献   

16.
OBJECTIVE: Based on the hypothesis that blood flow in the inflamed joint is inadequate to maintain aerobic glycolysis, we sought to estimate the correlation between blood flow, glucose metabolism, and cellular proliferation rate in the arthritic joint. METHODS: Experiments were performed on rats with antigen induced arthritis (AIA). Regional blood flows (RBF) were measured with the microsphere technique, glucose metabolism by determination of [14C]2-deoxy-D-glucose (2-DG) uptake, and the proliferative response as the incorporation of [3H]-thymidine. RESULTS: In periarticular soft tissue of the arthritic knee the only significant change in the weight related RBF was an approximate 70% rise on Day 14 after arthritis onset. The RBF was lowest on Day 3 and the time course for the changes was inversely related to intensity of vascular inflammation. Weight related 2-DG uptake was more elevated than the RBF and peaked on Day 3. [3H]-thymidine incorporation in the soft tissue was only markedly enhanced on Day 3. Neither 2-DG nor [3H]-thymidine uptake was affected by treatment with methotrexate or indomethacin. In epiphyseal bone RBF was reduced on the first day of arthritis, but steadily increased thereafter. CONCLUSION: In AIA an intense vascular leakiness negatively affects the synovial blood. There is a marked enhancement of glucose metabolism, but only a minor part of this increase seems to be induced by increased cellular proliferation.  相似文献   

17.
The nitric oxide (NO)-cGMP signaling system is thought to play important roles in the function of the olfactory system in both vertebrates and invertebrates. One way of studying the role of NO in the nervous system is to study the distribution and properties of NO synthase (NOS), as well as the soluble guanylyl cyclases (sGCs), which are the best characterized targets of NO. We study NOS and sGC in the relatively simple and well characterized insect olfactory system of the hawkmoth, Manduca sexta. We have cloned Manduca sexta nitric oxide synthase (MsNOS) and two sGCs (MsGCalpha1 and MsGCbeta1), characterized their basic biochemical properties, and studied their expression in the olfactory system. The sequences of the Manduca genes are highly similar to their mammalian homologs and show similar biochemical properties when expressed in COS-7 cells. In particular, we find that MsGC functions as an obligate heterodimer that is stimulated significantly by NO. We also find that MsNOS has a Ca2+-sensitive NO-producing activity similar to that of mammalian neuronal NOS. Northern and in situ hybridization analyses show that MsNOS and the MsGCs are expressed in a complementary pattern, with MsNOS expressed at high levels in the antennae and the MsGCs expressed at high levels in a subset of antennal lobe neurons. The expression patterns of these genes suggest that the NO-sGC signaling system may play a role in mediating communication between olfactory receptor neurons and projection neurons in the glomeruli of the antennal lobe.  相似文献   

18.
In the female red-sided garter snake (Thamnophis sirtalis parietalis), the loss of receptivity following intromission during mating can be prevented by injection of a local anesthetic (tetracaine) in the cloacal region prior to courtship and mating. Females that were courted and then mated had significantly higher uptake of radio-labeled [1?C]2-fluoro-2-deoxyglucose (2-DG) in the preoptic area (25%) and significantly lower uptake in the ventromedial hypothalamus (-20%) compared with females that were courted but not mated. Tetracaine-treated females had accumulation patterns similar to courted but unmated females and to females exposed only to other females. These results suggest that in the female red-sided garter snake, sensory input from the cloaca during mating alters patterns of metabolism in those brain areas most often associated with female sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
Insulin increased 2-deoxyglucose (2-DG) uptake via the translocation of glucose transporter (GLUT) 4 to the plasma membrane fraction in rat adipocytes. The stimulatory actions of insulin were accompanied by both an increase in the immunoreactive p85 subunit of phosphatidylinositol (PI) 3-kinase in the plasma membrane fractions and PI 3-kinase activation by tyrosine phosphorylation of the p85 subunit. The beta3-adrenoceptor agonist CL316243 (CL) suppressed all the insulin actions in adenosine deaminase (ADA)-treated cells, but was without effect in non-ADA-treated cells. The inhibitory effects of CL on GLUT 4 translocation and PI 3-kinase activation were abolished by the addition of N6-phenylisopropyl adenosine. Cholera toxin treatment, which markedly increased intracellular cAMP levels, suppressed increases in the levels of GLUT 4 and PI 3-kinase in the plasma membrane fractions in response to insulin. In addition, dibutyryl (Bt2) cAMP also impaired the activation of PI 3-kinase by insulin. These results indicated that CL suppressed insulin-stimulated glucose transport under conditions where cAMP levels were markedly increased (approximately 12-fold). The inhibitory actions of PI 3-kinase activation by insulin were exerted even when cAMP, 8-bromo-cAMP, or Bt2 cAMP was added to immunoprecipitates of the p85 subunit of PI 3-kinase, after treating the cells with insulin. These results suggest that CL suppressed insulin-stimulated PI 3-kinase activity via a cAMP-dependent mechanism, at least in part, direct cAMP action in ADA-treated adipocytes, by which PI 3-kinase activation was inhibited, resulting in the decrease in GLUT 4 translocation and subsequent 2-DG uptake in response to insulin.  相似文献   

20.
Spatial patterns of glomerular activity in the vertebrate olfactory bulb and arthropod antennal lobe reflect an important component of first-order olfactory representation and contribute to odorant identification. Higher concentration odor stimuli evoke broader glomerular activation patterns, resulting in greater spatial overlap among different odor representations. However, behavioral studies demonstrate results contrary to what these data might suggest: Honeybees are more, not less, able to discriminate among odorants applied at higher concentrations. Using a computational model of the honeybee antennal lobe, the authors show that changes in synchronization patterns among antennal lobe projection neurons, as observed electrophysiologically, could parsimoniously underlie these observations. The results suggest that stimulus salience, as defined behaviorally, is directly correlated with the degree of synchronization among second-order olfactory neurons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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