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The relationship between obesity and taste, especially sweet taste, has been and is of interest. From this point of view of a small primate, the lesser mouse lemur (Microcebus murinus), is of particular interest. It goes through a yearly cycle of physiological changes, one of which is an extreme variation in body weight of up to 100%. This occurs concomitantly with significant changes of the animal's liking for sucrose; measured by two-bottle preference tests, the threshold for sucrose changes from 28-45 in lean to 77-105 mM in obese animals. It is possible that a change in peripheral taste sensitivity might be the cause for these preference changes. To test this possibility we studied the ability of M.murinus to taste sucrose with electrophysiological and conditioned taste aversion techniques. The electrophysiological recordings were obtained from the chorda tympani proper nerve in two heavy and three lean animals. We did not record any difference between the two groups in their neural response to a series of sucrose concentrations. Conditioned taste aversion experiments with 200 mM sucrose as conditioning stimulus and 50 and 200 mM sucrose as test stimuli gave similar results. No difference was found between three heavy and four lean animals; both groups rejected the sucrose concentrations. The results support the notion that the seasonal variations in preference threshold to sucrose were unrelated to the ability of M.murinus to taste sucrose

The intake of six sweeteners was recorded together with their effects on the impulse activity of the chorda tympani proper nerve during their application to the tongue. The sweeteners were: acetosulfam, aspartame, D-tryptophan, glycine, xylitol and thaumatin. They were used at human equi-sweet concentrations. In all species, D-tryptophan was strongly preferred and gave a significant response, while aspartame and thaumatin gave neither a significant behavioral nor a significant neural response. Acetosulfam, glycine and xylitol elicited neural responses, but their behavioral effects differed from a rejection in some species to a preference in others. Miraculin, which has a sweetness inducing effect in man, showed this effect only in the platyrrhinean species and not in the prosimian

Application of gymnemic acid (GA) on the tongue depresses the taste of sucrose in man. This effect, as indicated by electrophysiological responses, has been found to be absent in three nonhuman primate species. In the present behavioral study the effect of GA on taste responses in 22 primate species, with two subspecies, and 12 human subjects has been investigated. In all the nonhuman primates studied, including the Pongidae which are closely related to man, GA did not suppress the response to sucrose, only in man did GA have a depressing effect

The effect of intra-arterial injection of the proteins monellin, thaumatin and miraculin on the activity of the chorda tympani proper nerve were recorded in the rhesus monkey (Macaca mulatto) and the rat (Sprague-Dawley). The substances were injected into the blood stream to the lingual artery. It was found that monellin and thaumatin elicited a response only in the monkey and not in the rat. Acetylated thaumatin, a tasteless substance, gave no increase of the nerve activity. Miraculin had no effect in either species. NaCl, sucrose and citric acid injected intra-arterially gave a response in both species. It is concluded that the responses to intra-arterial injections were caused by stimulation of the taste buds and not nerve fibers. The results suggest there are taste receptors also on the parts of the taste cells not facing the oral cavity. The finding that there was no cross-adaptation between intra-arterial and oral application supports this conclusion

An aqaeous extract from the pulp of the plant Pentadiplandra brazzeana Baillon (Pentadiplandraceae) yielded a strong sweet-tasting material. This sweet principle was isolated by water extraction, ultrafiltration and gel filtration. The conclusion that this substance must be of a proteinaceous nature was based on amino acid analysis, characteristic UV-absorption spectrum and positive colour reaction with Coomassie brilliant blue. The mol. wt of the subunit of the sweet protein was estimated to be ˜ 12 000 daltons. The sweetness intensity of the whole protein was ˜ 500 times that of sucrose on a weight basis. The taste response in a Rhesus monkey to a 0.1 % solution was comparable to the response to a 0.02 % monellin solution. We propose the name ‘pentadin' for this sweet-tasting protein and present a few comments about the possible origin of such sugar mimics

Contains reports on four research projects., National Institutes of Health (Grant 1 P01 GM-14940-02), Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E), National Institutes of Health (Grant 5 TO1 GM-01555-02)

The relationship between obesity and taste, especially sweet taste, has been and is of interest. From this point of view of a small primate, the lesser mouse lemur (Microcebus murinus), is of particular interest. It goes through a yearly cycle of physiological changes, one of which is an extreme variation in body weight of up to 100%. This occurs concomitantly with significant changes of the animal's liking for sucrose; measured by two-bottle preference tests, the threshold for sucrose changes from 28-45 in lean to 77-105 mM in obese animals. It is possible that a change in peripheral taste sensitivity might be the cause for these preference changes. To test this possibility we studied the ability of M.murinus to taste sucrose with electrophysiological and conditioned taste aversion techniques. The electrophysiological recordings were obtained from the chorda tympani proper nerve in two heavy and three lean animals. We did not record any difference between the two groups in their neural response to a series of sucrose concentrations. Conditioned taste aversion experiments with 200 mM sucrose as conditioning stimulus and 50 and 200 mM sucrose as test stimuli gave similar results. No difference was found between three heavy and four lean animals; both groups rejected the sucrose concentrations. The results support the notion that the seasonal variations in preference threshold to sucrose were unrelated to the ability of M.murinus to taste sucrose

Application of gymnemic acid (GA) on the tongue depresses the taste of sucrose in man. This effect, as indicated by electrophysiological responses, has been found to be absent in three nonhuman primate species. In the present behavioral study the effect of GA on taste responses in 22 primate species, with two subspecies, and 12 human subjects has been investigated. In all the nonhuman primates studied, including the Pongidae which are closely related to man, GA did not suppress the response to sucrose, only in man did GA have a depressing effect

The intake of six sweeteners was recorded together with their effects on the impulse activity of the chorda tympani proper nerve during their application to the tongue. The sweeteners were: acetosulfam, aspartame, D-tryptophan, glycine, xylitol and thaumatin. They were used at human equi-sweet concentrations. In all species, D-tryptophan was strongly preferred and gave a significant response, while aspartame and thaumatin gave neither a significant behavioral nor a significant neural response. Acetosulfam, glycine and xylitol elicited neural responses, but their behavioral effects differed from a rejection in some species to a preference in others. Miraculin, which has a sweetness inducing effect in man, showed this effect only in the platyrrhinean species and not in the prosimian

The effect of intra-arterial injection of the proteins monellin, thaumatin and miraculin on the activity of the chorda tympani proper nerve were recorded in the rhesus monkey (Macaca mulatto) and the rat (Sprague-Dawley). The substances were injected into the blood stream to the lingual artery. It was found that monellin and thaumatin elicited a response only in the monkey and not in the rat. Acetylated thaumatin, a tasteless substance, gave no increase of the nerve activity. Miraculin had no effect in either species. NaCl, sucrose and citric acid injected intra-arterially gave a response in both species. It is concluded that the responses to intra-arterial injections were caused by stimulation of the taste buds and not nerve fibers. The results suggest there are taste receptors also on the parts of the taste cells not facing the oral cavity. The finding that there was no cross-adaptation between intra-arterial and oral application supports this conclusion

An aqaeous extract from the pulp of the plant Pentadiplandra brazzeana Baillon (Pentadiplandraceae) yielded a strong sweet-tasting material. This sweet principle was isolated by water extraction, ultrafiltration and gel filtration. The conclusion that this substance must be of a proteinaceous nature was based on amino acid analysis, characteristic UV-absorption spectrum and positive colour reaction with Coomassie brilliant blue. The mol. wt of the subunit of the sweet protein was estimated to be ˜ 12 000 daltons. The sweetness intensity of the whole protein was ˜ 500 times that of sucrose on a weight basis. The taste response in a Rhesus monkey to a 0.1 % solution was comparable to the response to a 0.02 % monellin solution. We propose the name ‘pentadin' for this sweet-tasting protein and present a few comments about the possible origin of such sugar mimics

Application of gymnemic acid (GA) on the tongue depresses the taste of sucrose in man. This effect, as indicated by electrophysiological responses, has been found to be absent in three nonhuman primate species. In the present behavioral study the effect of GA on taste responses in 22 primate species, with two subspecies, and 12 human subjects has been investigated. In all the nonhuman primates studied, including the Pongidae which are closely related to man, GA did not suppress the response to sucrose, only in man did GA have a depressing effect

The effect of intra-arterial injection of the proteins monellin, thaumatin and miraculin on the activity of the chorda tympani proper nerve were recorded in the rhesus monkey (Macaca mulatto) and the rat (Sprague-Dawley). The substances were injected into the blood stream to the lingual artery. It was found that monellin and thaumatin elicited a response only in the monkey and not in the rat. Acetylated thaumatin, a tasteless substance, gave no increase of the nerve activity. Miraculin had no effect in either species. NaCl, sucrose and citric acid injected intra-arterially gave a response in both species. It is concluded that the responses to intra-arterial injections were caused by stimulation of the taste buds and not nerve fibers. The results suggest there are taste receptors also on the parts of the taste cells not facing the oral cavity. The finding that there was no cross-adaptation between intra-arterial and oral application supports this conclusion

The relationship between obesity and taste, especially sweet taste, has been and is of interest. From this point of view of a small primate, the lesser mouse lemur (Microcebus murinus), is of particular interest. It goes through a yearly cycle of physiological changes, one of which is an extreme variation in body weight of up to 100%. This occurs concomitantly with significant changes of the animal's liking for sucrose; measured by two-bottle preference tests, the threshold for sucrose changes from 28-45 in lean to 77-105 mM in obese animals. It is possible that a change in peripheral taste sensitivity might be the cause for these preference changes. To test this possibility we studied the ability of M.murinus to taste sucrose with electrophysiological and conditioned taste aversion techniques. The electrophysiological recordings were obtained from the chorda tympani proper nerve in two heavy and three lean animals. We did not record any difference between the two groups in their neural response to a series of sucrose concentrations. Conditioned taste aversion experiments with 200 mM sucrose as conditioning stimulus and 50 and 200 mM sucrose as test stimuli gave similar results. No difference was found between three heavy and four lean animals; both groups rejected the sucrose concentrations. The results support the notion that the seasonal variations in preference threshold to sucrose were unrelated to the ability of M.murinus to taste sucrose

The relationship between phylogeny and taste is of growing interest. In this study we present recordings from the chorda tympani proper (CT) nerve of two lemuriforme primates, the lesser mouse lemur (Microcebus murinus) and the mongoose lemur (Eulemur mongoz), to an array of taste stimuli which included the sweeteners acesulfame-K, alitame, aspartame, D-glucose, dulcin, monellin, neohesperidin dihydrochalcone (NHDHC), saccharin, sodium superaspartame, stevioside, sucralose (TGS), sucrose, suosan, thaumatin and xylitol, as well as the non-sweet stimuli NaC1, citric acid, tannin and quinine hydrochloride. In M.murinus the effects of the taste modifiers gymnemic acid and miraculin on the CT response were recorded. Conditioned taste aversion (CTA) experiments in M.murinus and two-bottle preference (TBP) tests in E.mongoz were also conducted. We found that all of the above tastants except thaumatin elicited a CT response in both species. The CTA technique showed that M.murinus generalized from sucrose to monellin but not to thaumatin. The intake of aspartame, ranging in concentration from 0.1 to 30 mM was measured in E.mongoz with TBP tests. At no concentration did we see a preference, but there was a significant rejection of 10 and 30 mM aspartame (P←0.025). Miraculin had no effects on the CT response to acids, and gymnemic acid did not selectively suppress the CT response to sucrose or that of any other sweeteners. The absence of ability to taste thaumatin in these species supports the dichotomy between catarrhine and non-catarrhine species. The difference in results with thaumatin and monellin indicate that their sweet moieties are not identical. It also points to a phylogenetic difference in taste within the prosimian group. Further, the results with aspartame indicate that the perception of sweetness from aspartame is limited to catarrhine species. Finally, neither miraculin nor gymnemic acid exhibit the same taste modifying effects in lemuriformes as they do in hom

An aqaeous extract from the pulp of the plant Pentadiplandra brazzeana Baillon (Pentadiplandraceae) yielded a strong sweet-tasting material. This sweet principle was isolated by water extraction, ultrafiltration and gel filtration. The conclusion that this substance must be of a proteinaceous nature was based on amino acid analysis, characteristic UV-absorption spectrum and positive colour reaction with Coomassie brilliant blue. The mol. wt of the subunit of the sweet protein was estimated to be ˜ 12 000 daltons. The sweetness intensity of the whole protein was ˜ 500 times that of sucrose on a weight basis. The taste response in a Rhesus monkey to a 0.1 % solution was comparable to the response to a 0.02 % monellin solution. We propose the name ‘pentadin' for this sweet-tasting protein and present a few comments about the possible origin of such sugar mimics

The intake of six sweeteners was recorded together with their effects on the impulse activity of the chorda tympani proper nerve during their application to the tongue. The sweeteners were: acetosulfam, aspartame, D-tryptophan, glycine, xylitol and thaumatin. They were used at human equi-sweet concentrations. In all species, D-tryptophan was strongly preferred and gave a significant response, while aspartame and thaumatin gave neither a significant behavioral nor a significant neural response. Acetosulfam, glycine and xylitol elicited neural responses, but their behavioral effects differed from a rejection in some species to a preference in others. Miraculin, which has a sweetness inducing effect in man, showed this effect only in the platyrrhinean species and not in the prosimian