Role In Sensory Perception Research Articles

Subunit‐dependent cadmium and nickel inhibition of acid‐sensing ion channels

Acid-sensing ion channels (ASIC) are ligand-gated cation channels that are highly expressed in peripheral sensory and central neurons. ASIC are transiently activated by decreases in extracellular pH and are thought to play important roles in sensory perception, neuronal transmission, and excitability, and in the pathology of neurological conditions, such as brain ischemia. We demonstrate here that the heavy metals Ni(2+) and Cd(2+) dose-dependently inhibit ASIC currents in hippocampus CA1 neurons and in Chinese hamster ovary (CHO) cells heterologously expressing these channels. The effects of both Ni(2+) and Cd(2+) were voltage-independent, fast, and reversible. Neither metal affected activation and desensitization kinetics but rather decreased pH-sensitivity. Moreover, distinct ASIC isoforms were differentially inhibited by Ni(2+) and Cd(2+). External application of 1 mM Ni(2+) rapidly inhibited homomeric ASIC1a and heteromeric ASIC1a/2a channels without affecting ASIC1b, 2a, and ASIC3 homomeric channels and ASIC1a/3 and 2a/3 heteromeric channels. In contrast, external Cd(+) (1 mM) inhibited ASIC2a and ASIC3 homomeric channels and ASIC1a/2a, 1a/3, and 2a/3 heteromeric channels but not ASIC1a homomeric channels. The acid-sensing current in isolated rat hippocampus CA1 neurons, thought to be carried primarily by ASIC1a and 1a/2a, was inhibited by 1 mM Ni(2+). The current study identifies ASIC as a novel target for the neurotoxic heavy metals Cd(2+) and Ni(2+).

The role of sensory perception in the development and targeting of tobacco products

To examine tobacco industry research on smoking-related sensory effects, including differences in sensory perception across smoker groups, and to determine whether this research informed targeted product development and impacted the development of commercial tobacco products. We searched previously secret internal tobacco industry documents available online through document databases housed at Tobacco Documents Online, the British American Tobacco Document Archive and the Legacy Tobacco Documents Library. We identified relevant documents using a snowball sampling method to first search the databases using an initial set of key words and to then establish further search terms. Sensory research is a priority within the tobacco industry directly impacting commercial markets both in the United States and internationally. Sensory factors contribute to smoker satisfaction and product acceptance, and play an important role in controlling puffing behavior. Cigarette manufacturers have capitalized on distinct sensory preferences across gender, age and ethnic groups by tailoring products for specific populations. Regulation of tobacco products is needed to address product changes that are used to reinforce or contribute to tobacco dependence; for instance, the incorporation of additives that target attributes such as smoothness, harshness and aftertaste. Greater understanding of the role of sensory effects on smoking behavior may also help to inform the development of tobacco treatment options that support long-term tobacco abstinence.

“Supporting” Players Take the Lead in Protecting the Overstimulated Brain

For many years, astrocytes got no respect. These star-shaped cells were long considered mere space fillers, providing structural support to buttress their betters. It’s now clear that astrocytes play an active role in brain function. With their octopus-like protrusions, called processes, astrocytes remove neurotransmitters from neuron synapses, regulate the chemical composition of the extracellular environment, and can influence neuronal activity. And now a new study by Christel Genoud, Graham Knott, and colleagues provides further evidence that astrocytes take a proactive role in brain function, by showing that alterations in cortical activity cause changes in the physical interactions between astrocytes and neurons. These changes could facilitate the uptake of potentially damaging excess neurotransmitters. Brain signals travel down the axon of a transmitting, or “presynaptic,” neuron as an electrical impulse. The electrical signal is converted into a chemical signal (neurotransmitter) when the impulse reaches the presynaptic nerve terminal (or bouton). Neurotransmitters carry the signal across the gap between neurons, called the synaptic cleft, to a dendrite of the receiving, “postsynaptic” neuron. Interactions between the bouton and specialized postsynaptic protrusions in dendrites, called dendritic spines, mediate synaptic transmission. Clearing glutamate from the synaptic cleft may be astrocytes’ most critical function. The principal neurotransmitter in the brain, glutamate plays a major role in sensory perception. But too much glutamate causes trouble: as an excitatory neurotransmitter, it can stimulate the postsynaptic neuron until it is reabsorbed by membrane-bound transporters in the transmitting neuron or by transporters in astrocytes. Overstimulation can damage the nervous system, causing seizures and even stroke. Astrocytes take up glutamate with two transporters—glutamate transporter 1 (GLT1) and glutamate aspartate transporter (GLAST)—and corral excess glutamate with their abundant processes. (Neuronal transporters recycle neurotransmitters for later use.) Genoud et al. wondered whether increased neuronal activity in the sensory cortex would trigger a corresponding response in astrocytes. To find out, the authors hyperstimulated a single whisker in unanesthetized adult mice, a protocol that triggers physiological and morphological changes in the region of the sensory cortex that receives information from the stimulated whisker. Adult mice received 24 hours of continuous whisker stimulation The authors then located and removed the corresponding region of the cortex. Tissue was extracted immediately after stimulation from one group and four days later from another stimulated group. After 24 hours of whisker stimulation, levels of both astrocyte glutamate transporters, GLT1 and GLAST, more than doubled. Four days after stimulation had stopped, transporter levels returned to those seen in the unstimulated controls. The researchers also analyzed levels of the neuronal glutamate transporter EAAC1 in a separate group of animals but found that stimulation had little effect on its expression. Using electron microscopy and serial sections of the stimulated brain samples, the authors used high-resolution images to generate 3D reconstructions of the contacts between astrocytes and adjacent bouton-dendritic spine pairs. These reconstructions showed that stimulation caused a marked increase in the percentage of spines with their excitatory synapses “completely occupied” by astrocytes. Although stimulation does not increase contact between dendritic spine and bouton, it does rouse astrocytes to encircle the interacting synapses, where glutamate is transmitted. Both stimulation-triggered changes in astrocyte shape and behavior—glomming onto excitatory synapses and upregulating their glutamate transporters—help clear glutamate from the synaptic cleft. Through flexible, dynamic interactions with neurons, the authors conclude, astrocytes prevent the accumulation of glutamate, which is most likely to occur during sensory overstimulation. This study demonstrates yet another functional benefit of astrocyte-neuron interactions, but the authors expect to find more. Given astrocytes’ control over synaptic transmission and evidence that they can release their own neurotransmitters, it seems these long-misunderstood cells are finally getting their just desserts.

The neurophysiology of osseointegrated oral implants. A clinically underestimated aspect

Amputation of a limb or a tooth leads to the loss of a large number of exteroceptors. These play an important role in sensory perception and feedback, which tune the motor control. Even after rehabilitation with a prosthetic device, tactile function remains impaired. This can present a subsequent risk of overloading the prosthesis. The peri-implant interface of oral osseointegrated implants is characterized by the absence of a periodontal ligament, a crucial difference towards the natural dentition, from a biomechanical but also from a neurophysiologic point of view. Patients rehabilitated with osseointegrated implants seem subjectively not much impaired in their masticatory and other oral functions. This observation might be linked to the presence of some peripheral feedback pathway to the sensory cortex. It may be attributed to the activation of receptors in the peri-implant environment (either bone or periosteum). This phenomenon called osseoperception, when it relates to the consciousness of the applied stimuli, has been described for both oral and skeletal implants. In the present review, besides osseoperecption other neurophysiological aspects of oral implants, such their reflex function, will be outlined and their clinical meaning pointed out.

Presence of gular and parietal pits in Atretium schistosum (Serpentes, Colubridae), a singular trait not exclusive to psammophine snakes

The sporadic occurrence of localised pits on parietal plates was recently discovered in different colubrid genera of the subfamily Psammophiinae; these were considered to play a role in sensory perception. In the present study, we describe the presence of similar structures in Atretium schistosum, another colubrid snake reportedly not belonging to the Psammophiinae. As this species is suspected of being phylogenetically distantly related to psammophine snakes, some hypotheses are provided to explain (1) the putative function of these pits, (2) their sporadic occurrence, and (3) to suggest when they may have evolved in the colubroid snake clade. To cite this article: A. Miralles, I. Ineich, C. R. Biologies 329 (2006).

Fatty Acid Profiles and Sensory Properties of Longissimus dorsi, Triceps brachii, and Semimembranosus Muscles from Korean Hanwoo and Australian Angus Beef

The study compared the fatty acid profiles of 3 muscles (Longissimus dorsi, LD, Triceps brachii, TB and Semimembranosus, SM) obtained from Korean Hanwoo (18 steers, 24 months old) and Australian Angus beef (18 steers, 24 months old) and assessed their role in sensory perception. The samples of each carcass were prepared in the same manner, and cooked both as traditional grilled steaks and Korean BBQ style. A total of 720 Korean sensory panelists evaluated the beef samples for tenderness, juiciness, flavor, and overall liking. Oleic acid (18:1) was significantly (p<0.05) higher in TB than that in LD and SM. The essential linoleic acid (C18:2) was significantly (p<0.05) higher in TB and SM than that in LD. For LD muscle, the proportion of saturated fatty acids was significantly (p<0.05) highest, while that of polyunsaturated fatty acids was lowest among the three muscles. Australian Angus beef had significantly (p<0.05) higher n-3 PUFA than that of the Korean Hanwoo for the three muscles, while the latter contained significantly (p<0.05) higher n-6 PUFA than that of the former. The clustering analysis showed that there a was significant difference in fatty acids such as C16:0, C16:1n7, C18:0, C18:2n6, C18:3n3, C20:3n6, C20:4n6, C22:4n6, and C22:5n3 for sensory perception (tenderness, juiciness, flavor and overall likeness) of the beef from two origins (p<0.05) among three clusters. Especially, C14:0 had a significant effect on sensory perception only for Korean Hanwoo beef; while C20:5n3 had a significant (p<0.05) effect only for Australian Angus beef based on clustering with the sensory variables. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 12 : 1786-1793)

Drosophila regulatory factor X is necessary for ciliated sensory neuron differentiation.

Ciliated neurons play an important role in sensory perception in many animals. Modified cilia at dendrite endings serve as sites of sensory signal capture and transduction. We describe Drosophila mutations that affect the transcription factor RFX and genetic rescue experiments that demonstrate its central role in sensory cilium differentiation. Rfx mutant flies show defects in chemosensory and mechanosensory behaviors but have normal phototaxis, consistent with Rfx expression in ciliated sensory neurons and neuronal precursors but not in photoreceptors. The mutant behavioral phenotypes are correlated with abnormal function and structure of neuronal cilia, as shown by the loss of sensory transduction and by defects in ciliary morphology and ultrastructure. These results identify Rfx as an essential regulator of ciliated sensory neuron differentiation in Drosophila.

New Approaches for the Determination of Ventilation Rates: The Role of Sensory Perception

This paper evaluates the use of sensory perception in defining indoor air qual ity and, in particular, in assessing appropriate ventilation rates for European office buildings. It is suggested that there is too little known about the odour pollution arising from building materials to use sensory perception alone to predict what ventilation systems and ventilation rates should be designed into a building to provide both health and comfort. Examples are given where the use of the olf unit could give quite misleading predictions. The ASHRAE 62- 1989 standard for defining ventilation rates in buildings is suggested as a prag matic, sensible and practical existing alternative.

New Approaches for the Determination of Ventilation Rates: The Role of Sensory Perception

This paper evaluates the use of sensory perception in defining indoor air quality and, in particular, in assessing appropriate ventilation rates for European office buildings. It is suggested that there is too little known about the odour pollution arising from building materials to use sensory perception alone to predict what ventilation systems and ventilation rates should be designed into a building to provide both health and comfort. Examples are given where the use of the olf unit could give quite misleading predictions. The ASHRAE 62- 1989 standard for defining ventilation rates in buildings is suggested as a pragmatic, sensible and practical existing alternative.

The Vanishing Subject: Early Psychology and Literary Modernism (review)

Reviewed by: The Vanishing Subject: Early Psychology and Literary Modernism Alan Wilde Judith Ryan . The Vanishing Subject: Early Psychology and Literary Modernism. Chicago: U of Chicago P, 1991. x + 267 pp. $29.95. In the current critical climate, Judith Ryan's examination of modernism is bound to seem somewhat old-fashioned. Untouched by the confusing crosswinds of postmodernism or by more recent gusts from the direction of New Historical studies, The Vanishing Subject honors both clarity and discrimination. Determined not to leap to conclusions or to indulge in premature generalization, it seeks precision above all. Ryan's statement of purpose—"to rediscover a lost element in the genesis of modernism, not to construct a theory about the period as a whole"—suggests her tone and methodology as well as her project. It has to be said, however, that the modesty with which she conducts her investigation underplays the excitement of what she has discovered. The "lost element" she refers to is empiricist psychology as illustrated in the works of Brentano, Mach, and William James, although its relation to the literary empiricism of the years 1880-1940, her major concern, has to do, as she repeatedly insists, not with simple "influence" but with "complex intertextuality." [End Page 427] Empiricist psychology, as Ryan defines it early on, "meant that the only admissible evidence for the existence of something was that of our senses; the only reality was that of our consciousness"—both of which beliefs lead, in turn, to the rejection of metaphysics and dualism. Although one of the four sections that house her fifteen writers deals specifically with "authors who took issue with empiricism and sought new ways of consolidating the self," Ryan points out in her conclusion that "few of the authors actually agreed with the new psychologies" and that "there is scarcely an author who is not deeply disturbed by the conflict between empiricism and more familiar modes of thought." Not surprisingly, given the sometimes tortuous refinements that underlie her discussions of such subjects as "the role of sensory perception in the constitution of the self" and "attempts to revalorize the empiricist vision and develop a new kind of mysticism," and given too the ambivalences that her conclusion acknowledges, there is a good deal of to-ing and fro-ing in The Vanishing Self, and readers are advised to keep their eye on the larger picture. Those who do are likely to find persuasive (and even moving) Ryan's portraits of writers reacting to "the sense of dissolution and fragmentation" to which "the new psychologies" gave rise. Nevertheless, convincing though she may be in her general argument, Ryan's method has its drawbacks. As literary hostess, she offers a buffet that is more various than bountiful, a kind of critical cuisine minceur. Certainly, the range is impressive as we are invited to focus in turn on, among others, Pater, Huysmans, Rilke, Alice and Henry James, Stein, Kafka, Schnitzler, Broch, Proust, and Musil; but as they are served up, one after another, in their smallish chapters, the helping seems just a bit on the skimpy side. Ungratefully, perhaps, one wants more—wants not only the cogent and perceptive demonstrations of how all the writers relate to empiricist psychology (and validate Ryan's thesis) but further, detailed illumination of their writings as these come into new focus under the empiricist lens. (One can argue about particulars too, about Joyce's inclusion, for example, or about the fact that the chapter on Woolf underplays her concern with depth—especially in the discussion of Jacob's Room —and, more generally, her belief in a persisting core of being.) Ryan's scholarly, rhetorically low-keyed, punctilious handling of her topic leads her at the last and "on balance" to reject the notion of "the literature inspired by empiricism as a movement in its own right." And it keeps her as well from mapping out those more recently settled territories in which the embattled self threatens finally (or yet again) to enact its long-threatened disintegration. The "Freudian solution," as the best known of "a number of concerted attempts to consolidate the self," stands as the book's terminus ad quem, and The Vanishing Self...

Ultrastructural studies of the elytra ofPholoe minuta(Annelida: Polychaeta) with special reference to functional morphology

It has been suggested by Pettibone (1953) and Lwebuga-Musaka (1970) that the elytra of scaleworms may function in respiration, not as the sites of gaseous exchange, but rather the means by which respiratory water currents were created over the dorsum. A role in sensory perception was also postulated (Pettibone, 1953). However, no detailed morphological study accompanied this work. To date the scales of only a few polychaete species have been examined ultrastructurally, and these studies have focused mostly on cuticular features (Anton-Erxleben, 1977, 1981a, b). Considerable attention has been focused on the bioluminescent properties of the elytra of the scaleworm,Harmothoe lunulata(Delle Chiaje) (see Bassot, 1979; Nicholaset al.1981, 1982). Other morphological features ofPholoe minutastudied at the ultrastructural level include gametogenic (Heffernan &amp; Keegan, 1988a) and larval (Heffernan &amp; Keegan, 1988b) stages as well as the digestive tract (Heffernan, 1988). There are several reports on the ultrastructure of polychaete gills (Storch &amp; Welsch, 1972; Spies, 1973; Storch &amp; Alberti, 1978; Menendezet al., 1984; Storch &amp; Gaill, 1986). These works have recently been reviewed by Gardiner (1988). This study describes the fine structure of the scales ofPholoe minutaand the features illustrated here are in agreement with a role in respiration and sensory perception.