Biomedical subjects

M E Frank

Publications and source records attributed to M E Frank.

At least 37 records · Page 2Linked to original sources

PubMed1996

Analysis of polysaccharide taste in hamsters: behavioral and neural studies.

A series of studies was carried out in hamsters (Mesocricetus auratus) to determine whether polysaccharides have behavioral and neurophysiological characteristics that distinguish them from simple sugars. Behavioral studies utilized solutions of glucose, maltose, sucrose, Polycose, and glycogen in two-bottle preference tests and in tests of generalization of conditioned taste aversions. Multiunit and single-unit responses of the chorda tympani nerve were studied with the same stimuli. Neural responses to Polycose and glycogen were found to be generated primarily by ionic contaminants. Dialysis or deionization dramatically reduced electrophysiological responses, a result consistent with occurrence of Polycose and glycogen sensitivity in electrolyte-sensitive nerve fibers. Effects of treatment with the Na + -channel blocker amiloride and cross-adaptation were also consistent with neural responses generated by ionic contaminants. Hamsters showed strong preferences for the sugars and Polycose, a mixture of glucose polymers with alpha-1,4 linkages, and even stronger preferences for a glycogen preparation. Conditioned flavor aversions were established to glycogen, sucrose, and maltose, but no aversion was learned to 3.2% Polycose. The learned aversion to maltose partly generalized to glycogen and sucrose, but sucrose and glycogen did not cross-generalize. Deionization did not affect the preferences for Polycose and glycogen but removal of contaminants of mol.wt. < or = 7000 Da greatly reduced preference for glycogen. In conclusion, glycogen itself, after removal of low molecular weight contaminants, is a poor taste stimulus in hamsters, both behaviorally and neurophysiologically. However, Polycose is highly preferred by hamsters but gives little chorda tympani response after removal of ionic contaminants. In alert animals, the action of salivary amylase on polysaccharides may produce simpler, detectable taste stimuli.

Amiloride↗

PubMed1996

Are the tastes of polycose and monosodium glutamate unique?

To study whether Polycose and monosodium L-glutamate (L-MSG) have unique tastes differing from the traditional four basic tastes, chemosensory profiles were established for Polycose, L-MSG and a group of related compounds (sucrose, maltose, monosodium D-glutamate (D-MSG), sodium chloride, calcium chloride). Flavors were assessed using whole-mouth tests in human subjects with nose open or clamped to reduce olfactory input. Polycose (a mixture of glucose-based oligosaccharides) had a flavor consisting of an olfactory component and a maltose-like taste. L-MSG and D-MSG profiles differed from each other, and from NaCl and CaCl2. L-MSG had a lower threshold and a higher frequency of 'other' tastes than the D form. The data do not support a 'polysaccharide' taste, but suggest a chiral receptor site for 'umami' taste.

Adult↗

PubMed1996

Effects of chorda tympani transection on long-term salt preference in hamsters.

The effects of denervation of fungiform taste buds on preference behavior were studied. Presurgery, 0.01, 0.1, 0.2, and 0.4 M NaCl, and 0.1, 0.2, and 0.4 M KCl were strongly avoided relative to water as measured with 48-h intakes. Bilateral cuts of the chorda tympani nerve (CT) resulted in a decrease in the strength of aversions to all concentrations of NaCl and to 0.2 and 0.4 M KCl. Only 0.4 M NaCl and KCl were strongly avoided after CT section. After CT section, when the animals were allowed to choose between equimolar (0.1 or 0.2 M) KCl and NaCl, they drank equal amounts, whereas intact hamsters preferred KCl to NaCl. In golden hamsters, unlike most laboratory rat strains, intake-based long-term preference behavior for salts is significantly affected by selective gustatory deafferentation.

Animals↗

PubMed1995

Effects of chlorhexidine on human taste perception.

Chlorhexidine gluconate at a dose used to control bacteria in the mouth has a reversible effect on taste perception. Taste-intensity ratings and taste-quality identification for concentration series of sucrose, sodium chloride, citric acid and quinine hydrochloride were obtained from 15 healthy humans. The participants rinsed with 0.12% chlorhexidine for 3 min twice a day. Each individual was tested 3 times: before the 4-day rinse period, 30 min after the final rinse, and 4 days after the rinse period. Chlorhexidine rinses reduced the perceptual intensity of sodium chloride and quinine hydrochloride, not sucrose or citric acid. No effects on taste perception were detected 4 days after the rinse period. The identification of sodium chloride as salty was seriously impaired by chlorhexidine but the identification of quinine hydrochloride as bitter was not affected. Specific sites of action of chlorhexidine on the taste epithelium are not known but its effects on salty taste may be related to its strong positive charge and its effect on bitter taste may be related to its amphiphilicity. Chlorhexidine has promise as a probe of taste transduction, as well as for the management of salty/bitter dysgeusias in humans.

Adult↗

PubMed1995

Visualizing taste papillae in vivo with scanning electron microscopy of a high resolution cast.

A method using polyvinylsiloxane (PVS), a high-resolution dental impression material, to obtain negative images of lingual surfaces is described. Epoxy-resin tongue replicas made from these impressions were examined with scanning electron microscopy (SEM). This method has been developed to visualize structural details of the tongue surface of living human beings and laboratory animals. The utility of the method is demonstrated with hamster tongues, which have well-defined fungiform papillae with single taste pores, and human tongues, which have more variable surface structures. Replicas made from PVS impressions of tongues of living hamsters were compared with the same tongues after fixation. The replicas contained much of the detail present in fixed tongues. With SEM, it was possible to identify individual fungiform papillae, which contained depressions with the size and the location of hamster taste pores. Individual papillae could also be recognized in human-tongue replicas, but taste pores could not be identified with certainty. These replicas provide permanent, three-dimensional records of tongue topography that could be used to document changes due to trauma, disease and aging.

Animals↗

PubMed1995

Allergic rhinitis and olfactory loss.

BACKGROUND: Allergic rhinitis is associated with reports of olfactory loss, but there are few formal investigations. Patients with diminished smell function frequently have nasal polyps or sinusitis, making it difficult to separate the impact of allergic rhinitis from the effects of these other problems. OBJECTIVE: The goals of this descriptive study were to establish the prevalence of positive skin tests in patients reporting rhinitis and olfactory deficiency, and to assess olfactory function and the results of skin testing in a patient group with chronic rhinitis but without concomitant sinusitis or nasal polyps. METHODS: Sixty-two patients reporting olfactory loss and chronic rhinitis were examined by history, physical examination, olfactory testing, skin testing with perennial and seasonal allergens, endoscopic rhinoscopy, and CT scan of the paranasal sinuses. RESULTS: Seventy-one percent of all the subjects had at least one positive skin test, 69% to a perennial allergen, and 58% to mite. Eighty-two percent of the 28 subjects with chronic rhinitis but no evidence of polyps or sinusitis had positive tests. The mean olfactory score for this rhinitis group was 4.35, consistent with moderate hyposmia. The mean olfactory score of 34 subjects with polyps and/or chronic sinusitis was 0.61, consistent with anosmia, and significantly lower (P < .001). Sixty-two percent of this group had positive skin tests. CONCLUSION: These subjects who experienced olfactory loss and rhinitis appeared to have a high prevalence of allergic rhinitis as suggested by the number of positive skin tests. Olfactory loss was observed in patients without polyps or sinusitis, which suggests that allergic processes may have affected olfactory function.

Adolescent↗

PubMed1993

Morphological types of neurons located at taste-responsive sites in the solitary nucleus of the hamster.

HRP histochemistry and microelectrode mapping were combined to study the sizes, shapes, and orientations of neuronal cell bodies and dendrites located at sites of taste-elicited single unit activity in the nucleus of the solitary tract (NST). Cells responding to sapid stimulation of the anterior tongue were extracellularly recorded using micropipettes containing HRP. Iontophoretic injection of the marker at the recording sites resulted in small (50-200 microns diameter) opaque zones bordered by a small number (2-15) of neurons with Golgi-like filling of their cell bodies, dendrites, and to some extent, their axons. The cell bodies were near (50-250 microns) the injection sites into which they sent labelled dendrites. Two broad categories of neurons were typically filled. Elongate cells had oval- to spindle-shaped cell bodies oriented mediolaterally. Two primary dendrites extended 100-300 microns from the cell body, one medially and one laterally, and branched within a cylindrical dendritic field oriented mediolaterally. A minority of the HRP-filled elongate cells had unusually long rostrally or caudally directed dendritic branches. Stellate cells had oval, round, triangular, or polygonal cell bodies and 3-5 primary dendrites coursing 200-300 microns in all directions and branching as unoriented, spheroidal fields. A minority of stellate cells had relatively unbranched wavy dendrites, resembling tentacles, while others had unusually small cell bodies (10-15 microns diameter), small dendrites, and locally arborizing axons. Of 151 labelled cells, all but 12 were remarkably confined to the rostral NST. Nearly 90% were concentrated in the rostral central cytoarchitectonic subdivision, where stellate cells predominated, or in the rostral lateral subdivision, where elongate cells predominated. These morphological types of neurons, filled at neurophysiological recording sites, are compared with cell types identified in previous light and electron microscopic studies of the cytoarchitecture, connections, and synaptic organization of the gustatory NST.

Animals↗

PubMed1993

Loss and recovery of sodium-salt taste following bilateral chorda tympani nerve crush.

The ability of the gustatory system to recover following peripheral nerve injury was investigated in adult hamsters. A conditioned taste aversion paradigm was utilized to test sodium salt-taste function after bilateral crush of the chorda tympani nerve and after nerve regeneration. Bilateral chorda tympani crush abolished expression of a previously learned conditioned taste aversion to 0.1 M NaCl. At 10 to 16 weeks following surgery, the hamsters were reconditioned three times to 0.1 M NaCl. The hamsters were able to relearn the conditioned taste aversion and by 16 weeks, the crush and sham groups showed equally strong and specific aversions to 0.1 M NaCl. A second surgery to cut the regenerated chorda tympani nerves resulted, again, in the loss of expression of the conditioned taste aversion. Thus, regenerated chorda tympani nerves are capable of carrying the information needed to form a conditioned taste aversion specific for sodium salts in the adult hamster.

Animals↗

PubMed1993

Anion modulation of taste responses in sodium-sensitive neurons of the hamster chorda tympani nerve.

Beidler's work in the 1950s showed that anions can strongly influence gustatory responses to sodium salts. We have demonstrated "anion inhibition" in the hamster by showing that the chorda tympani nerve responds more strongly to NaCl than to Na acetate over a wide range of concentrations. Iontophoretic presentation of Cl- and acetate to the anterior tongue elicited no response in the chorda tympani, suggesting that these anions are not directly stimulatory. Drugs (0.01, 1.0, and 100 microM anthracene-9-carboxylate, diphenylamine-2-carboxylate, 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonate, and furosemide) that interfere with movements of Cl- across epithelial cells were ineffective in altering chorda tympani responses to 0.03 M of either NaCl or Na acetate. Anion inhibition related to movements of anions across epithelial membranes therefore seems unlikely. The chorda tympani contains a population of nerve fibers highly selective for Na+ (N fibers) and another population sensitive to Na+ as well as other salts and acids (H fibers). We found that N fibers respond similarly to NaCl and Na acetate, with spiking activity increasing with increasing stimulus concentration (0.01-1.0 M). H fibers, however, respond more strongly to NaCl than to Na acetate. Furthermore, H fibers increase spiking with increases in NaCl concentration, but generally decrease their responses to increasing concentrations of Na acetate. It appears that anion inhibition applies to taste cells innervated by H fibers but not by N fibers. Taste cells innervated by N fibers use an apical Na+ channel, whereas those innervated by H fibers may use a paracellularly mediated, basolateral site of excitation.

Acetates↗

PubMed1992

Organization of taste-evoked activity in the hamster parabrachial nucleus.

Small groups of 3-4 neighboring taste neurons in the hamster parabrachial nucleus (PBN) were either generalists (42%) or specialists (58%). Generalists responded well to sucrose, NaCl, KCl, and their mixture but specialists responded to only one or two stimuli. PBN temporal response patterns resembled chorda tympani patterns, indicating that they were preserved across two synapses. Generalist neuron-groups were distributed throughout the central medial (CM) subdivision of PBN. Sucrose-sensitive neuron-groups, which responded best to mixtures, were restricted to rostral CM, whereas most NaCl-best neuron groups were in caudal CM. These results suggest a multifaceted functional organization of taste sensibilities in the PBN.

Animals↗

PubMed1992

Response of the gustatory system to peripheral nerve injury.

Peripheral taste nerve damage occurs as a result of disease and surgery. The response depends on the taste field affected and the species. Nerve regeneration is robust after the nerve is crushed or after it is cut if the severed ends are anastomosed. Taste buds, which appear after nerve regeneration, may be derived from dormant stem cells outside of taste buds or from remnants of taste buds that persist following denervation. Sprouting by intact taste nerves into denervated fields apparently does not occur. Regenerated primary afferents have taste response specificity, but it is unknown if neural response types are retained peripherally or centrally. Recent behavioral studies show specific deficits following loss of restricted taste fields in rodents, but little is known about recovery after nerve regeneration. Specific deficits have not been demonstrated in humans, although taste sensitivity has been correlated with numbers of taste buds. Enigmas such as these may be solved once the response of the central nervous system to gustatory nerve injury is defined.

Animals↗

PubMed1992

Information processing in mammalian gustatory systems.

The taste system has multiple functions that are carried by three cranial nerves. It is now apparent that these functions cannot be accommodated by a single coding mechanism for taste quality. A current view emphasizes the likely existence of coding channels activated by specific sets of receptors.

Animals↗

PubMed1992

The sense of taste: neurobiology, aging, and medication effects.

The sense of taste is an oral chemical sense in mammals that is involved in the choice of foods. Initial transduction of taste stimuli occurs in taste buds, which are distributed in four discrete fields in the oral cavity. Medications can affect the taste buds and ion channels in taste-bud cell membranes involved in stimulus transduction. The sense of taste gradually declines with aging, with bitter taste most affected. Neural circuits that mediate taste in primates include cranial nerves VII, IX, and X, the solitary nucleus in the brain stem, the ventroposteromedial nucleus of the thalamus, and the insular-opercular cortex. The central taste pathways process taste information about sweet, salty, sour, and bitter stimuli serially and in parallel. Medications associated with "metallic" dysgeusia and taste losses affect the taste system via unknown mechanisms.

Aging↗

PubMed1991

Mapping study of the parabrachial taste-responsive area for the anterior tongue in the golden hamster.

The locations of taste-responsive areas within the brainstem parabrachial nucleus (PBN), an obligatory taste relay in the golden hamster (Mesocricetus auratus), were mapped in relation to cytoarchitectural boundaries. The PBN was systematically searched for multiunit neural activity in response to a taste mixture composed of 0.1 M sucrose, 0.03 M NaCl, and 0.1 M KCl applied to the anterior tongue. Taste responses were located exclusively in one of three subdivisions of the medial PBN, which is thought to be specialized for gustatory processing, and in one of six subdivisions of the lateral PBN, which is thought to be specialized for general visceral processing. Based on Nissl-stained material, both the medial and lateral PBN subdivisions in the hamster were similar to those reported for the rat PBN. The largest group of taste-responsive cells encompassed two-thirds of the central medial subdivision, while a smaller group of taste cells was exclusively located within the ventral lateral subdivision. The two taste-responsive subdivisions are separated by the superior cerebellar peduncle and contain diverse cell types. The finding that anterior tongue taste may be exclusively represented in circumscribed cytoarchitecturally defined parts of two PBN divisions suggests that taste information from the anterior tongue is required for both specific gustatory and general visceral functions.

Animals↗

PubMed1991

Taste-responsive neurons of the glossopharyngeal nerve of the rat.

1. Taste sensibilities of neurons in mammalian glossopharyngeal nerves have been inadequately studied, although they innervate the majority of taste buds and may provide unique taste information. 2. Extracellular responses of glossopharyngeal neural units to taste stimuli infused into foliate or vallate papillae were recorded in anesthetized rats. A 0.3-ml/min infusion of stimuli into papillae resulted in short-latency, 5-s nerve-impulse rates that approached 10 times the response rates observed using less invasive means of stimulation. 3. Sucrose, Na saccharin, NaCl, NH4Cl, KCl, HCl, citric acid, acetic acid, MgSO4, and quinine.HCl were effective stimuli for glossopharyngeal neurons at concentrations that have behavioral significance. 4. Response spectra for individual neural units with either foliate or vallate receptive fields fell into three clusters. Forty-six percent were A units that responded most strongly to acids and chloride salts, NH4Cl being the most effective; neither quinine nor sucrose was effective. Twenty-three percent were S units that responded to sugars and saccharin; quinine, salts, and acids were not effective. Thirty-one percent were Q units that responded to quinine; neither NaCl, HCl, nor sucrose was effective stimulus for these fragile units. 5. Glossopharyngeal A neural units were more sensitive to 1 mM HCl than were electrolyte-sensitive H units of the chorda tympani, although both respond generally to salts and acids. Units relatively specific for sodium salts (N units), which are common in the chorda tympani nerve, were not found in the glossopharyngeal nerve, which explains losses in sodium-specific behavior after cutting only the chorda tympani nerve. 6. Q units were the only glossopharyngeal neural units that responded significantly to quinine, and units with similar response spectra do not occur in the chorda tympani nerve. Q units probably mediate aversive reflexes to quinine that are eliminated by cutting only the glossopharyngeal nerve. Glossopharyngeal S neural units were more sensitive to sucrose and are more common than their counterparts in the chorda tympani, although it is not known how they might compare with sugar-sensitive units in the greater superficial petrosal nerve. 7. These data strongly suggest that posterior taste bud fields innervated by the glossopharyngeal nerve are specialized for functions different from those of anterior taste bud fields innervated by the facial nerve.

Animals↗

PubMed1991

Transition into midlife.

During the midlife years, ages 35 through 65 years, women experience a series of transitions. How the transitions affect the midlife woman depends, in part, on her vision of those transitions and her strategy for dealing with them. This chapter provides a framework for understanding the transition process. In addition, it provides strategies for attenuating the psychological, physiologic, and social changes that often result with the transition into midlife.

Adaptation, Psychological↗

PubMed1990

Specificity of amiloride inhibition of hamster taste responses.

Amiloride, a blocker of epithelial sodium channels, was found to have significant effects on electrophysiological and behavioral taste responses in the golden hamster (Mesocricetus auratus). Recordings from the whole chorda tympani nerve showed that amiloride rapidly, reversibly, and competitively inhibited responses to NaCl applied to the anterior tongue. The apparent dissociation constant for amiloride binding, extrapolated to zero NaCl concentration, was 10 nM, a value comparable to estimates for various transporting tight epithelia. Recordings from single chorda tympani nerve fibers showed that 10 microM amiloride completely inhibited responses of Na-selective N fibers but had minimal effect on responses of electrolyte-sensitive H fibers, even though both types of fibers responded well to 0.1 M NaCl. Sucrose responses were not affected by amiloride. Addition of 100 microM amiloride to 0.1 M NaCl consistently increased consumption of NaCl in two-bottle drinking tests. These data suggest that one mechanism by which the taste of NaCl is sensed, which does not require adsorption or a second messenger, involves entry of Na+ into taste bud cells through an amiloride-blockable sodium channel. Taste bud cells utilizing this mechanism exclusively activate N fibers, which are involved in the control of NaCl intake. A different mechanism for the detection of NaCl and other electrolytes is utilized by taste bud cells that activate H fibers.

Action Potentials↗

PubMed1990

The role of sucrose-sensitive neurons in ingestion of sweet stimuli by hamsters.

The relationship between sweet preference and activity in sucrose-sensitive chorda tympani nerve fibers was investigated in hamsters (Mesocricetus auratus). Without exception, hamsters increased consumption of aqueous solutions of nonsweet 0.1 M NaCl, 0.001 M quinine-HCl, 0.01 M citric acid, 0.001 M dithiothreitol, 0.01 M pyridine, 0.01 M 2-phenylethanol, 0.005 M i-amyl acetate, 0.01 M vanillin, half-saturated 1-menthol and 0.033 mM capsaicin if they were made sweet by adding 0.5 M sucrose. Since sucrose activates chorda tympani S fibers, activity in these nerve fibers may be sufficient for increased preference. To determine if S-fiber activity is necessary for preference, equally preferred sweet stimuli were presented to the tongue while recording responses of single chorda tympani fibers. S fibers were clearly activated by 0.03 M sucrose, 0.001 M Na saccharin, 0.01 M D-phenylalanine, 0.1 M glycine, 0.005 M dulcin and 0.03 M Na 2-mercaptoethanesulfonate but not by 0.01 M Ca cyclamate and 0.003 M Na 3-nitrobenzenesulfonate. Ca cyclamate weakly activated H fibers and Na 3-nitrobenzenesulfonate weakly activated N fibers. Thus, S-fiber chorda tympani activity may be sufficient but not necessary for sweet preference, which may be influenced by activity in fibers of other taste nerves.

Animals↗