Nutritional status alters the mRNA expressions of galanin and its receptors in taste buds of rats / 生理学报

The nutritional and metabolic status alters the peripheral taste perception and food intake by participating in the modulation of taste information integration. The taste receptors and neuropeptides in the taste buds are the important targets of this modulation process. To explore the effects of nutritional status on the expressions of galanin and its receptors in the taste buds, we compared the mRNA levels of galanin and its specific receptor GalR2 in the taste buds among the high-fat diet induced obese rats (HF), chronically restricted diet rats (CR) and control rats. The high-fat diet, half of chow diet, and normal chow diet were given to HF, CR and control groups for 6 weeks, respectively. The body weight and some metabolic indexes, including blood glucose, triglyceride and cholesterol levels were detected. The mRNA expressions of galanin and its receptors in taste buds were determined using real-time PCR. Results showed that compared with control rats, the body weights, levels of blood glucose and triglyceride were significantly elevated in HF rats; while the mRNA expressions of galanin and GalR2 were dramatically decreased. However, galanin mRNA expression in CR rats was increased to 2.3 times of that in control group. Considering the results obtained from our previous studies, we conclude that the behavioral changes in tasting choice of HF rats may be related to the expressions of galanin and GalR2 in the taste buds. The changes of galanin and GalR2 in taste buds are involved in the peripheral mechanism of nutritional status regulating taste perception and feeding behavior in rats.

Differential expression of bone morphogenetic protein and activin membrane-bound inhibitor in mouse adipose tissues and primary preadipocytes / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression profiles of bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) during the development of mouse adipose tissue.</p><p><b>METHODS</b>The total RNA was extracted for real-time PCR for amplification of BAMBI mRNA from the suprascapular brown adipose tissue (BAT) and subcutaneous (inguinal) and visceral (gonadal) white adipose tissue (sWAT and vWAT, respectively) of mice at various embryonic and postnatal stages, as well as from isolated primary preadipocytes during differentiation.</p><p><b>RESULTS</b>In BAT, BAMBI mRNA levels exhibited a transient increase, peaking at day 0 (D0) and declined thereafter. sWAT and vWAT could be isolated from mice from postnatal D21 onwards, in which BAMBI mRNA levels were the highest and decreased at 8 weeks and 6 months. BAMBI mRNA levels were also significantly reduced in primary preadipocytes isolated from vWAT after induced differentiation. BAMBI mRNA expression level was higher in vWAT than in sWAT and BAT at the same developmental stages.</p><p><b>CONCLUSION</b>BAMBI is differentially expressed in different adipose tissues and developmental stages, which supports the hypothesis that BAMBI plays a pivotal role in the development of adipose tissues.</p>

Leptin receptor of the hind brain nuclei is involved in the conditioned taste preference of rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>Conditioned taste preference (CTP) is a taste learning reflex by which an animal learns to prefer a substance which tastes not well and has been studied with much interest in recent years. However, the neural substrates of CTP are less known. This study aimed to determine the possible neural path- ways of CTP and whether serum leptin level and the leptin receptor (OB-Rb) in the hind brain are involved following CTP formation.</p><p><b>METHODS</b>We established CTP of quinine in rats with a 2-bottle preference test. The serum leptin concentrations were detected, the expression of c-fos in the rat brain was tested to determine the nuclei in relation with establishment of CTR Finally, the OB-Rb mRNA expression was examined by RT-qPCR assay in parabrachial nucleus (PBN) and the nucleus of the solitary tract (NST) of the hind brain.</p><p><b>RESULTS</b>Compared with control group, the level of serum leptin was higher in the CTP group (4.58 ± 0.52 vs 1.67 ± 0.25 µg/L, P < 0.01); increased c-fos positive cells were found in the anterior hypothalamus (AH, 221.75 ± 4.96 vs. 178.50 ± 6.63 cells/mm², P < 0.05), the basal lateral amygdala (BLA, 70.75 ± 6.17 vs 56.50 ± 3.62 cells/ mm², P < 0.05) and the nucleus of the solitary tract (NST, 41.25 ± 1.32 vs 32.50 ± 1.02 cells/mm², P < 0.05). But in ventromedial nucleus of the hypothalamus (VMH, 20.75 ± 2.73 vs 38.5 ± 1.54 per 1 mm², P < 005), PBN (21.50 ± 2.24 vs 36.25 ± 1.49 cells/mm², P < 0.05) and the central nucleus of the amygdala (CeA, 22.25 ± 1.53 vs 35.50 ± 2.11 cells/mm², P < 0.05), the number of c-fos positive cells was decreased in the CTP group. In addition, we found OB-Rb mRNA expression in PBN of CTP group rats was higher than that of control group (0.95 ± 0.055 vs 0.57 ± 0.034, P < 0.05), while there was no significant difference of OB-Rb mRNA expression in NST between the two groups.</p><p><b>CONCLUSION</b>Nuclei AH, BLA, NST, VMH, PBN and CeA participate in the formation of CTP. Leptin and its receptor in PBN may be involved in the formation and maintenance of CTP.</p>

Progress in the effects of injury and regeneration of gustatory nerves on the taste functions in animals / 生理学报

The sensor of the taste is the taste bud. The signals originated from the taste buds are transmitted to the central nervous system through the gustatory taste nerves. The chorda tympani nerve (innervating the taste buds of the anterior tongue) and glossopharyngeal nerve (innervating the taste buds of the posterior tongue) are the two primary gustatory nerves. The injuries of gustatory nerves cause their innervating taste buds atrophy, degenerate and disappear. The related taste function is also impaired. The impaired taste function can be restored after the gustatory nerves regeneration. The rat model of cross-regeneration of gustatory nerves is an important platform for research in the plasticity of the central nervous system. The animal behavioral responses and the electrophysiological properties of the gustatory nerves have changed a lot after the cross-regeneration of the gustatory nerves. The effects of the injury, regeneration and cross-regeneration of the gustatory nerves on the taste function in the animals will be discussed in this review. The prospective studies on the animal model of cross-regeneration of gustatory nerves are also discussed in this review. The study on the injury, regeneration and cross-regeneration of the gustatory nerves not only benefits the understanding of mechanism for neural plasticity in gustatory nervous system, but also will provide theoretical basis and new ideas for seeking methods and techniques to cure dysgeusia.

Equity of health service utilization of urban residents: data from a western Chinese city / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Getting medical treatment is still difficult and expensive in western China. Improving the equity of basic health services is one of the tasks of the new healthcare reform in China. This study aimed to analyze the parallel and vertical equity of health service utilization of urban residents and then find its influencing factors.</p><p><b>METHODS</b>In August 2011, a household survey was conducted at 18 communities of Baoji City by multi-stage stratified random sampling. Based on the survey data, we calculated a concentration index of health service utilization for different income residents and a difference index of different ages. We then investigated the influencing factors of health service utilization by employing the Logistic regression model and log-linear regression model.</p><p><b>RESULTS</b>The two-week morbidity rate of sampled residents was 19.43%, the morbidity rate of chronic diseases was 21.68%, and the required hospitalization rate after medical diagnosis was 11.36%. Among out-patient service utilization, the two-week out-patient rate, number of two-week out-patients, and out-patient expense had good parallel and vertical equity, while out-patient compensation expense had poor parallel and vertical equity. The inpatient service utilization, hospitalization rate, number of inpatients, days stayed in the hospital, and inpatient expense had good parallel equity, while inpatient compensation expense had poor parallel equity. While the hospitalization rate and number of inpatients had vertical equity, the days stayed in hospital, inpatient expense, and inpatient compensation expense had vertical inequity.</p><p><b>CONCLUSIONS</b>Urban residents' health was at a low level and there was not good health service utilization. There existed rather poor equity of out-patient compensation expense. The equity of inpatient service utilization was quite poor. Income difference and the type of medical insurance had great effects on the equity of health service utilization.</p>

Blood pressure salt sensitivity in male offspring rats is programmed by perinatal high-salt diet / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the gender differences in perinatal high-salt diet programming of blood pressure and salt sensitivity in offspring Sprague-Dawley rats and explore the mechanisms.</p><p><b>METHODS</b>The rats were fed with high-salt diet (8% NaCl) or normal salt diet (1% NaCl) during the perinatal period. Body weight changes were monitored, and blood pressure and heart rate were measured by non-invasive tail-cuff methods in both male and female offspring rats. The components of renin-angiotensin-aldosterone system (RAAS) in both the serum and brain tissue, and hormones related with stress reaction were detected using radioimmunology methods.</p><p><b>RESULTS</b>Perinatal high-salt diet did not affect adolescent blood pressure in both genders, but significantly increased salt sensitivity in male offspring rats. Perinatal high-salt diet also increased serum angiotensin II (ANG II) while decreased corticotropin-releasing hormone (CRH) and cortisol in male offsprings, as compared with the normal salt diet group. No similar results were found in the female offspring rats.</p><p><b>CONCLUSION</b>There is a significant gender difference in perinatal high-salt diet programming of offspring blood pressure salt sensitivity, and the mechanisms may involve the disturbance of the RAAS function and stress reaction.</p>

Glutaminergic neurons expressing c-Fos in the brainstem and amygdala participate in signal transmission and integration of sweet taste / 南方医科大学学报

<p><b>OBJECTIVE</b>To examine the role of glutaminergic neurons in the transmission and integration of the sweat taste information in the brain stem and the amygdala.</p><p><b>METHODS</b>Conscious Sprague-Dawley rats were subjected to oral sweet taste or water (control) stimulations. The activated neurons were identified by detecting c-Fos expression in taste-related brain areas, and the glutaminergic neurons by detecting vesicular glutamate transpoter-3 (VGLUT3).</p><p><b>RESULTS</b>Compared with control group, the rats with oral sucrose solution stimulation exhibited significantly increased c-Fos-expressing and double-labeled neurons in the nucleus of the solitary tract (NST), the parabrachial nucleus (PBN) and the amygdala.</p><p><b>CONCLUSION</b>Neurons in the NST, PBN and amygdala are activated after oral sweet taste stimulation. The sweet taste perception at different levels in the CNS is partly mediated by glutamate.</p>

GABAergic neurons in the central nucleus of amygdala modulate sodium appetite in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine whether the GABA-containing neurons in rat central nucleus of amygdala (CeA) can be activated by acute sodium deprivation.</p><p><b>METHODS</b>Acute sodium depletion was induced by subcutaneous injection of furosemide in rats followed by 24 h of dietary sodium deprivation. The rats underwent 0.3 mol/L NaCl/distilled water two bottle choice test, and the activated neurons were labeled and identified with GABA/Fos-double labeling immunohistochemistry.</p><p><b>RESULTS</b>The rats with acute sodium depletion exhibited significantly more numerous c-fos-positive neurons and GABA/Fos double-labeled neurons in the CeA than the control group (P<0.01, P<0.05). Consumption of 0.3 mol/L NaCl significantly increased the number of c-fos and GABA/Fos double labeled neurons compared to the distilled water group (P<0.001, P<0.01).</p><p><b>CONCLUSION</b>GABAergic neurons in the CeA may play an inhibitory role in the regulation of sodium intake in rats with acute sodium depletion.</p>

Inhibitory responses of parabrachial neurons evoked by taste stimuli in rat / 生理学报

In the present study, the responses of inhibitory gustatory neurons in the parabrachial nucleus (PBN) to four basic taste stimuli NaCl, HCl, quinine HCl (QHCl) and sucrose were examined using single-unit recording technique in anesthetized rats. A total of 18 inhibitory taste neurons in the PBN were obtained. Spontaneous firing rates of these inhibitory neurons were 0.2-5.5 Hz with mean firing rate of (2.15+/-0.31) Hz. Most of the neurons responded to more than one of the basic taste qualities. The inhibitory responses to taste occurred quickly and lasted 5-80 s in different PBN neurons. According to the responsive characteristics to the four basic taste stimuli, the neurons could be classified as NaCl-best (n=8), HCl-best (n=3), QHCl-best (n=3), and sucrose-best (n=4). The breadth of tuning of NaCl-best neurons was the highest (0.945). Inhibitory responsive neurons had feeble discrimination among sapid stimuli or aversive stimuli. These results suggest that there exist inhibitory taste neurons in the PBN. These neurons may play some useful roles in precise transmission of taste information and the taste coding for hedonic and aversive tastes.

Effects of the central amygdaloid nucleus lesions on tastants intake in rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of central amygdaloid nucleus (CeA) on the evaluation of taste in rats, and explore the mechanisms of the CeA in modulating the feeding behavior.</p><p><b>METHODS</b>By using two-bottle choice test, we measured the consumption of serials concentrations of NaCl, citric acid (CA), quinine HCl (QHCl) and sucrose in bilateral CeA lesioned rats, and compared the results to those in sham lesioned rats.</p><p><b>RESULTS</b>The CeA-lesioned rats exhibited a lower preference for NaCl at concentrations of 0.03; 0.1 and 0.3 mol/L, for CA at concentrations of 0.01; 0.1 and 1.0 mmol/L, and for QHCl at 10; 20 and 50 micromol/L, but the preference for serials of concentrations of sucrose are similar between two groups. By comparing the intake of adjacent concentrations of sapid solutions, it indicated that CeA-lesioned rats showed a lower distinction between adjacent concentrations of NaCl, CA and QHCl. However, the total consumption (water and tastants) during all the test sessions was not significantly different between two groups of rats.</p><p><b>CONCLUSION</b>Lesion of CeA decreases the intake of tastants solution, but the effects on different concentrations of solution are different. It suggests that the CeA plays an important role in the normal response to exteroceptive food stimuli through impacting on the assessment of taste and altering the preference threshold of gustatory stimuli.</p>

Blocking of AMPA receptors in the central amygdaloid nucleus modulates the parabrachial nucleus taste responses in rats / 生理学报

Taste responses in the parabrachial nucleus (PBN) are significantly affected by stimulation or lesion of the central nucleus of the amygdala (CeA). To examine if the glutamate receptors in the CeA are involved in this modulation, the effects of microinjection of 6-cyano-7-nitro-quinoxaline-2, 3-dione (CNQX), an AMPA receptor antagonist, into the CeA on the activities of PBN taste neurons were observed by using extracellular recording technique. Responses of PBN taste neurons to taste stimuli were observed before and after CNQX administered to the CeA. In general, drug administration produced a time-dependent suppress of the responses in 30% PBN taste neurons, with the firing rates to HCl and QHCl were significantly lowered (P<0.05). According to the best-stimulus category, 40% NaCl-best (6/15), 30% HCl-best (3/10) and 20% QHCl-best (1/5) neurons decreased their responses to at least one basic taste stimulus after CNQX injection. In HCl- and QHCl-best neurons, the main responses were significantly inhibited after drug injections (P<0.01). The correlation coefficient of responses between the NaCl and the other three tastants decreased after drug administration to the CeA. These results suggest that AMPA receptors within the CeA may be involved in the descending modulation in the PBN taste neurons.

Effects of the central amygdaloid nucleus lesions on the gustatory responses in the parabrachial nucleus in rats / 生理学报

To access the role of the central nucleus of the amygdala (CeA) in the gustatory activity in the pontine parabrachial nucleus (PBN), the responses to four prototypical taste stimuli (NaCl, HCl, QH2SO4 and sucrose) in the PBN were observed before and after bilateral electrolytic lesion of the CeA in the urethane-anesthetized rat. Of 29 neurons, 14 were classified as NaCl-best, 9 as HCl-best, 3 as QH2SO4-best and 3 sucrose-best. After CeA lesions, the response rates to HCl and QH2SO4 were statistically higher across all PBN neurons (P<0.01). According to the best-stimulus category, the effects on the responses to HCl and QH2SO4 were similarly subjected to these modulations in NaCl-best, HCl-best and QH2SO4-best neurons. Correlation analysis indicated that the CeA lesion depressed the effect on the chemical selection between NaCl and QH2SO4. These findings suggest that the CeA plays an important role in the taste coding at the pontine level and it may be involved in mediating the feeding behavior via modulating the gustatory responses.

Change of serum leptin and leptin receptors immunoreactivity in the brain following intraoral infusions of chemical solutions in rats / 中国应用生理学杂志

<p><b>AIM</b>To determining whether the level of serum leptin altered and whether the expression of leptin receptor immunoreactivity changed following taste stimuli.</p><p><b>METHODS</b>After intraoral infusions of chemical solutions, which included 3 mol/L sucrose, 5 mmol/L sodium saccharin, 0.1 mol/L NaCl, 0.01 mol/L HCl, 1 mmol/L quinine H2SO4 and 0.1 mol/L monosodium glutamate, serum leptin concentration were measured by using rat leptin RIA kit. Immunohistochemistry ABC method was used for brain sections with high-specify-goat antiserum against leptin receptors.</p><p><b>RESULTS</b>Comparing with the control group (intraoral infusion of distilled water), the level of serum leptin only in sweet group (sucrose an d saccharin) raised (P < 0.05). Many neuronal cell bodies and dendritic processes showed leptin receptors immunoreactivity (LR-IR) in many brain regions, such as amygdala, hypothalamus, parabrachial nucleus and nucleus of the solitary tract, which had intense relationship with taste and feeding. But the number of positive-stained cells showed no difference in aforementioned brain regions between the taste stimuli group and the control group.</p><p><b>CONCLUSION</b>After intraoral stimuli of sweet substances, the serum leptin concentration increased. LR-IR cells exist in amygdala which plays a critical role in the initiation and guidance of feeding. This findings led us study possible effects of leptin on taste responses. Probably, leptin influences food intake through the sense of taste.</p>