Albertino Bigiani

Università degli Studi di Modena e Reggio Emilia | UNIMO · Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze

Synopsis Sodium chloride elicits a specific sensation called salt taste. Sodium ion (Na⁺) is the main contributor to the perceived saltiness. The detection of this mineral in foodstuffs is made possible by the activity of specific sensory elements in the oral cavity, the taste cells. At this level, Na⁺ is transformed (transduced) into biological si...

Taste reception is fundamental for the proper selection of food and beverages. Among the several chemicals recognized by the human taste system, sodium ions (Na+) are of particular relevance. Na+ represents the main extracellular cation and is a key factor in many physiological processes. Na+ elicits a specific sensation, called salty taste, and lo...

Salt (NaCl) is an essential nutrient for it allows maintaining a stable level of Na + in the extracellular fluid. This condition is required by many physiological processes, which would be otherwise compromised by sodium deficiency. To recognize salt in food and beverages, we rely on specific chemical detectors provided by taste and somatosensory s...

Key points: Taste cells are sensory receptors that undergo continuous turnover while they detect food chemicals and communicate with afferent nerve fibers. The voltage-gated sodium current (INa ) is a key ion current for generating action potentials in fully differentiated and chemo-sensitive taste cells, which use electrical signaling to release...

Kokumi taste-active compounds enhance salty taste perception. In animal models, sodium (salt) detection is mediated by the amiloride-sensitive epithelial sodium channel, ENaC. This ion channel works as a sodium receptor in the so-called sodium-taste cells. It is not known whether kokumi taste substances are able to affect the activity of functional...

A central hypothesis on brain functioning is that long-term potentiation (LTP) and depression (LTD) regulate the signals transfer function by modifying the efficacy of synaptic transmission. In the cerebellum, granule cells have been shown to control the gain of signals transmitted through the mossy fiber pathway by exploiting synaptic inhibition i...

The investigation of synaptic functions remains one of the most fascinating challenges in the field of neuroscience and a large number of experimental methods have been tuned to dissect the mechanisms taking part in the neurotransmission process. Furthermore, the understanding of the insights of neurological disorders originating from alterations i...

The brain functions can be reversibly modulated by the action of general anesthetics. Despite a wide number of pharmacological studies, an extensive analysis of the cellular determinants of anesthesia at the microcircuits level is still missing. Here, by combining patch-clamp recordings and mathematical modeling, we examined the impact of sevoflura...

This is a reprint of articles from the Special Issue published online in the open access journal Nutrients (ISSN 2072-6643) (available at: https://www.mdpi.com/journal/nutrients/special_issues/Salt_Taste).

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current pandemic of coronavirus disease 2019 (COVID-19). This pandemic is characterized by a high variability in death rate (defined as the ratio between the number of deaths and the total number of infected people) across world countries. Several possible explanati...

The sodium ion (Na+) is essential for life[…]

Synaptic plasticity is the cellular and molecular counterpart of learning and memory and, since its first discovery, the analysis of the mechanisms underlying long-term changes of synaptic strength has been almost exclusively focused on excitatory connections. Conversely, inhibition was considered as a fixed controller of circuit excitability. Only...

Multiphoton microscopy is the most widespread method for preclinical brain imaging when sub-micrometer resolution is required. Nonetheless, even in the case of optimal experimental conditions, only a few hundred micrometers under the brain surface can be imaged by multiphoton microscopy. The main limitation preventing the acquisition of images from...

Neural inhibition plays a key role in determining the specific computational tasks of different brain circuitries. This functional "braking" activity is provided by inhibitory interneurons that use different neurochemicals for signaling. One of these substances, somatostatin, is found in several neural networks, raising questions about the signific...

Human dental pulp is considered an interesting source of adult stem cells, due to the low-invasive isolation procedures, high content of stem cells and its peculiar embryological origin from neural crest. Based on our previous findings, a dental pulp stem cells sub-population, enriched for the expression of STRO-1, c-Kit, and CD34, showed a higher...

The induction of long-term potentiation and depression (LTP and LTD) is thought to trigger gene expression and protein synthesis, leading to consolidation of synaptic and neuronal changes. However, while LTP and LTD have been proposed to play important roles for sensori-motor learning in the cerebellum granular layer, their association with these m...

Salt reception by taste cells is still the less understood transduction process occurring in taste buds, the peripheral sensory organs for the detection of food chemicals. Although there is evidence suggesting that the epithelial sodium channel (ENaC) works as sodium receptor, yet it is not clear how salt-detecting cells signal the relevant informa...

Significance The plasticity of inhibitory synapses is involved in regulating the balance between excitation and inhibition. Although a wide range of plastic mechanisms was analyzed in GABAergic synapses, a bidirectional plasticity engaged by NMDA signaling has never been observed. We report here that the synapse between Golgi cells and granule cell...

Sodium intake is important to maintain proper osmolarity and volume of extracellular fluid in vertebrates. The ability to find sources of sodium ions for managing electrolyte homeostasis relies on the activity of the taste system to sense salt. Several studies have been performed to understand the mechanisms underlying Na + reception in taste cells...

Smoking has been recognized as one agent that may decrease the effectiveness of the gustatory system to detect salt (Na+) in foodstuffs. As a consequence, smokers tend to ingest saltier foods than nonsmokers. An increase in sodium intake has been associated with hypertension: thus, smoking may concur to the development of hypertension by impairing...

Although general anesthetics are thought to modify critical neuronal functions, their impact on neuronal communication has been poorly examined.We have investigated the effect induced by desflurane, a clinically used general anesthetic, on information transfer at the synapse between mossy fibers and granule cells of cerebellum, where this analysis...

Many studies have demonstrated that chronic exposure to nicotine, one of the main components of tobacco smoke, has profound effects on the functionality of the mammalian taste system. However, the mechanisms underlying nicotine action are poorly understood. In particular no information is available on the chronic effect of nicotine on the functioni...

Our ability to sense chemicals occurring in food and beverages relies on the operation of specialized epithelial cells called taste cells, found as clusters (taste buds) mainly in the oral cavity. Unlike other sensory cells, such as hair cells in the cochlea, taste cells differ from each other in terms of structural features. At least three main mo...

Palytoxin-group toxins (PlTX) exert their potent biological activity by altering mechanisms of ion homeostasis in excitable and non-excitable tissues. This review will describe major aspects that led to the relatively early identification of the Na(+),K(+)-ATPase as the molecular target and receptor of the toxin in sensitive systems. The importance...

Three experiments were performed to verify whether melatonin (MEL) may influence hoarding behavior in rats. This hypothesis was supported by the consideration that leptin treatment decreases food hoarding in hamsters and that an inverse relation exists between plasma leptin concentration and MEL treatment. Male Sprague-Dawley rats housed individual...

Recent studies have shown that taste cells transducing bitter, sweet, and umami stimuli do not possess high-threshold voltage-gated calcium channels required for synaptic transmission at conventional synapses, suggesting some sort of signal processing inside taste buds prior to the activation of nerve endings. To evaluate whether this is a general...

Nicotine, an alkaloid found in tobacco smoke, has been recognized as capable of inducing changes in taste functionality in conditions of chronic exposure. The mechanisms underlying these sensory alterations, however, are currently unknown. We addressed this issue by studying the long-term effects of nicotine on the anatomical features of taste buds...

The marine dinoflagellate Gambierdiscus toxicus produces highly lipophilic, polycyclic ether toxins that cause a seafood poisoning called ciguatera. Ciguatoxins (CTXs) and gambierol represent the two major causative agents of ciguatera intoxication, which include taste alterations (dysgeusiae). However, information on the mode of action of ciguater...

The cholinergic anti-inflammatory pathway has not yet been studied in splanchnic artery occlusion (SAO) shock. We investigated whether electrical stimulation (STIM) of efferent vagus nerves suppresses the inflammatory cascade in SAO shock. Animals were subjected to clamping of the splanchnic arteries for 45 min, followed by reperfusion. This surgic...

A vagus nerve-mediated, brain cholinergic protective mechanism activated by melanocortin peptides is operative in conditions of circulatory shock; moreover, there is anatomical evidence of dual vagal-cardiac efferent pathways in rats, which could play different roles in controlling heart function. Therefore, we investigated the role and functional...

This paper presents the first results of a computational analysis of the noise associated with ion current in single open ion channels. This analysis is performed by means of a coupled Molecular Dynamics-Monte Carlo approach able to simulate the conduction process on the basis of all microscopic information today available from protein structural d...

Taste receptor cells (TRCs) represent an unique opportunity to study a dynamic population of excitable cells that undergoes two basic neurobiological processes: postnatal development and cell turnover. We have begun to investigate the functional properties of TRCs and how they mature over time by applying the patch-clamp technique to single cell in...

Ciguatera is a food poisoning caused by toxins of Gambierdiscus toxicus, a marine dinoflagellate. The neurological features of this intoxication include sensory abnormalities, such as paraesthesia, heightened nociperception, and also taste alterations. Here, we have evaluated the effect of gambierol, one of the possible ciguatera toxins, on the vol...

A physical model and a simulation framework are proposed for the analysis of conduction properties of ion channels. The permeation path of ions along the channel is defined through the simultaneous occupancy of a set of individual ion binding sites within the pore identified from structural X-ray data and Molecular Dynamics (MD) simulations. All pe...

Some theoretical aspects on structure and function of proteins have been discussed previously. Proteins form multimeric complexes, as they have the capability of binding other proteins (Lego property) resulting in multimeric complexes capable of emergent functions. Multimeric proteins might have either a genomic or a postgenomic origin. Proteins sp...

Pheromonal communication is the most convenient way to transfer information regarding gender and social status in animals of the same species with the holistic goal of sustaining reproduction. This type of information exchange is based on pheromones, molecules often chemically unrelated, that are contained in body fluids like urine, sweat, speciali...

Glutamate plays a double role in the physiology of TRCs. As a free-occurring component of some foodstuff, glutamate is detected by TRCs and conveys information about the presence of protein-rich source. As a substance released by TRC and/or nerve endings, it is involved in cell-to-cell communication at chemical synapses in taste organs. In both cas...

Taste transduction relies on the activity of several membrane proteins, including ion channels. In this study, we have found evidence for the occurrence of a specific class of potassium channels in taste cells, the so-called KCNK channels. According to our electrophysiological data, taste KCNK channels are sensitive to protons and to hyper osmotic...

The aim of this work is to study the conduction properties of selective ion channels by means of a Monte Carlo simulation that yields both current and its noise under open-gate conditions. A multi-ion model is used, where the ion binding sites around and inside the protein, the allowed transitions between different occupancy states and the associat...

My current research focuses on molecular mechanisms underlying host immune defense of pathogenic bacteria. I want to understand the role of chemosensory receptors that are used by the immune and sensory system to detect the presence of bacterial metabolites.

Somatostatin-14 (SRIF) and its receptors (sst(1-5)) are found in the mammalian retina. However, scarce information is available on the role of the somatostatinergic system in retinal physiology. We have recently used gene-knockout technology to gain insights into the function of sst(1) and sst(2) receptors in the mouse retina. The sst(1) receptor l...

Several melanocortin peptides have a prompt and sustained resuscitating effect in conditions of hemorrhagic shock. The transcription nuclear factor kappaB (NF-kappaB) triggers a potentially lethal systemic inflammatory response, with marked production of tumor necrosis factor-alpha (TNF-alpha), in hemorrhagic shock. Here we investigated whether the...

Taste reception is fundamental for proper selection of food and beverages. Chemicals detected as taste stimuli by vertebrates include a large variety of substances, ranging from inorganic ions (e.g., Na(+), H(+)) to more complex molecules (e.g., sucrose, amino acids, alkaloids). Specialized epithelial cells, called taste receptor cells (TRCs), expr...

Taste cells in adult mammals are functionally heterogeneous as to the expression of ion channels. How these adult phenotypes are established during postnatal development, however, is not yet clear. We have addressed this issue by studying voltage-gated K(+) and Cl(-) currents (I(K) and I(Cl), respectively) in developing taste cells of the mouse val...

The mammalian vomeronasal organ (VNO) contains specialized neurones that transduce the chemical information related to pheromones into discharge of action potentials to the brain. Molecular and biochemical studies have shown that specific components of the pheromonal transduction systems are segregated into two distinct subsets of vomeronasal neuro...

We investigated whether electrical stimulation (STIM) of efferent vagus nerves may suppress nuclear factor (NF)-kappaB activation and the inflammatory cascade in hemorrhagic (Hem) shock. Rats were subjected to bilateral cervical vagotomy (VGX) or sham surgical procedures. Hem shock was induced by intermittent withdrawing of blood until mean arteria...

The vomeronasal organ (VNO) is a chemosensory structure involved in the detection of pheromones in most mammals. The VNO sensory epithelium contains both neurons and supporting cells. Data suggest that vomeronasal neurons represent the pheromonal transduction sites, whereas scarce information is available on the functional properties of supporting...

Taste buds are sensory end organs that detect chemical substances occurring in foodstuffs and relay the relative information to the brain. The mechanisms by which the chemical stimuli are converted into biological signals represent a central issue in taste research. Our understanding of how taste buds accomplish this operation relies on the detaile...

The mammalian peripheral taste system undergoes functional changes during postnatal development. These changes could reflect age-dependent alterations in the membrane properties of taste cells, which use a vast array of ion channels for transduction mechanisms. Yet, scarce information is available on the membrane events in developing taste cells. W...

Somatostatin (somatotropin release-inhibiting factor, SRIF) receptor subtypes are expressed by several retinal neurons, suggesting that SRIF acts at multiple levels of the retinal circuitry, although functional data on this issue are scarce. Of the SRIF receptors, the sst2A isoform is expressed by rod bipolar cells (RBCs) of the rabbit retina, and...

Sodium ions occurring in food are thought to be detected, at least in part, through specific amiloride-sensitive, sodium channels (ASSCs) localized in taste receptor cells. Cells within taste buds are morphologically heterogeneous, and include taste receptor cells and other cells that could perform a support or even transduction role. It is not kno...

Taste buds are sensory structures made up by tightly packed, specialized epithelial cells called taste cells. Taste cells are functionally heterogeneous, and a large proportion of them fire action potentials during chemotransduction. In view of the narrow intercellular spaces within the taste bud, it is expected that the ionic composition of the ex...

Chemosensory cells in vertebrate taste organs have two obvious specializations: an apical membrane with access to the tastants occurring in food, and synapses with sensory axons. In many species, however, certain differentiated taste cells have access to the tastants but lack any synaptic contacts with axons, and a supportive rather than chemosenso...

We studied taste transduction in sensory receptor cells. Specifically, we examined the actions of glutamate, a significant taste stimulus, on the membrane properties of taste cells by applying whole cell patch-clamp techniques to cells in rat taste buds isolated from foliate and vallate papillae. In 55 of 91 taste cells, bath-applied glutamate, at...

1. Whole cell patch-clamp recordings and electron micrographs were obtained from cells in Necturus taste buds in lingual slices to study their membrane properties and to correlate these properties with cell ultrastructure. 2. Two different populations of taste receptor cells could be identified: one type possessed voltage-gated Na+ and K+ (noninact...