鲜味

1甜味和鲜味:孰优孰劣味觉和嗅觉是鉴别食物的两种外周感觉机制。味觉系统通过味蕾感知食物的营养价值,味蕾则被定义为舌头上的味觉感知细胞簇(图1)。正如在本系列专栏第一部分中介绍的那样(The GoodTaste Of Pigs(1):Let It Be Sweet),     

青海高原牦牛肩胛上、下神经和腋神经解剖

本文报道了生活在高寒低氧环境下的青海高原牦牛的肩胛上、下神经和腋神经的起源、位置、行程、分支和分布情况。其主要特征是肩胛上神经、肩胛下神经纤维都来自第６、第７颈神经的腹侧支、其神经的分支支配与牛、水牛、马的基本相同。腋神经纤维来自第７、第８颈神经和第１胸神经,其分支支配三角肌、小圆肌、冈下肌、臂头肌锁臂部以及前臂的筋膜和皮肤     

青海高原牦牛肩钾上,下神经和腋神经解剖

本文报道了生活在高寒低氧环境下的青海高原牦牛的肩钾上,下神经和腋神经的起源,位置,行程,分支和分布情况,其主要特征是肩钾上神经、肩胛下神经纤维都来自第６、第７项神经的腹侧支,其神经的分支支配与牛、水牛、马的基本相同。腋神经纤维来自第７、第８颈神经和第１胸神经,其分支支配三角肌,小圆肌,冈下肌,臂头肌锁臂部以及前臂的筋膜和皮肤。     

兔减压神经的纤维成分—HRP法

艇ＨＲＰ法对兔减压神经进行了研究，标记的传入神经元绝大多数位于迷走神经结状节尾侧半部偏一侧，少数见于颈静脉神经节，其中枢突标记终末见于延髓闩以上的孤束核内侧部，腹侧部以及迷背核内。在颈前节也出现标记细胞，表明减压神经中也含有起源于 前节的交感节后纤维成分。主动脉压力感受器有经减压神经来的感觉神经交感节后神经纤维支配。提示减压神经是含有一般内脏传入和一般内脏传出纤维的混合神经，为研究心血管生理提供了     

饲料诱食剂在饲料工业中的应用及发展

近年来,随着饲料工业和养殖业的迅速发展,饲料诱食剂在饲料工业和畜禽生产中的应用得到了长足的发展。研究饲料诱食剂的发展状况和应用技术,对提高产品质量,推动饲料工业发展和最大程度地提高动物生产水平有着十分现实的意义。１饲料的风味和饲料诱食剂的作用机理饲料的风味是动物通过味觉和嗅觉两部分组成对饲料综合的感觉,味觉是被溶解的物质通过味蕾的味孔,作用于味细胞引起细胞兴奋发放冲动传递给神经中枢引起的感觉。味觉主要有甜、酸、苦、咸４种基本类型,当动物饥饿时,对甜的味觉敏感度增高,而当消化系统发生疾病时,味觉敏感度显著降…     

昆虫味觉受体研究进展

化学感受受体在昆虫的觅食、食物选择、交配和产卵等行为中发挥着重要作用。随着果蝇、按蚊、蜜蜂、赤拟谷盗和家蚕等昆虫基因组测序的完成。各物种中完整化学感受受体（包括嗅觉受体和味觉受体）得以鉴定,并从中鉴定出与气味识别、食物选择密切相关的受体基因,如果蝇的二氧化碳受体基因DmGr21a和DmGr63a,糖受体DmGr5a,以及冈比亚按蚊识别人类气味的AgOrl等。其中,昆虫的味觉受体功能与昆虫食物选择、大量取食直接相关。本文就目前昆虫基因组中味觉受体的鉴定、进化、表达和功能等方面的研究进展进行了综述。对味觉受体功能的研究,将有助于我们认识昆虫味觉编码的分子基础和神经调控网络,也是研究昆虫与植物相互关系的热点。     

孕激素受体在雌性山羊颈前神经节的分布

为研究雌性山羊颈前神经节(SCG)是否具备接受孕激素作用的条件,从而推测孕激素是否参与靶器官内分泌过程的神经调控,本试验采用免疫组织化学SP法研究雌性山羊SCG中孕激素受体(PR)的分布特点。结果显示在雌性山羊的SCG中,PR免疫反应阳性产物广泛分布,在神经元胞体、施万细胞、卫星细胞、神经纤维中均有不同程度的着色。其中神经元均为PR阳性,细胞膜和细胞质呈黄褐色,PR为中等阳性,而细胞核呈棕褐色为强阳性。另外施万细胞、支持细胞和神经纤维中也有淡黄色、弱阳性的PR阳性产物。图像分析表明,神经元胞体PR的相对表达量极显著(P<0.01)高于其他非神经成分。以上结果表明雌性山羊颈前神经节是孕激素作用的主要靶器官之一,提示孕激素可能作用于SCG交感节后神经元,从而参与SCG支配的靶器官的功能活动,而SCG内神经元上的PR有可能作为一个节点协调孕激素对内脏器官的内分泌调节和自主神经对内脏器官的神经调节。     

山羊子宫内胆碱能神经分布及妊娠时的变化

采用乙酰胆碱酯酶组化法，研究了山羊子宫内胆碱能神经的分布，结果，山羊子宫颈是经较丰富，在浆膜和肌层内有神经束伴血管而行并分支分布于血管壁，在粘膜及其皱褶上皮下，粘液腺上皮有神经丛分布，妊娠时子宫颈部的神经分布与未妊娠时相比无明显变化，子宫角部神经密度均低于子宫颈部，其内环行肌层中及其与内膜交界处神经密度略高，神经束伴血管而行并分支分布于血管壁，在子宫腺上皮下及内膜上皮下无神经分布，妊夺时作胎盘内无神经分布外，仍有神经束伴血管而行交分支分布于血管壁，在分布于血管壁的神经纤维减少，结果提示，胆碱能神经主要支配山羊子宫内血管壁及颈部粘液腺上皮和粘膜上皮，妊 时子宫颈部胆碱能神经无明显变化，而子宫角内支配血管壁的胆碱能神经纤维减少。     

哺乳动物垂体前叶肽能神经支配的研究进展

应用免疫组织化学方法，对垂体前叶肽能神经支配的研究发现，在猴犬，大鼠和人等的垂体前叶有Ｐ物质，降钙素基因相关肽等免疫反应神经纤维。     

动物福利——调味剂首获关注

<正>人喜爱吃色、香、味俱全的饭菜,动物呢?动物其实与人一样,对食物的色、香、味也有感官上的要求。现代研究表明,许多动物的嗅觉神经蕾在脑部占据较大的比重,它们的嗅觉和味觉通常情况下比人类灵敏,对食物的感官判断比人要厉害得多。     

Morphology of the nerve endings in laryngeal mucosa of the horse

To discuss the significance of laryngeal sensation on various disorders of the horse, we studied the morphological and topographical characteristics of sensory structures in the laryngeal mucosa using immunohistochemistry and immunoelectron microscopy. Various sensory structures, i.e. glomerular endings, taste buds and intraepithelial free nerve endings, were found in the laryngeal mucosa by immunohistochemistry for protein gene product 9.5 (PGP 9.5) and neurofilament 200kD (NF200). Glomerular nerve endings were distributed mainly in the epiglottic mucosa; some endings were also found in the arytenoid region arising from thick nerve fibres running through the subepithelial connective tissue. Some terminals directly contacted the epithelial cells. Taste buds were distributed in the epithelium of the epiglottis and aryepiglottic fold. In the whole mount preparation, the taste buds were supplied by the terminal branching of the thick nerve fibres. In some cases, the taste buds were arranged around the opening of the duct of the epiglottic glands. The intraepithelial free nerve endings were found to be immunoreactive for substance P (SP) and calcitonin gene-related peptide (CGRP). These nerve endings were surrounded by the polygonal stratified epithelial cells in the supraglottic region, and by the ciliated cells in the subglottic region. The density of the intraepithelial free nerve endings was highest in the corniculate process of the arytenoid region and lowest in the vocal cord mucosa. The densities of CGRP- and SP-immunoreactive nerve endings in the arytenoid region were (mean +/- s.d.) 30.6+/-12.0 and 10.0+/-4.9 per unit epithelial length (1 mm), respectively and in the vocal fold mucosa, 1.1+/-0.9 and 0.8+/-0.7, respectively. Approximately one half of the CGRP immunoreactive nerve endings were immunoreactive for SP, and most SP-immunoreactive nerve endings were also immunoreactive for CGRP. Well-developed subepithelial plexus with numerous intraepithelial fibres were observed in flat or round mucosal projections that existed on the corniculate process of the arytenoid region. In conclusion, the laryngeal mucosa of the horse seems to have morphology- and/or location-dependent sensory mechanisms against various endo-and exogenious stimuli.     

The occurrence of taste buds in adults of the terrestrial ceacilian Boulengerula boulengeri Tornier, 1898 (Lissamphibia: Gymnophiona: Herpelidae)

Two generations of gustatory organs occur during amphibian ontogeny in frogs and salamanders (Anura and Caudata), and are classified as taste buds or taste discs. Taste buds are present in larval forms, whereas taste discs are typical for adults. The little research done on Gymnophiona suggests that only taste buds are present in aquatic forms (larvae and adults), and adults of the only terrestrial species studied had taste buds. Here we investigate the nature of gustatory organs in a terrestrial caecilian, Boulengerula boulengeri (Herpelidae), from Tanzania using standard light and scanning electron microscopy. We found only taste bud type organs to be present in B. boulengeri. These occur mainly in the mucosa of the front part of the oral cavity, usually near the teeth. Our results suggest that B. boulengeri possesses only one type of gustatory organ during its ontogeny.     

Taste in domestic pig, Sus scrofa

Introduction The fact that taste is not even indexed in ‘Swine Production and Nutrition’, a major textbook on swine nutrition (P ond and M aner 1984), supports the notion that taste is considered to be of no consequence in pig production. Not only does this omission underestimate the consequences of millions of years of evolution of the chemical senses, it also neglects the existence of a sensory apparatus for high taste acuity in the pig (T uckerman 1888; C hamorro et al. 1993) as will be shown in the following. Oral compounds stimulate the taste buds. In the pig, as in most mammals, these are located in fungiform papillae on the tip of the tongue, and foliate and vallate papillae on the back of the tongue. The pig differs, however, from most mammals in the number of taste buds, which exceeds most species, including the human (B radley 1971). Thus the domesticated pig possesses at least 10 000 vallate taste buds, whereas the human has 6000 (C hamorro et al. 1993), and about 4800 foliate taste buds (T uckerman 1888), compared with 3000 in human. The discrepancy between the human taste apparatus and that of the pig becomes even more evident when one compares the 1600 human fungiform taste buds with the 5000 found in pig (M iller 1986). As a result of this, the pig tongue has three to four times more taste buds than the human tongue. In humans there is a positive correlation between the number of fungiform taste buds and ability to taste (M iller and R eedy 1990; B artoshuk et al. 1996). Provided a similar relationship exists between species, with regard to number of taste buds and tasting ability, then the pig’s ability to taste is superior to that of humans. It thus seems that if it is assumed that the sense of taste plays no role in the feed consumption of pigs, the same conclusion will have to be drawn on its role in human consumption. Taste information from the fungiform taste buds is conveyed in the chorda tympani nerve (CT) and from the foliate and vallate taste buds through the glossopharyngeal nerve (NG). Recordings of nerve impulses in these nerves have been used in many species to assess a species’ ability to taste. If one considers the above data, suggesting an excellent sense of taste in the pig, coupled with the importance of unperturbed growth of the pig, one would expect a large number of recordings from the pig’s taste nerves in the literature. However, this is not the case. There are only three published studies which include recordings of the pig’s CT nerve (K itchell 1963; H ellekant 1976a, b) and one from its NG (K itchell 1963). The number of tastants used is also limited to the four standard taste stimuli: NaCl, quinine hydrochloride (QHCl), citric acid and sucrose, with the exception of an earlier study by the present authors which included thaumatin (H ellekant 1976a). No commercial feed additives nor any of the many new sweeteners, such as acesulfame-K, alitame, aspartame, etc., which, due to their high potency and pig’s sweet tooth (A umaitre 1980) could have potential use in the diet of the pig, have been included. Ten years ago one might think that data from other species could be applied to the pig’s sense of taste. However, there are large differences in the sense of taste between species. This was pointed out already by K are and K itchell some 30 years ago (K are 1960, 1961; K itchell 1963, 1965; K are et al. 1965; K are 1966) and has been increasingly documented when taste stimuli outside the usual array above have been used (J akinovich and S ugarman 1988; H ellekant and D anilova 1996; D anilova et al. 1998). For example, in an array consisting of 13 compounds that are sweet to humans, three were found to be sweet, three marginally sweet, and seven not-sweet to the pig (H ellekant and D anilova 1996). Data are presented of whole nerve and single taste fibre recordings from both the CT and NG nerves during taste stimulation with approximately 30 compounds. The data presented here show that conclusions on how a compound tastes to the pig have to be based on data acquired in pigs. Data from humans or other species are not sufficient.     

The lingual taste buds of Gallus domesticus L

The so‐called “ taste buds “ of the chicken were examined. It was found that they had one or more pores and were composed of a single cell type. There was a nerve plexus at the base of the bud giving rise to fibres which entered the bud. The cells showed acetyl cholinesterase activity and were found to degenerate following denervation. Thus they closely parallel, in both structure and neural dependency, the taste buds in other vertebrates and it is concluded that they probably are true taste buds.     

Glycoconjugate in rat taste buds.

The taste buds of the fungiform papillae, circumvallate papilla, foliate papillae, soft palate and epiglottis of the rat oral cavity were examined by lectin histochemistry to elucidate the relationships between expression of glycoconjugates and innervation. Seven out of 21 lectins showed moderate to intense staining in at least more than one taste bud. They were succinylated wheat germ agglutinin (s-WGA). Dolichos biflorus agglutinin (DBA), Bandeiraea simplicifolia lectin-I (BSL-I), Ricinus communis agglutinin-I (RCA-I), peanut agglutinin (PNA), Ulex europaeus agglutinin-I (UEA-I) and Phaseolus vulgaris agglutinin-L (PHA-L). UEA-I and BSL-I showed moderate to intense staining in all of the taste buds examined. They strongly stained the taste buds of the epiglottis, which are innervated by the cranial nerve X. UEA-I intensely stained the taste buds of the fungiform papillae and soft palate, both of which are innervated by the cranial nerve VII. The taste buds of circumvallate papilla and foliate papillae were innervated by the cranial nerve IX and strongly stained by BSL-I. Thus, UEA-I and BSL-I binding glycoconjugates, probably alpha-linked fucose and alpha-D-galactose, respectively, might be specific for taste buds. Although the expression of these glycoconjugates would be related to the innervation of the cranial nerve X, the differential expression of alpha-linked fucose and alpha-D-galactose might be related to the innervation of the cranial nerve VII and IX, respectively.     

Gross and microscopic observations on the lingual structure of the Florida Manatee Trichechus manatus latirostris

The tongue of the Florida manatee (Trichechus manatus latirostris) was studied macroscopically, light and electron microscopically. The tongue was slender, muscular and firmly fixed in the oral cavity; only the cranial tip was free and mobile. Numerous filiform papillae were distributed over the dorsal surface of the rostral tongue. Multiple raised, round fungiform-like papillae were distributed over most of the dorsum. Typical fungiform papillae were restricted to the lateral margins of the tongue. Foliate papillae, presenting as multi-fossulate openings, were noted on the caudolateral margins. Open pits were located on the dorsocaudal surface and lateral walls. Microscopic examination showed that most of the lingual dorsum was covered with a thick stratified squamous epithelium. Open pits led to well-developed mucous salivary glands. Glands within the foliate papillae were mostly mucous, although some seromucous glands were present. Taste buds were restricted to the epithelium of the foliate papillae. Throughout the tongue, striated muscle was abundant below the epithelium. Blood vessels, lymph channels and nerve fibres were freely distributed throughout the intermuscular stroma. Nerve fibres reacted positively with neurone specific enolase (NSE) antibody throughout the tongue, including nerve bundles, glands and taste buds. Clear to translucent vacuoles were found juxtaposed to nuclei in the stratum spinosum in the foliate papillae epithelium.     

Innervation of the circumvallate papilla of the cat tongue

Immunohistochemically, the distribution of S-100 protein and acetylated tubulin-positive nerve fibres was studied in the circumvallate papilla and its taste buds (TB) in the adult cat. The immunostaining for acetylated tubulin demonstrated an extensive innervation of the circumvallate papilla. Vegetative ganglionic cells were found in the central area of papilla, whereas fine nerve fibres were concentrated under epithelium. Individual positive axons were seen in relation to TB. Nerve fibres enter the TB and branch out among the supporting and sensory cells. Some nerve fibres reach the apical surface of the TB, including the taste pore. Nerve fibres positive for S-100 protein were observed as dense nerve plexus located in the core of the papilla. Satellite cells localized inside the papilla were seen to surround the ganglionic cells. Bands of fine nerve fibres were present under lining epithelium, mainly at the base of the TB. A weak reaction was displayed by taste bud cells and surrounding epithelial cells as well as by the epithelial cells of the papillary side of the moat. A dense network of the nerve fibres was present among the glandular acini and surrounding the ducts of the serous Ebner's glands.     

苦味受体的生物学特征、信号转导机制及苦味剂和苦味抑制剂对苦味受体的影响

苦味受体(bitter taste receptors,TAS2Rs)是一种G-蛋白偶联受体(GPCR),由30个基因组成的基因家族编码。苦味可使动物远离有毒有害物质,当动物尝到苦味物质时,会刺激舌头的味蕾中味觉受体细胞表达TAS2Rs,进而引发下游一系列信号转导反应,最终通过鼓索神经和舌咽神经将信息整合传到大脑,使动物产生厌恶的感觉,从而选择拒绝摄入这些苦味物质。本文就TAS2Rs的生物学特征、信号转导机制及苦味剂和苦味抑制剂对苦味受体的影响进行简要综述。     

Taste

Taste has a dual role. Like other senses it informs the individual about the external world, but unlike other senses it connects that perception with information about the internal environment. The principal function of taste is similar in all higher species. Molecules act on specialized sensory cells (= taste cells) in various regions of the oral cavity thus triggering signals, which are relayed to the cortex via afferent nerves, the caudal hindbrain and the thalamus. Taste afferents also reach the hypothalamus and the limbic system. The taste of food triggers physiological and behavioral reactions in man and animals. Stimulation of taste cells immediately elicits salivation, secretion of gastric acid and pancreatic juice as well as secretion of gastrointestinal and pancreatic hormones. Innate and learned taste preferences or aversions play an important role in food selection and taste aversions are considered to be reliable indicators of malaise. Neural signals from the periphery or humoral factors which are sensed by receptors in the central nervous system both can change the acceptance of a certain taste. Endogenous opiates in the brain seem to play a special role in the modulation of taste perception. The amygdala is apparently a brain area which is particularly important for taste perception.     

Morphological Study of the Persian Leopard (Panthera pardus saxicolor) Tongue

This study described the morphological features of the Persian leopard (Panthera pardus saxicolor) tongue using light and scanning electron microscopy techniques. The keratinized filiform papillae were distributed all over the entire dorsal surface of the tongue and contained small processes. They were changed into a cylindrical shape in the body and conical shape in the root. The fungiform papillae were found on the apex and margin of the tongue. Few taste pores were observed on the dorsal surface of each papilla. The foliate papillae on the margins of the tongue were composed of several laminae and epithelial fissures. Taste buds were not seen within the non‐keratinized epithelium. The vallate papillae were six in total and arranged in a “V” shape just rostral to the root. Each papilla was surrounded by a groove and pad. Taste buds were seen within their lateral walls. Lyssa was visible on the ventral surface of the tongue tip and was found as cartilaginous tissue surrounded by thin connective tissue fibres. The core of the tongue was composed of lingual glands, skeletal muscle and connective tissue. These glands were confined to the posterior portion of the tongue and were composed of many serous cells and a few mucous cells. The results of this study contributed to the knowledge of the morphological characteristics of the tongue of wild mammals and provided data for the comparison with other mammals.