Transplantation of nasal olfactory tissue promotes partial recovery in paraplegic adult rats

Recent reports have highlighted the potential therapeutic role of olfactory ensheathing cells for repair of spinal cord injuries. Previously ensheathing cells collected from the olfactory bulbs within the skull were used. In humans a source of these cells for autologous therapy lies in the nasal mucosa where they accompany the axons of the olfactory neurons. The aim of the present study was to test the therapeutic potential of nasal olfactory ensheathing cells for spinal cord repair. Olfactory ensheathing cells cultured from the olfactory lamina propria or pieces of lamina propria from the olfactory mucosa were transplanted into the transected spinal cord. Three to ten weeks later these animals partially recovered movement of their hind limbs and joints which was abolished by a second spinal cord transection. Control rats, receiving collagen matrix, respiratory lamina propria or culture medium, did not recover hind limb movement. Recovery of movement was associated with recovery of spinal reflex circuitry, assessed using the rate-sensitive depression of the H-reflex from an interosseous muscle. Histological analysis of spinal cords grafted with olfactory tissue demonstrated nerve fibres passing through the transection site, serotonin-positive fibres in the spinal cord distal to the transection site, and retrograde labelling of brainstem raphe and gigantocellularis neurons from injections into the distal cord, indicating regeneration of descending pathways. Thus, olfactory lamina propria transplantation promoted partial restoration of function after relatively short recovery periods. This study is particularly significance because it suggests an accessible source of tissue for autologous grafting in human paraplegia.     

Behavioral and neuropsychological foundations of olfactory fear conditioning

Pavlovian fear conditioning procedures have been a fruitful means of exploring the neural substrates of associative learning. There is now substantial evidence suggesting that many aspects of conditioned fear depend critically upon the integrity of the amygdala and the perirhinal cortex. Recent studies in our laboratory examining the contributions of these areas to olfactory and contextual fear conditioning are reviewed; collectively the results of these studies suggest that the amygdala participates critically in the acquisition and expression of fear conditioned to both an olfactory conditioned stimulus (CS) and to the training context, while the perirhinal cortex contributes to olfactory, but not contextual, fear conditioning. Moreover, it appears that perirhinal cortex may play a prominent role in recognition of the CS following conditioning. These results are discussed in light of the extent to which they replicate and extend previous research examining the contributions of these areas to fear conditioned to auditory and visual CSs.     

Experience facilitates vomeronasal and olfactory influence on Fos expression in medial preoptic area during pheromone exposure or mating in male hamsters

Chemosensory stimuli are essential for mating in male hamsters but either main olfactory or vomeronasal input is sufficient in sexually experienced males. Activation in central chemosensory pathways and medial preoptic area, after stimulation with female chemosignals or after mating, was estimated by counting neurons expressing Fos protein in experienced and naive males, with or without vomeronasal organ lesions. Regions counted included main and accessory olfactory bulbs, corticomedial amygdala, bed nucleus stria terminalis and medial preoptic area. Chemosensory stimulation was more effective in activating medial preoptic area in experienced than in naive males. In experienced males with vomeronasal organs removed, main olfactory input was as effective in activating medial preoptic area as was the combination of main and accessory input available to intact animals. As previously reported, the main olfactory input remaining after vomeronasal lesions in naive males was poorly effective in activating medial preoptic area, and these animals had impaired mating behavior. The change in access of chemosensory input to medial preoptic area after experience suggests that an experience-dependent synaptic modulation in this pathway, perhaps in the amygdala, may underlie some changes in mating behavior with experience.     

Effects of dopamine and norepinephrine on neuronal activity of the olfactory tubercle

The effects of iontophoretic administration of norepinephrine (NE) and dopamine (DA) on olfactory tubercle (OT) neurons that respond to lateral hypothalamus (LH) or locus coeruleus (LC) electrical stimulation were studied. NE and DA decreased the frequency of OT neurons which were increased or decreased by the LH stimulation. An increased firing of OT neurons following NE or DA administration was less frequently observed. NE administration decreased the firing of OT neurons that responded to LC stimulation. These results suggest that the LC fibers which reach the OT use NE as a neurotransmitter. DA administration also suppressed the unitary discharge of OT neurons responding to LC stimulation. The increase in frequency of OT neurons observed following LH stimulation cannot be attributed to DA. The possibility that other suspected neural transmitters are involved in this effect is discussed.     

Glial investment of the adult and developing antennal lobe of Drosophila

In recent years the Drosophila olfactory system, with its unparalleled opportunities for genetic dissection of development and functional organization, has been used to study the development of central olfactory neurons and the molecular basis of olfactory coding. The results of these studies have been interpreted in the absence of a detailed understanding of the steps in maturation of glial cells in the antennal lobe. Here we present a high-resolution study of the glia associated with olfactory glomeruli in adult and developing antennal lobes. The study provides a basis for comparison of findings in Drosophila with those in the moth Manduca sexta that indicate a critical role for glia in antennal lobe development. Using flies expressing GFP under a Nervana2 driver to visualize glia for confocal microscopy, and probing at higher resolution with the electron microscope, we find that glial development in Drosophila differs markedly from that in moths: glial cell bodies remain in a rind around the glomerular neuropil; glial processes ensheathe axon bundles in the nerve layer but likely contribute little to axonal sorting; their processes insinuate between glomeruli only very late and then form only a sparse, open network around each glomerulus; and glial processes invade the synaptic neuropil. Taking our results in the context of previous studies, we conclude that glial cells in the developing Drosophila antennal lobe are unlikely to play a strong role in either axonal sorting or glomerulus stabilization and that in the adult, glial processes do not electrically isolate glomeruli from their neighbors.     

经鼻滴入海人藻酸引起C57BL/6小鼠嗅球和海马区神经元的退行性病变

目的 应用海人藻酸(KA)在C57BL／6小鼠建立神经退行性病变动物模型并观察其对嗅球神经元的影响。方法 经鼻滴人KA应用尼氏和嗜银染色观察海马及嗅球的病理变化，免疫组化检测Cyclooxygenase2(COX-2)的表达。结果 经鼻滴入KA成功地在C57BL／6小鼠建立了神经退行性病变动物模型，KA通过嗅神经引起双侧嗅球和海马损伤，其病变程度与小鼠体重和滴入KA剂量有关，同时KA引起了脑内明显的胶质细胞增生和炎症因子COX-2在嗅球部的表达。结论 经鼻滴入KA能够引起嗅球和海马的损伤。     

改良鼻窦CT嗅区评分对慢性鼻-鼻窦炎鼻息肉嗅觉评估及预后判断的价值

目的　探讨改良鼻窦CT嗅区评分对慢性鼻-鼻窦炎鼻息肉患者术前嗅觉功能评估及术后嗅觉功能判断的价值。方法　前瞻性分析慢性鼻-鼻窦炎鼻息肉患者54例,排除合并哮喘、变应性鼻炎和伴有可能影响嗅觉功能的系统性因素。所有患者均接受功能性鼻内镜手术和规范的药物治疗,并行术后随访。根据鼻窦CT冠状位嗅裂区堵塞程度评为0、1、2分,分别对嗅裂前区（anterior olfactory cleft score,AOCS）（中鼻甲对应嗅裂区）和嗅裂后区（posterior olfactory cleft score,POCS）（上鼻甲对应嗅裂区）进行评分。术前所有患者均进行T&T嗅觉检测、嗅觉VAS评分和改良鼻窦CT嗅区评分和鼻窦CT Lund-Mackay评分,术后行T&T嗅觉检测、嗅觉VAS评分。分别将患者术前及术后6个月嗅觉阈值、嗅觉VAS评分与改良鼻窦CT嗅区评分和Lund-Mackay评分进行线性回归分析。结果　本研究纳入慢性鼻-鼻窦炎鼻息肉患者54例,其中男性36例,女性18例,平均年龄47.9岁（24～67岁）,其中30例患者随访达到6个月。线性回归分析结果显示,患者T&T嗅觉阈值与嗅觉VAS评分有显著相关性（Pearson相关系数r =0.70,P <0.01）。手 术前改良鼻窦CT嗅区评分AOCS和POCS均与嗅觉阈值评分、嗅觉VAS评分显著正相关（P <0.001）,Lund-Mackay评分与嗅觉阈值也有弱相关性（R 2=0.262,P =0.005）。手术前鼻窦CT嗅区评分AOCS、POCS与术后6个月的嗅觉阈值亦有相关性（R 2=0.211、0.181,P =0.014、0.024）,且术前AOCS与术后6个月嗅觉阈值正相关性更强。术前Lund-Mackay评分与术后6个月嗅觉阈值无相关性（R 2=0.073,P =0.165）。结论　改良鼻窦CT嗅区评分可作为慢性鼻-鼻窦炎鼻息肉患者术前嗅觉功能和功能性鼻内镜手术后嗅觉功能预后的客观评价指标。中鼻甲对应的嗅裂区的病变程度对嗅觉功能评价作用更重要。     

Olfactory sensitivity for aliphatic ketones in squirrel monkeys and pigtail macaques

Using a conditioning paradigm, the olfactory sensitivity of three squirrel monkeys and three pigtail macaques for homologous series of aliphatic 2-ketones (2-butanone to 2-nonanone), symmetrical ketones (3-pentanone to 6-undecanone), and C7-ketones (2-heptanone to 4-heptanone) was assessed. In the majority of cases, the animals of both species significantly discriminated concentrations below 1 ppm from the odorless solvent, and with 2-nonanone and 5-nonanone the monkeys even demonstrated thresholds below 1 ppb. The results showed both primate species have a well-developed olfactory sensitivity for aliphatic ketones, and pigtail macaques generally perform better than squirrel monkeys in detecting members of this class of odorants. Further, in both species tested, we found a significant negative correlation between perceptibility in terms of olfactory detection thresholds and carbon-chain length of both the 2-ketones and the symmetrical ketones, but not between detection thresholds and position of the functional group with the C7-ketones. These findings lend further support to the growing body of evidence suggesting that between-species comparisons of the number of functional olfactory receptor genes or of neuroanatomical features are poor predictors of olfactory performance.     

Changes in olfactory inputs modify the energy balance response to short days in male gray mouse lemurs

The role of olfaction/olfactory cues on photoperiodic responses was assessed in Malagasy primate, the gray mouse lemur. When exposed to short photoperiod (SP), this primate demonstrates rapid changes in energy balance as adaptive anticipatory response for winter survival. To follow early changes induced by SP exposure, body mass, food intake, resting metabolism (RMR) and free thyroxin levels in plasma (T4) were measured in males abruptly transferred to SP: six intact males (controls), eight males that underwent bilateral olfactory removal (BOX) and eight males exposed to male urinary cues (U-exposed). To assess the effect of SP exposure, two other groups were maintained for 6 weeks under LP: six controls and six BOX males. Whereas all studied parameters remained constant in controls and BOX males maintained under LP, exposure to SP led to different responses according to groups. In controls, SP exposure led to a regular increase in body mass and after 4 weeks under SP, plasma T4 levels, food consumption and RMR significantly decreased. Even if BOX males demonstrated hyperphagic patterns regardless of the photoperiod, an increase in body mass was also induced by SP exposure but without changes in RMR or food intake that were body mass-dependent. In U-exposed males, body mass gain was significantly reduced while food intake and RMR remained high. In both BOX and U-exposed males, SP exposure led to a transient but high increase in T4 levels compared to controls. These results suggest that olfaction/olfactory cues may delay the SP-mediated changes in energy balance.     

Odor discrimination of "IP 3-" and “cAMP-increasing” odorants in the turtle olfactory bulb

The ability of the turtle olfactory system to discriminate between various odorants that increase levels of adenosine 3′,5′-cyclic monophosphate (cAMP) and inositol trisphosphate (IP ₃) in the olfactory bulb was examined by the cross-adaptation technique and analyzed by multidimensional scaling. The mean values of the degree of discrimination among the IP ₃-increasing odorants were higher than those among the cAMP-increasing odorants, and were similar to those between cAMP- and IP ₃-increasing odorants, suggesting that the features of the receptors of cAMP-increasing odorants are different from those which respond to IP ₃-increasing odorants. Analysis by multidimensional scaling suggested that differences in second messenger pathways are not related to detecting odor quality in the turtle olfactory system. Received: 21 July 1995/Received after revision: 20 October 1995/Accepted: 6 November 1995