人的味觉

人的单个菌状乳头在辨别原发性味觉的种类时,与其所含有的味蕾数有关。在哺乳动物舌体上的轮廓乳头,叶状乳头和菌状乳头均含有味蕾。位于舌体背面前部的菌状乳头,因其易于定位又易与其他组织分开,所以成为研究味觉的最方便的实验组织。由于对单个乳头是否能反应出一种以     

味蕾失神经后的研究进展

味蕾是人体的味觉感受器官,研究发现味蕾的发生发展与味觉神经有着重要的联系。味觉神经损伤或缺失会引起味蕾发生一系列的改变,现就味蕾失神经后的形态、功能以及相关因子的改变作一综述。     

舌上皮味蕾功能性再生方法及机制的研究进展

味觉是人类重要感官, 由增龄变化、舌癌手术、放化疗等引起的味觉功能障碍可影响人生活质量, 味蕾再生需求逐渐得到关注。目前, 关于味觉细胞发育及更新的基础研究为味蕾再生提供了理论基础;了解味蕾再生的分子机制有助于获悉准确的作用靶点;神经再生、组织工程、细胞因子疗法等新方法试图实现味蕾的功能性再生并加速其临床转化。本文围绕舌上皮味蕾再生机制及最新的组织工程学方法进行综述, 以期为味觉损伤疾病的预防和治疗提供参考, 为味蕾再生提供依据。     

味觉受体信号转导机制及对微生物的调控

口腔味蕾细胞中的味觉受体有助于机体鉴别营养物质和有害物质,对哺乳动物的生存具有重要意义。近年来发现,味觉受体及其下游信号转导通路还在呼吸道、大脑、胃肠道等多种组织细胞中表达。表达味觉受体的细胞统称为化学感官细胞,在抵抗微生物感染、调节营养吸收、维持内环境稳态中发挥重要作用。目前已发现多种组织细胞中的味觉受体可识别细菌等微生物,介导宿主免疫应答反应,在感染性疾病发生发展过程中起到重要作用。本文就味觉受体的信号转导机制及其对微生物的调控作用进行综述。     

味觉研究的进展

关于味觉,国内的解剖和生理书籍记述简单,也未看到这方面的研究文献、专著或综述。而在国外,关于味觉研究的方法多样,范围广泛,并取得了较大的进展,现综述如下。一、味觉感受器接受味道刺激的感受器是味蕾,正常成人约有1万个,主要分布舌背的轮廓乳头,菌状乳头和叶状乳头内(图1),在腭下面、咽腭弓、会厌、咽后壁的粘膜上皮内也有味蕾,舌背中部和舌下     

哺乳动物的外周味觉受体和信号转导及调节机制

味觉是一种极为复杂和重要的感觉。哺乳动物借助高度敏感专一的味觉感受器,对外界环境中的化学物质进行识别、探寻食物和调节食欲并作出相应的好恶甚至规避性的行为应答。味觉信号转导机制是目前口腔基础研究领域的热点和难点。在过去的数年里,味觉受体、信号转导及调节机制受到了极大的关注,本文就味觉细胞的类型和功能、外周味觉受体及信号转导机制、外周味觉信号调节机制研究进展作一综述。     

更年期味觉障碍的临床研究

目的：探讨更年期味觉障碍和舌菌状乳头、味觉功能之间的关系。方法：通过不同浓度柠檬酸溶液，检测全口发现阈值、强度比较能力和菌状乳头形态和数量。结果：味觉障碍组全口发现阈值显著高于健康对照组，对酸强度的敏感性和分辨能力显著下降，菌状乳头数目两组无明显差异。结论：味觉障碍的发生可能与菌状乳头所含味蕾细胞退化以及女性内分泌改变有关。     

口腔粘膜的老化现象

老年人口腔粘膜的上皮角化和厚度,都随年龄而增加。舌粘膜乳头亦逐渐消失,舌表面变为光滑,舌乳头味蕾数明显减少。20岁左右平均为245个味蕾,74～85岁则减少为88个。对于咸、甜的味觉,也随年龄而显著降低,但对于酸、苦的味觉,并不发生任何变化。唾液分泌量及其成分浓度,也随年龄增长而降低,65岁之后,唾液酶的活动量,可减少75%,这是由于腺细胞萎缩和腺导管上皮细胞变性所致。腺组织亦随年龄趋向     

人味蕾的味孔、味凹的超微结构观察

目的观察成人舌味蕾的味孔、味凹的三维超微结构。方法未受病变累及的成人轮廓乳头3例，每例标本一分为二，在扫描电镜下行连续超薄切片、染色后，在透射电镜下观察轮廓乳头处味蕾。结果味孔孔径约1．02～7．36μm，孔内味毛、致密物少见，味凹呈三角形。结论舌轮廓乳头处多数味孔内无味毛和致密物。味孔形态与数量与味觉功能密切相关。     

老年营养——食欲中味觉和嗅觉的作用

即使是技术很熟练的矫形医生,仍然会发现某些病人(通常是老年病人)不能适应精细制作的义齿修复。老年人义齿失败的主要原因是由于不适当的营养而造成的组织耐力不足。众所周知,老年人吃的少,经常营养失调。因此,矫形医生对老年病人的饮食及食物习惯进行指导是必要的。味觉和嗅觉不可避免地与食物的美味可口联在一起。随着年龄的增长,味觉和嗅觉的功能普遍降低,至使老年人常常患食欲减退。这是鼻顶部嗅觉感受器与舌味蕾变性引     

舌神经切断吻合后菌状乳头味蕾再生的实验研究

目的：了解舌神经损伤后味蕾的变化，以及切断的舌神经用神经外膜吻合修复后舌菌状乳头和味蕾的再生能力。方法：模拟临床将SD大鼠一侧舌神经钳夹或切断损伤，即刻用神经外膜吻合的方法修复切断的舌神经．分别于术后20d和100d时用体视显微镜、组织显微镜、扫描电镜观察鼠舌菌状乳头和味蕾的形态和数目。结果：术后20d时，无论钳夹损伤或切断舌神经，切断的舌神经无论是否用神经吻合修复，舌神经损伤侧的菌状乳头和味蕾均萎缩、退化，数目明显减少；术后100d时，舌神经钳夹损伤和舌神经切断后即刻吻合修复的动物，退化、萎缩的菌状乳头和味蕾已完全再生，形态和数目恢复正常。而舌神经切断后未吻合的动物，萎缩、退化的菌状乳头和味蕾无明显再生恢复。结论：钳夹损伤舌神经，萎缩、退化的菌状乳头和味蕾可以自行再生恢复；切断舌神经，萎缩、退化的菌状乳头和味蕾不能自行再生恢复；用神经外膜吻合修复后，萎缩、退化的菌状乳头和味蕾可以再生恢复。舌菌状乳头和味蕾形态、数目的再生恢复，可以作为舌神经修复成功的客观指标。     

Quantitative study of taste bud distribution within the oral cavity of the postnatal mouse

The aim of this study was to investigate the age-related developmental changes of taste bud distribution within the subpopulations at different postnatal ages in the mouse oral cavity.

Developmental changes of taste bud distribution on the soft palate, fungiform, foliate and circumvallate papillae in the mouse oral cavity were examined histologically at different postnatal ages. After paraffin embedding, complete serial sections at 10 μm thickness were made and stained by routine hematoxylin–eosin staining methods. Digitised images for each section were examined carefully. The existence of a taste pore was used to identify mature taste buds. A two-way analysis of variance (group versus age) was used to analyse differences in taste bud number and characteristics for each of the developmental changes. An independent measures t-test was used to compare two means. No taste buds with pores were observed at birth within circumvallate and foliate papillae. However, 61% of the circumvallate and 58% of the foliate taste buds contained taste pores at 2 weeks after birth. In contrast, at birth, 55% of the taste buds on the soft palate and only 22% of the taste buds within fungiform papillae contained taste pores. Then, the number of mature taste buds (taste buds with pores) increased rapidly 1 week after birth, resulting in 90% of soft palate taste buds and 32% of fungiform taste buds containing taste pores.

These results suggests that the earlier maturation of soft palate taste buds compared with the other populations in the oral cavity raises evidence of their significant role in the taste mechanism, especially in the early life of the mouse.     

~(60)Co照射对大鼠舌菌状乳头及味蕾的影响

目的　研究临床治疗剂量60Co照射头颈部恶性肿瘤后,舌菌状乳头及其味蕾的形态学变化和再生能力。方法　模拟临床治疗剂量,根据多次照射剂量归一的原则,一次大剂量60Co照射30只SD大鼠头颈部,照射后观察大鼠舌菌状乳头和味蕾的变化。结果　照射后大鼠舌菌状乳头和味蕾第5天明显萎缩、退化、消失,第10~20天达到最高峰,第30天有少量菌状乳头和味蕾开始再生,第60天菌状乳头和味蕾明显再生,有部分菌状乳头仍呈萎缩状,未见到再生的味蕾。结论　治疗剂量的60Co照射头颈部,舌菌状乳头和味蕾的损伤是极其严重的,这些损伤能够再生,但不完全。     

Location and variation in number of taste buds in human fungiform papillae

Abstract – Serial sections of 182 human fungiform papillae, obtained at autopsy from 22 individuals aged 2 days to 90 years, were examined by light microscopy with regard to location and number of taste buds. The taste buds were always found on the convex, dorsal surface of the papillae but otherwise failed to display any preferential location pattern. A total of 262 taste buds, an average of 1.4 per papilla, were found. However, there was considerable variation in the occurrence of taste buds, both from papilla to papilla and from case to case. While the number of taste buds in a single papilla varied from 0 to 27, 63% of the papillae had no taste buds at all, 26% had 1–3 buds and the remainder 4 or more buds. The mean number of taste buds per papilla varied from 0 to 9 between individuals; no dependence upon sex or age could be demonstrated for this variation. The significance of these anatomical findings with regard to physiological studies on taste involving the fungiform papillae is discussed.     

Age-related changes in renewal of taste bud cells and expression of taste cell-specific proteins in mice

It is known that taste sensitivities change throughout life and they decline with aging. We have also found that both detection and recognition thresholds of taste were significantly elevated in aged persons, while oral somatic sensations hardly changed. To elucidate the peripheral mechanisms of the decline of taste sensitivities with age, we first investigated age-associated changes in cell renewal of taste buds in the circumvallate papillae of ddY mice, because one of the major characteristic differences of taste receptors from somatosensory receptors is a continual turnover of cells. In addition, we examined the expression patterns of taste cell-specific proteins such as protein gene products 9.5 (PGP 9.5) and gustducin, and ultrastructure of taste buds which may change resulting from the change of turnover rate. As a reference, we also used mice in the developing stage. The rate of cell renewal was examined using 5-bromo-2'-deoxyuridine (BrdU), which is incorporated in DNA during the S-phase of cells. BrdU and the proteins were detected immunohistochemically and the ultrastructure was investigated by electron microscopy. The aged mice demonstrated a delayed cell renewal and highly vacuolated cytoplasm in taste buds, while they showed no change in PGP 9.5-immunoreactive cells and an increase in gustducin-immunoreactive cells compared with young adult mice. In contrast, the developing mice showed a higher rate of cell turnover and rapid increase of PGP 9.5- and gustducin-immunoreactive cells reaching the mature level in 3 weeks after birth. The changes observed in the present study in aged mice may be related to the decline in taste sensitivity with aging.     

Location and variation in number of taste buds in human fungiform papillae.

Serial sections of 182 fungiform papillae, obtained at autopsy from 22 individuals aged 2 days to 90 years, were examined by light microscopy with regard to location and number of taste buds. The taste buds were always found on the convex, dorsal surface of the papillae but otherwise failed to display any preferential location pattern. A total of 262 taste buds, an average of 1.4 per papilla, were found. However, there was considerable variation in the occurrence of taste buds, both from papilla to papilla and from case to case. While the number of taste buds in a single papilla varied from 0 to 27, 63% of the papillae had no taste buds at all, 26% had 1-3 buds and the remainder 4 or more buds. The mean number of taste buds per papilla varied from 0 to 9 between individuals; no dependence upon sex or age could be demonstrated for this variation. The significance of these anatomical findings with regard to physiological studies on taste involving the fungiform papillae is discussed.     

Hormones and bioactive substances that affect peripheral taste sensitivity

Taste receptor cells in taste buds detect chemical compounds in foods and drinks and transmit these signals through gustatory nerve fibers to the central nervous system. Sensory signals of taste are essential for animal feeding behavior; animals prefer sweet taste and avoid bitter and sour tastes. Recent studies have demonstrated that the sensitivity of taste receptor cells to tastants is not constant but is subject to regulation by hormones and bioactive substances, such as leptin and endocannabinoids. Leptin selectively suppresses sweet taste sensitivity. In contrast, endocannabinoids selectively enhance sweet taste sensitivity. Both types of signaling molecules act at their respective receptors in sweet-sensitive taste cells. In addition, glucagon-like peptide-1 (GLP-1), glucagon, oxytocin, insulin, cholecystokinin, neuropeptide Y, and vasoactive intestinal peptide (VIP) have been implicated in the regulation of peripheral taste sensitivity. In this review, the hormones and bioactive substances that affect peripheral taste sensitivity are summarized. Regulation of peripheral taste sensitivity by hormones and bioactive substances may play an important role in the control of feeding behavior and maintenance of energy, ion, and amino acid homeostasis in animals.     

Depressed taste and smell in geriatric patients

BACKGROUND: Geriatric patients have a number of dental care problems that younger patients do not encounter. The oral changes associated with aging can have a significant effect on the efficacy of dental treatment. TYPES OF STUDIES REVIEWED: The authors reviewed studies dealing with the causes of depressed sense of taste and smell; the causes included aging, disease, medications and dental problems. Based on their findings, the authors described the location and anatomy of taste buds and receptor cells for smell and explored appetite, saliva, food seasonings, nutrition and dietary recommendations. They also discussed the relationship of smoking and tongue cleaning to taste sensations. RESULTS: The authors found that considerable differences exist between elderly people and young people in regards to sensory perception and pleasantness of food flavors. Salt and bitter taste acuity declines with age, but sweet and sour perceptivity does not. Olfactory acuity also declines with age. The authors found that most of the studies reviewed suggested that the sense of smell is more impaired by aging compared with the sense of taste. Smoking diminishes the taste of food and makes flavorful foods taste flat, while tongue brushing can increase taste sensation for geriatric patients. CLINICAL IMPLICATIONS: Food can become tasteless and unappetizing for geriatric patients as the result of declining taste and smell perception. Geriatric patients should be encouraged to add seasonings to their food instead of relying on excessive consumption of salt and sugar to give their food flavor. Adequate nutrition, tongue cleaning and smoking cessation are recommended for geriatric dental patients.     

The occurrence of taste buds in the palate of human adults as evidenced by light microscopy.

There is some uncertainty in the literature as to the existence of taste buds in the palate of the human adult. In those histologic studies in which the ages of the individuals have been reported, taste buds have not been found in the palates of adults, but have been found in fetuses or newborn. However, clinical studies have demonstrated taste perception in the palate of the human adult. Thus, the aim of the present study was to attempt to find taste buds in the human palate in subjects of different ages. In serial sections of selected areas of the palatal mucosa from autopsy material from individuals 0--80 years of age no taste buds could be demonstrated. However, in four of seven subjects aged 25--44 years, one or two taste buds were found in biopsies from areas of the soft palate where taste perception had been demonstrated clinically just prior to excision. Thus the present study indicates that scattered taste buds exist also in the soft palate of human adults.