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1.
Physiol Behav ; 49(5): 1019-24, 1991 May.
Artículo en Inglés | MEDLINE | ID: mdl-1886947

RESUMEN

Studies in the taste system of mammals indicate that monosodium glutamate (MSG) produces a unique taste sensation termed umami. As a derivative of glutamic acid, MSG is a naturally occurring nutrient in many foods; its commercial use to improve food palatability for humans is well documented. Behavioral studies with experimental animals have revealed that preference for MSG in solutions and selection of MSG-flavored diets can be explained by sensory means with no appreciable effects on preference by postingestive consequences. However, preference for umami-flavored fluids is reduced by feeding rats low-protein diets or low quality protein. MSG-flavored diets, initially unpreferred, were subsequently highly selected. However, the adulteration of diets by MSG either did not or only slightly increased food intake. In light of the significant contribution of MSG to diet taste, apparently as a signal coupled to dietary proteins, physiological studies have been initiated to reveal its role as a stimulator of the cephalic phase of pancreatic exocrine secretion. Modified sham-feeding experiments with dogs have shown that oral stimulation by MSG produced significant stimulation of both pancreatic flow and protein output in conscious dogs.


Asunto(s)
Conducta Consumatoria/fisiología , Digestión/fisiología , Preferencias Alimentarias/fisiología , Estado Nutricional/fisiología , Glutamato de Sodio , Gusto/fisiología , Aminoácidos/administración & dosificación , Animales , Nivel de Alerta/fisiología , Reacción de Prevención/fisiología , Proteínas en la Dieta/administración & dosificación , Perros , Masculino , Valor Nutritivo , Jugo Pancreático/fisiología , Ratas , Tasa de Secreción/fisiología , Umbral Gustativo/fisiología
2.
Proc Soc Exp Biol Med ; 195(3): 369-74, 1990 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2175438

RESUMEN

Adenylate cyclase activity was determined in membranes of liver, muscle, white adipose tissue, and brown adipose tissue (BAT) of lean (Fa/) and obese (fa/fa) Zucker rats. Responses were monitored following beta-adrenergic receptor stimulation and addition of GTP, GTP gamma S, or forskolin. beta-Adrenergic responses in liver, white adipose tissue, and BAT were lower in obese than in lean animals. No such difference was observed in muscle membranes. Production of cAMP after addition of guanine nucleotides was lower in liver and white adipose tissue membranes from obese rats compared with their lean littermates. Synthesis of cAMP in muscle membranes of obese animals after addition of GTP was either not different, or slightly higher, than that observed in muscle membranes from lean animals. Furthermore, production of cAMP after forskolin addition to muscle membranes of obese rats was significantly higher than that observed from lean rats under the same conditions. Interestingly, BAT membranes of obese rats were significantly more sensitive to guanine nucleotide activation than those of lean animals. The results confirm recent findings indicating inferior function of G proteins in liver plasma membranes of obese Zucker rats, and extend this observation to adipose tissue. The present results further suggest that the "nonreceptor" components (e.g., G proteins) responsible for the activation of adenylate cyclase in BAT membranes of obese rats are more responsive to stimulation than those of lean animals. Such sensitivity may be related to and perhaps compensate for the reduced thermogenic activity in the obese Zucker rat during the development of obesity.


Asunto(s)
Adenilil Ciclasas/metabolismo , Tejido Adiposo/enzimología , Hígado/enzimología , Músculos/enzimología , Obesidad/enzimología , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo Pardo/efectos de los fármacos , Tejido Adiposo Pardo/enzimología , Animales , Peso Corporal , Colforsina/farmacología , AMP Cíclico/biosíntesis , Relación Dosis-Respuesta a Droga , Femenino , Proteínas de Unión al GTP/fisiología , Guanosina 5'-O-(3-Tiotrifosfato)/farmacología , Guanosina Trifosfato/farmacología , Isoproterenol/farmacología , Hígado/efectos de los fármacos , Músculos/efectos de los fármacos , Norepinefrina/farmacología , Tamaño de los Órganos , Ratas , Ratas Zucker , Receptores Adrenérgicos beta/metabolismo
3.
Am J Clin Nutr ; 51(2): 233-40, 1990 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2305710

RESUMEN

The impact of smell and taste disorders on dietary habits and nutritional status has received limited research attention. This paper reports findings obtained from questionnaires and diet records completed by 40 healthy subjects and 118 patients with chemosensory dysfunction. Chemosensory disorders were frequently associated with decreases in food acceptability. Although dietary responses to these dysfunctions varied greatly, patients with distorted or phantom smell and/or taste sensations tended to report weight loss whereas those with simple sensory loss were more likely to report weight gain. Indices derived from diet records did not indicate that either group of patients was at substantial nutritional risk, but food frequency responses and estimates of body mass index were consistent with patient reports of changes in dietary patterns and weight. In addition, marked weight change and aberrant dietary practices were noted in individual patients. Thus, there were indications that chemosensory dysfunction may be associated with nutritionally important dietary alterations.


Asunto(s)
Ingestión de Alimentos , Estado Nutricional , Trastornos del Olfato , Trastornos del Gusto , Adulto , Peso Corporal , Femenino , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios
4.
Nutr Rev ; 48(2): 39-48; discussion 114-31, 1990 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2407978
6.
J Nutr ; 117(7): 1191-6, 1987 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-3302135

RESUMEN

Stimulation of the oral cavity immediately elicits salivation, gastric acid secretion and pancreatic exocrine and endocrine secretions that serve to prepare the alimentary canal for digestion, transport and utilization of ingested nutrients. Oropharyngeal-stimulated responses are reliably initiated by the taste and smell of food. These gastrointestinal reflexes, often referred to as anticipatory or cephalic phase responses, are mediated by the autonomic nervous system and are believed to be independent of the postabsorptive effects of ingested nutrients. A common pathway used by cephalic phase responses to trigger gastrointestinal secretions is the vagus. Several studies have also demonstrated that cephalic stimulation activates both the sympathetic and parasympathetic nervous systems and thus, many cephalic-metabolic reflexes may arise indirectly from more general physiological changes that accompany oropharyngeal stimulation. The present studies suggest that oral stimulation results in alterations in intestinal function. Specifically, oropharyngeal stimulation of conscious, unrestrained rats with sucrose increases the uptake of radioactive glucose from the small intestine into the hepatic portal blood.


Asunto(s)
Encéfalo/fisiología , Digestión , Metabolismo , Reflejo/fisiología , Animales , Sistema Digestivo/metabolismo , Humanos , Absorción Intestinal , Olfato/fisiología , Gusto/fisiología
7.
Physiol Behav ; 39(3): 285-90, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-3575467

RESUMEN

The preference-aversion behavior of Sprague-Dawley rats for semi-purified diets containing various levels of either corn oil, animal fat (lard) or hydrogenated vegetable oil (Crisco) was determined in brief and long-term, two-choice preference tests. After the first day of exposure, rats selected more calories from the control-unadulterated diet than from experimental diets containing either oil or fat. Only in the first hour of exposure (with diets containing either 5% Crisco, 15 or 25% lard) or in the first day (with diets containing 5% Crisco, 5 or 15% lard) was a preference for experimental diets observed. There were significant effects of oil and fat concentration and of exposure time upon preference for experimental diets, such that preference for the experimental diets was reduced as levels of oil or fat and as the time of experiment increased. Changes in diet selection had no major effect on total caloric intake measured as the sum of both experimental and control dietary choices, although total intake on a daily basis tended to decrease during the middle portion (2-4 days) of the study, then recover by the end of the study. The results suggest that postingestional factors related to the dietary oil and fat (rather than the sensory properties of the diets) directed the long-term preference behavior of rats for semi-purified diets adulterated with various levels of either corn oil, animal fat (lard) or hydrogenated vegetable oil (Crisco).


Asunto(s)
Reacción de Prevención , Grasas de la Dieta , Preferencias Alimentarias , Animales , Ingestión de Energía , Masculino , Ratas , Ratas Endogámicas
8.
Physiol Behav ; 37(1): 15-21, 1986.
Artículo en Inglés | MEDLINE | ID: mdl-3737713

RESUMEN

Preference for nutritionally controlled, semi-purified diets modified by the addition of potent food flavors was determined for Sprague Dawley rats using two-choice diet preference tests. Intake of each food cup was monitored after 1 hr and for each 24 hr period thereafter up to 5 days. Preference was also determined for the flavored diets prepared in three forms differing in texture: powdered, and pellets of two sizes. Rats easily detected minor amounts of the food flavors, and the tests provided a catalog of 12 preferred flavors. Exposure time to the diets altered preference for a minority of flavors; diets initially avoided in the first hour test were likely to become less aversive upon continued exposure. Whether or not a specific flavored diet was preferred, total food intake was not affected during the 5 day period monitored. Rats displayed strong preference for diets of a pelleted texture compared to the same diets in a powdered form.


Asunto(s)
Preferencias Alimentarias , Gusto , Animales , Peso Corporal , Masculino , Ratas , Ratas Endogámicas
9.
Dig Dis ; 4(3): 129-38, 1986.
Artículo en Inglés | MEDLINE | ID: mdl-3545565

RESUMEN

Disorders in different regions of the alimentary tract have been associated with alterations in gustatory function. Current understanding of mechanisms underlying the taste disturbances and their impact on the physical and emotional well-being of patients is incomplete. Indeed, in most instances, present knowledge remains at a descriptive level. Accumulating evidence that profound interactions occur between the sense of taste and alimentary function poses a challenge to apply this knowledge in the clinic setting.


Asunto(s)
Enfermedades Gastrointestinales/complicaciones , Trastornos del Gusto/etiología , Gusto/fisiología , Animales , Enfermedades Gastrointestinales/fisiopatología , Humanos , Trastornos del Gusto/fisiopatología , Trastornos del Gusto/psicología
10.
J Nutr ; 115(11): 1447-58, 1985 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-4056941

RESUMEN

The effect of flavor variety on diet selection, energy intake, weight gain and fat deposition was studied in male rats fed flavored, nutritionally controlled, purified diets in a multichoice "cafeteria" (CAF) arrangement. Serum insulin, L-3,3',5-triiodothyronine (T3) and thyroxine (T4) levels were also determined. Rats fed nutritionally balanced diets containing a variety of preferred flavors and textural forms ad libitum in a CAF design did not consume more energy nor did they gain more weight than rats fed a single choice of nutritionally balanced diet with no modifications in flavor or texture. Feeding high fat, high sucrose diets containing a variety of flavors in a CAF arrangement resulted in higher energy intake, body weight gain, lipid content in fat pads and serum T3 levels than did feeding the nutritionally balanced diet. However, the high fat diet with no added flavors also resulted in an energy intake, body weight gain and lipid content of fat pads at a level equal or close to that produced by the CAF feeding of the flavored, high fat, high sucrose diet. It is therefore concluded that the effect of a variety of food flavors on hyperphagia and fat deposition is of minor importance in purified diets compared to the stimulating effect of the fat in the diet.


Asunto(s)
Grasas de la Dieta/metabolismo , Aromatizantes , Preferencias Alimentarias , Tejido Adiposo Pardo/metabolismo , Análisis de Varianza , Animales , Peso Corporal , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/efectos adversos , Ingestión de Energía , Hiperfagia/etiología , Hígado/análisis , Masculino , Fenómenos Fisiológicos de la Nutrición , Tamaño de los Órganos , Ratas , Ratas Endogámicas , Tiroxina/análisis , Triyodotironina/análisis
11.
Proc Soc Exp Biol Med ; 178(3): 392-401, 1985 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2579403

RESUMEN

Rats fed a diet containing 2.5% sodium saccharin (NaSacc) displayed a rapid (24-36 hr) increase in tryptic and chymotryptic activity in the lower half of the small intestine and the cecum compared with control animals. Cecal pH of rats fed NaSacc was lower than controls. The effect of NaSacc on enzymatic activity of intestinal contents and on indigenous bacterial microflora was studied further in vitro. Intestinal contents incubated anaerobically with or without NaSacc revealed that the presence of NaSacc led to higher tryptic and chymotryptic activity and higher final pH. Changes in pH do not appear, however, to be important for the increased proteolytic activity induced by NaSacc since autodigestion of trypsin and chymotrypsin in filter-sterilized samples was only slightly affected by pH during in vitro incubation. Amylolytic activity, on the other hand, was stabilized by higher pH values. Saccharin stabilized chymotryptic and led to almost complete loss of amylolytic activity during incubation of filter-sterilized samples maintained at adjusted pH values. The amount of reducing sugars remaining in the NaSacc-containing contents from either cecum (in vivo) or from in vitro incubation of unsterilized small intestinal samples was greater than controls not containing NaSacc. The growth of six bacterial strains isolated from small intestinal contents and incubated in laboratory media was inhibited by NaSacc. Extracellular proteolytic activity from bacterial sources was undetectable after incubation of intestinal bacteria in laboratory media. The present results suggest that the effect of NaSacc upon digestive enzyme composition in the small intestine of rats is not mediated through a direct physiological effect of NaSacc on pancreatic exocrine secretion. It is hypothesized that an inhibition of enzymatic activity by NaSacc in the small intestine and the bacteriostatic effect of NaSacc on bacteria may be responsible for the increased proteolytic activity observed in vivo in the cecum following the feeding of a NaSacc-containing diet to rats.


Asunto(s)
Amilasas/metabolismo , Bacterias/aislamiento & purificación , Quimotripsina/metabolismo , Intestino Delgado/microbiología , Sacarina/farmacología , Tripsina/metabolismo , Animales , Escherichia coli/efectos de los fármacos , Concentración de Iones de Hidrógeno , Intestino Delgado/enzimología , Lactobacillus/efectos de los fármacos , Masculino , Ratas , Ratas Endogámicas , Temperatura
14.
J Nutr ; 112(11): 2104-15, 1982 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-6182277

RESUMEN

Growing rats were fed either 10 to 17% protein (casein) diets whose taste was changed daily by addition of aversive stimuli. Under these circumstances food intake and body weight gain were reduced compared with controls fed unadulterated diets. More amylolytic activity per gram pancreas was found in rats fed a 10% protein, aversive diet and in their pair-fed controls fed restricted amounts of an unadulterated diet compared with ad libitum controls. More amylolytic activity per gram chyme of small intestine was also found in rats fed less than ad libitum amounts of a 10% protein diet. The chymotrypsin activity in the pancreas of rats fed a 17% protein, aversive diet was greater than in that of control animals or that of the pair-fed animals. The 2- to 10-fold higher proteolytic activity found in the small intestine and especially in the large intestine and feces of rats fed the aversive diet was specifically related to the adulteration of the diet with sodium saccharin. Feeding a diet containing sodium saccharin led to lower cecal pH. Under conditions of the present experiments, changes in digestive enzyme activity are not directly related to the aversive taste of the diet.


Asunto(s)
Amilasas/metabolismo , Caseínas/administración & dosificación , Quimotripsina/metabolismo , Dieta/efectos adversos , Sacarina/efectos adversos , Tripsina/metabolismo , alfa-Amilasas/metabolismo , Animales , Citratos/efectos adversos , Ácido Cítrico , Dieta/normas , Heces/análisis , Intestinos/enzimología , Masculino , Páncreas/enzimología , Ratas , Cloruro de Sodio/efectos adversos , Sacarosa/análogos & derivados
16.
Anat Rec ; 195(3): 443-6, 1979 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-507400

RESUMEN

The distribution of taste buds on the fungiform and circumvallate papillae of the cow tongue has been determined. The two tongues studied were from Holstein-Friesian cows four to six years of age; they contained 14,765 and 21,691 taste buds, respectively. The tip of the tongue is well supplied with fungiform papillae, and the posterior portion contains the circumvallate papillae. The midportion of the tongue contains relatively few taste papillae. The fungiform papillae contained 1,580 and 1,838 taste buds on the two tongues, respectively, and the circumvallate papillae were estimated to contain 13,185 and 19,853 taste buds. The highest concentration of taste buds therefore occurs in the circumvallate papillae; these relatively few papillae contain approximately 90% of the taste buds. On a circumvallate papilla, taste buds are found only on the papillary sidewall, with none either on the apical surface of the papilla or on the outer wall of the moat.


Asunto(s)
Papilas Gustativas/anatomía & histología , Lengua/anatomía & histología , Animales , Bovinos
17.
J Nutr ; 109(2): 339-44, 1979 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-430235

RESUMEN

The effect of dietary-induced vitamin B-6 (B-6) deficiency on the intake of the taste solutions, sodium chloride (NaCl), sodium saccharin (NaSacc), quinine sulfate (QS), and hydrochloric acid (HCl) was studied using a 48 hour, two-bottle choice technique. The B-6 deficient group demonstrated increased preference to 1.5 X 10(-1) and 3.0 X 10(-1) M NaCl compared to control ad libitum fed and control pair-fed groups. Total fluid intake on NaCl test days was also elevated in the B-6 deficient rats. There was no significant difference in the mean preference to NaSacc, QS, or HCl among the three groups. Adrenal hypertrophy was observed in the deficient rats. There was no change in the plasma level of Na and Zn but there was a reduction in urinary Na excretion. When the deficient rats were replenished by intraperitoneal injection of pyridoxine.HCl and feeding with the control diet containing adequate B-6, the increased preference for NaCl was extinguished, suggesting that the preference alteration was reversible. Urinary Na excretion also returned to normal.


Asunto(s)
Ácido Clorhídrico , Quinina , Sacarina , Cloruro de Sodio , Gusto/fisiología , Deficiencia de Vitamina B 6/fisiopatología , Glándulas Suprarrenales/patología , Hipertrofia , Piridoxina/uso terapéutico , Sodio/metabolismo , Deficiencia de Vitamina B 6/tratamiento farmacológico , Zinc/sangre
20.
J Nutr ; 107(9): 1653-8, 1977 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-561170

RESUMEN

The acceptability of heated soybean meal (HS) compared to raw soybean flakes (RS) was studied by means of diet selection in free choice situations. The selection by rats of diets containing HS over those containing RS was shown in short- and long-term preference tests. Texture did not seem to be an important factor in the acceptability difference between HS and RS. Rats selected a less nutritious diet containing RS + sodium saccharin (appealing taste) over a diet containing HS + sucrose octaacetate (aversive taste) for an initial 6 to 7 days, suggesting that post-ingestional factors did not markedly affect the acceptability during that period. However, after this initial period, the rats selected the diet of higher nutritive value, even though it had added sucrose octaacetate. Preference tests before and after producing anosmia indicated that RS contains an aversive odor(s) which could be removed by vacuum treatment. Heated soybean meal was found to contain an appealing taste stimulus (i) which could also be removed by vacuum treatment.


Asunto(s)
Preferencias Alimentarias , Glycine max , Animales , Dieta , Calor , Masculino , Trastornos del Olfato/inducido químicamente , Trastornos del Olfato/fisiopatología , Ratas , Olfato , Glycine max/normas , Gusto , Tiopental
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