Current Pharmaceutical Design - Volume 20, Issue 16, 2014

Taste receptors function as one of the interfaces between internal and external milieus. Taste receptors for sweet and umami (T1R [taste receptor, type 1]), bitter (T2R [taste receptor, type 2]), and salty (ENaC [epithelial sodium channel]) have been discovered in the recent years, but transduction mechanisms of sour taste and ENaC-independent salt taste are still poorly understood. In addition to these five main taste Read More

In the oral cavity, taste receptor cells dedicate to detecting chemical compounds in foodstuffs and transmitting their signals to gustatory nerve fibers. Heretofore, five taste qualities (sweet, umami, bitter, salty and sour) are generally accepted as basic tastes. Each of these may have a specific role in the detection of nutritious and poisonous substances; sweet for carbohydrate sources of calories, umami for protein and Read More

A number of nutrient sensing seven trans-membrane (7TM) receptors have been identified and characterized over the past few years. While the sensing mechanisms to carbohydrates and free fatty acids are well understood, the molecular basis of amino acid sensing has recently come to the limelight. The present review describes the current status of promiscuous L-α-amino acid sensors, the calcium sensing receptor (CaSR), Read More

Nausea and vomiting are biological systems for defense against food poisoning that are also provoked by numerous drugs (e.g., chemotherapy, anesthesia) and chronic diseases (e.g., cancer, diabetic gastroparesis). The sensory pathways that stimulate nausea and vomiting include vestibular, area postrema, and forebrain inputs, but gastrointestinal vagal afferent fibers arguably play the most prominent role as a firs Read More

Digestion and the absorption of food and nutrients have been considered the only functions of the gastrointestinal (GI) tract. However, recent studies suggest that taste cells in the oral cavity and taste-like cells in the GI tract share many common characteristics (taste receptors and transduction signaling). Over the last two decades, it has been revealed that the GI tract is a chemosensory organ that transfers nutrien Read More

Pavlov’s seminal findings in the early twentieth century showed that the sight, smell or taste of food in dogs with chronic esophagostomy induces a vagal-dependent gastric acid secretion. These observations established the concept of the cephalic phase of digestion. Compelling experimental evidence in rats indicates that the three amino acid peptide thyrotropin-releasing hormone (TRH) expressed in the brainstem plays a ke Read More

In the stomach, pre-absorptive perception of food constituents is of particular importance in maintaining secretion and motility that matches the quantity and quality of nutrients. Products of food protein hydrolysis, free amino acids and short peptides, are the most potent chemical stimulants of the gastric phase of digestion. They are recognized by a variety of extracellular receptors belonging to the G-protein-coupled recepto Read More

Nutrient perception in the gut is important for the maintenance of nutrient and energy balance in the body. Recently, nutrient perception has attracted the attention of medical researchers, as it may provide an opportunity to prevent obesity and associated disease. Recent progress in functional MRI (fMRI) techniques have enabled noninvasive investigation of whole brain function during the processing of information re Read More

Neurons and neuroendocrine cells store nucleotides in vesicles and release them upon stimulation, leading to intercellular purinergic signaling. The molecular machinery responsible for the vesicular storage of nucleotides was a long standing enigma, however, recently the transporter involving in the process was identified. This article summarizes the history of vesicular storage of nucleotides and the identification of the vesicula Read More

Our newly developed umami taste sensitivity test revealed the loss of only the umami taste sensation in some elderly patients, whereas the other four basic taste sensations (sweet, salty, sour, bitter) were normal. Such patients all complained of appetite loss and weight loss, resulting in poor overall health. As a treatment for taste disorder patients, improvement of salivary flow has been adopted in our clinic. Umami taste stim Read More

Despite the development of strong antibiotics, the pneumonia death is increasing all over the world in these decades. Among the people who died of pneumonia, the majority were 65 years old or over. Although pneumonia is recently categorized into several entities, aspiration pneumonia includes all entities. Therefore, targeting dysphagia and aspiration to treat pneumonia is a promising strategy and anti-aspiration drugs Read More

Intestinal chemosensing of endogenous and exogenous luminal compounds, including acid, CO2, bile acids and nutrients is an emerging area of gastrointestinal research, since gut hormones, particularly including incretins and glucagon-like peptide-2 (GLP-2) are released in response to luminal nutrients. Identification of luminal chemosensors such as nutrient-ligand G-protein coupled receptors (GPCRs) in enteroendocrin Read More

The colonic lumen is continually exposed to many compounds, including beneficial and harmful compounds that are produced by colonic microflora. The intestinal epithelia form a barrier between the internal and luminal (external) environments. Chemical receptors that sense the luminal environment are thought to play important roles as sensors and as modulators of epithelial cell functions. The recent molecular i Read More

Digestive tract motility patterns are closely related to the pathophysiology of functional gastrointestinal diseases (FGID), and these patterns differ markedly between the interdigestive period and the postprandial period. The characteristic motility pattern in the interdigestive period is so-called interdigestive migrating contraction (IMC). IMCs have a housekeeping role in the intestinal tract, and could also be related to FGID. IMCs Read More

We reviewed the prophylactic effect of monosodium glutamate (MSG), a substance known as the “umami”, on NSAIDinduced small intestinal damage in rats. Loxoprofen, one of the NSAIDs frequently used in Asian countries, given orally at 60 mg/kg, caused hemorrhagic damage in the small intestine, mainly jejunum and ileum, concomitant with a down-regulation of Muc2 expression/ mucus secretion and an up-regulatio Read More

The principal objective of this paper is to demonstrate the role of taste and flavor in health from the ancient science of Ayurveda to modern medicine; specifically their mechanisms and roles in space medicine and their clinical relevance in modern heath care. It also describes the brief history of the use of the monosodium glutamate or flavor enhancers (“Umami substance”) that improve the quality of food intake by sti Read More