首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 453 毫秒
1.
Intense physical activity is associated with biological adaptations involving hormones and trace elements. Zinc supplementation may affect plasma copper concentration, thyroid-stimulating hormone (TSH), thyroid hormones, insulin, and glucose homeostasis, but data in athletes are scarce. The aim of this study was to evaluate in competitive athletes (cyclists, n = 7, 32 ± 8 years) the effect of zinc supplementation (22 mg/day as zinc gluconate) during 30 days, and discontinuation using placebo (maltodextrin) during the following 30 days, on plasma zinc and copper concentrations, serum thyroid hormones, insulin and glucose levels, and HOMA2-IR. Compared to baseline, plasma zinc and Zn:Cu plasma ratio increased, but plasma copper decreased after zinc supplementation (day 30) and discontinuation (day 60) (p < 0.05). Zn supplementation and discontinuation had no effect on TSH, T3, and T4. Fasting serum insulin and HOMA2-IR increased (27% and 47%, respectively) on day 60 compared to baseline (p = 0.03), suggesting a delayed effect of zinc supplementation. Moreover, plasma zinc was positively associated with serum insulin (r = 0.87, p = 0.009) and HOMA2-IR (r = 0.81, p = 0.03) after zinc supplementation (day 30), indicating that supplemental zinc may impair glucose utilization in cyclists.  相似文献   

2.
Functional evidence suggests that nitric oxide (NO) signalling in the rostral ventrolateral medulla (RVLM) is cGMP-dependent and that this pathway is impaired in hypertension. We examined cGMP expression as a marker of active NO signalling in the C1 region of the RVLM, comparing adult (>18 weeks) Wistar–Kyoto (WKY, n = 4) and spontaneously hypertensive rats (SHR, n = 4). Double label immunohistochemistry for cGMP-immunoreactivity (IR) and C1 neurons [as identified by phenylethanolamine N-methyltransferase (PNMT-IR) or tyrosine hydroxylase TH-IR)], or neuronal NO synthase (nNOS) neurones, failed to reveal cGMP-IR neurons in the RVLM of either strain, despite consistent detection of cGMP-IR in the nucleus ambiguus (NA). This was unchanged in the presence of isobutylmethylxanthine (IBMX; 0.5 mM, WKY, n = 4, SHR  = 2) and in young animals (WKY, 10-weeks, n = 3). Incubation of RVLM-slices (WKY, 10-weeks, n = 9) in DETA-NO (100 μm; 10 min) or NMDA (10 μM; 2 min) did not uncover cGMP-IR. In all studies, cGMP was prominent within the vasculature. Soluble guanylate cyclase (sGC)-IR was found throughout neurones of the RVLM, but did not co-localise with PNMT, TH or nNOS-IR neurons (WKY, 10-weeks, n = 6). Results indicate that within the RVLM, cGMP is not detectable using immunohistochemistry in the basal state and cannot be elicited by phosphodiesterase inhibition, NMDA receptor stimulation or NO donor application. Kellysan Powers-Martin and Anna M. Barron contributed equally.  相似文献   

3.
Responses of the neurons of the lateral and ventromedial hypothalamic regions (HL andHvm, respectively), as well as of the area of the dorsal hypothalamus (aHd) and the projection region of the medial forelimb bundle (MFB), evoked by stimulation of the proreal cortex (field 8), cingular cortex (field 24), pyriform lobula (periamigdalar cortex), and hippocampus (CA3) were studied in acute experiments on cats under ketamine anesthesia. Distributions of the latent periods of the responses recorded from hypothalamic neurons at stimulation of the above cortical structures were analyzed. The responses were classified into primary excitatory and primary inhibitory. Stimulation of the proreal gyrus evoked four times more excitatory responses than inhibitory responses. With stimulation of the cingular gyrus, the ratio of excitatory/inhibitory responses was 1.5∶1. Stimulation of the pyriform cortex evoked activatory and inhibitory responses with a similar probability. With hippocampal stimulation, inhibitory responses appeared two times more frequently than excitatory reactions. The hypothalamus was found to be a zone of wide convergence: one-half of all responding neurons in theHL andHvm responded to stimulations of two or more tested cortical zones. In 26% of the cells, only excitatory convergence was observed, while in 10% only inhibitory convergence was found; 21% of the cells revealed mixed convergence.  相似文献   

4.
While it is known that the aorta stiffens with location and age, little is known about the underlying mechanisms that govern these alterations. The purpose of this study was to investigate the relationship between the anisotropic biomechanical behavior and extracellular matrix microstructure of the human aorta and quantify how each changes with location and age. A total of 207 specimens were harvested from 5 locations (ascending n = 33, arch n = 38, descending n = 54, suprarenal n = 52, and abdominal n = 30) of 31 autopsy donor aortas (aged 3 days to 93 years). Each specimen underwent planar biaxial testing in order to derive quantitative biomechanical endpoints of anisotropic stiffness and compliance. Quantitative measures of fiber alignment and degree of fiber alignment were also generated on the same samples using a small-angle light scattering (SALS) technique. Circumferential and axial stiffening occurred with age and increased from the proximal to distal aorta, and the abdominal region was found to be more stiff than all others (p ≤ 0.006). Specimens from donors aged 61 and above were drastically more stiff than younger specimens (p < 0.001) and demonstrated greater circumferential compliance and axial stiffening (p < 0.001). Fiber direction for all ages and locations was predominantly circumferential (p < 0.001), and the degree of fiber alignment was found to increase with age (p < 0.001). Our results demonstrate that the aorta becomes more biomechanically and structurally anisotropic after age 60; with significant changes occurring preferentially in the abdominal aorta, these changes may play an important role in the predisposition of disease formation (e.g., aneurysm) in this region with age.  相似文献   

5.
Sexual differentiation of the brain occurs between d 30 and 70 in the fetal lamb. The objective of this experiment was to determine if maternal fatness affects fetal steroid production and expression of their receptors which may ultimately alter endocrine systems postnatally. Fetuses were collected from ewes fed at either 100% (Control; n = 5) or 150% (Fat; n = 6) of NRC recommendations from 60 d prior to breeding until collection at 75 d of gestation. Hypothalamic and amygdala neural tissues were collected from twin male/female fetuses. Serum concentrations of testosterone were greater (P < 0.001) in male fetuses compared to female fetuses. Further, male fetuses from Fat ewes had greater (P < 0.05) serum concentrations of testosterone than male fetuses from Control ewes, but differences in testicular steroidogenic enzyme mRNA were not detected (P = 0.18). Quantity of hypothalamic mRNA for estrogen receptor (ER) β tended (P = 0.1) to be influenced by a sex by treatment interaction. Messenger RNA for ER-β was greater in female fetuses than male fetuses from Control ewes (P = 0.05). Although amount of ER-β mRNA did not differ among male fetuses (P = 0.7), amounts tended to be less (P = 0.07) in female fetuses from Fat ewes compared to those from Control ewes, and did not differ (P ≥ 0.8) from male fetuses. Hypothalamic ER-α mRNA tended (P = 0.1) to be less in fetuses from Fat ewes compared to Control fetuses but was not influenced (P = 0.3) by fetal sex or their interaction. Amount of mRNA for hypothalamic progesterone receptor tended (P = 0.06) to be greater in male fetuses than female fetuses and tended to be less (P = 0.06) in fetuses from Fat ewes than in Control fetuses, but did not differ by any sex by treatment interaction (P = 0.6). Hypothalamic RNA for the androgen receptor did not differ by sex, dam nutritional treatment, or the interaction. Likewise, amygdala RNA for the estrogen or androgen receptor did not differ (P ≥ 0.3) by sex, treatment, or their interaction. Dam fatness appears to decrease the expression of progesterone receptor, ER-α, and decrease amount of ER-β in the female fetuses while increasing circulating concentrations of testosterone in male fetuses. Altered expression of hypothalamic receptor genes by the uterine environment may affect adult responses to stress, sexual behavior and/or the pattern of gonadotropin release in response to gonadal steroids.  相似文献   

6.

Background

Plasma and urine levels of the potent vasodilator Ang-(1–7) are elevated in mid and late pregnancy and are correlated with elevated placental angiogenesis, fetal blood flow, and rapid fetal growth. We hypothesized that Ang-(1–7), its receptor (Mas1) and the enzymes involved in Ang-(1–7) production (ACE2 and Membrane metallo-endopeptidase; MME) are down regulated in response to glucocorticoid administration contributing to IUGR.

Methods

Pregnant female Sprague–Dawley rats were injected with dexamethasone (DEX; 0.4 mg/kg/day) starting from 14 day gestation (dg) till sacrifice at 19 or 21 dg while control groups were injected with saline (n?=?6/group). The gene and protein expression of ACE2, MME, Ang-(1–7) and Mas1 receptor in the placental labyrinth (LZ) and basal zones (BZ) were studied.

Results

DEX administration caused a reduction in LZ weight at 19 and 21 dg (p?<?0.001). IUGR, as shown by decreased fetal weights, was evident in DEX treated rats at 21 dg (p?<?0.01). ACE2 gene expression was elevated in the LZ of control placentas at 21 dg (p?<?0.01) compared to 19 dg and DEX prevented this rise at both gene (p?<?0.01) and protein levels (p?<?0.05). In addition, Ang-(1–7) protein expression in LZ was significantly reduced in DEX treated rats at 21 dg (p?<?0.05). On the other hand, Mas1 and MME were upregulated in LZ at 21 dg in both groups (p?<?0.05 and p?<?0.001, respectively).

Conclusion

The results of this study indicate that a reduced expression of ACE2 and Ang-(1–7) in the placenta by DEX treatment may be responsible for IUGR and consequent disease programming later in life.
  相似文献   

7.
We investigated the regulation of the pharyngeal and upper esophageal reflexes during swallowing in eel. By retrograde tracing from the muscles, the motoneurons of the upper esophageal sphincter (UES) were located caudally within the mid-region of the glossopharyngeal-vagal motor complex (mGVC). In contrast, the motoneurons innervating the pharyngeal wall were localized medially within mGVC. Sensory pharyngeal fibers in the vagal nerve terminated in the caudal region of the viscerosensory column (cVSC). Using the isolated brain, we recorded 51 spontaneously active neurons within mGVC. These neurons could be divided into rhythmically (n = 8) and continuously (n = 43) firing units. The rhythmically firing neurons seemed to be restricted medially, whereas the continuously firing neurons were found caudally within mGVC. The rhythmically firing neurons were activated by the stimulation of the cVSC. In contrast, the stimulation of the cVSC inhibited firing of most, but not all the continuously firing neurons. The inhibitory effect was blocked by prazosin in 17 out of 38 neurons. Yohimbine also blocked the cVSC-induced inhibition in five of prazosin-sensitive neurons. We suggest that the neurons in cVSC inhibit the continuously firing motoneurons to relax the UES and stimulate the rhythmically firing neurons to constrict the pharynx simultaneously.  相似文献   

8.
Inhibitory control skills are important for academic outcomes across childhood, but it is unknown whether inhibitory control is implicated in the association between genetic variation and academic performance. This study examined the relationship between a GWAS-based (EduYears) polygenic score indexing educational attainment (EA PGS) and inhibitory control in early (Mage = 3.80 years) and middle childhood (Mage = 9.18 years), and whether inhibitory control in early childhood mediated the relation between EA PGS and academic skills. The sample comprised 731 low-income and racially/ethnically diverse children and their families from the longitudinal early steps multisite study. EA PGS predicted middle childhood inhibitory control (estimate = 0.09, SE = 0.05, p < 0.05) and academic skills (estimate = 0.18, SE = 0.05, p < 0.01) but did not predict early childhood inhibitory control (estimate = 0.08, SE = 0.05, p = 0.11); thus, mediation was not tested. Sensitivity analyses showed that effect sizes were similar across European and African American groups. This study suggests that inhibitory control could serve as a potential mechanism linking genetic differences to educational outcomes.  相似文献   

9.
One frequent chronic syndrome of Chagas’ disease is megacolon, an irreversible dilation of a colonic segment. Extensive enteric neuron loss in the affected segment is regarded as key factor for deficient motility. Here, we assessed the quantitative balance between cholinergic and nitrergic neurons representing the main limbs of excitatory and inhibitory colonic motor innervation, respectively. From surgically removed megacolonic segments of four patients, each three myenteric wholemounts (from non-dilated oral, megacolonic and non-dilated anal parts) was immunohistochemically triple-stained for choline acetyltransferase, neuronal nitric oxide synthase (NOS) and the panneuronal human neuronal protein Hu C/D. Degenerative changes were most pronounced in the megacolonic and anal regions, e.g. bulked, honeycomb-like ganglia with few neurons which were partly enlarged or atrophic or vacuolated. Neuron counts from each 15 ganglia of 12 megacolonic wholemounts were compared with those of 12 age- and region-matched controls. Extensive neuron loss, mainly in megacolonic and anal wholemounts, was obvious. In all three regions derived from megacolonic samples, the proportion of NOS-positive neurons (control: 55%) was significantly increased: in non-dilated oral parts to 61% (p = 0.003), in megacolonic regions to 72% (p < 0.001) and in non-dilated anal regions to 78% (p < 0.001). We suggest the chronic dilation of megacolonic specimens to be due to the preponderance of the nitrergic, inhibitory input to the intestinal muscle. However, the observed neuronal imbalance was not restricted to the dilated regions: the non-dilated anal parts may be innervated by ascending, cholinergic axons emerging from less affected, more anally located regions.  相似文献   

10.
The aim of this study was to examine whether voles performing stereotypic behaviours (Ster) differed in physical welfare from voles, which did not develop stereotypies (N-Ster). The chosen variables were reproductive success and capacity to survive barren housing conditions. Furthermore, effect of weight on proneness to develop stereotypic behaviours were examined. Singly housed Ster (n = 62) in barren cages showed superior survival when compared to similar housed N-Ster (n = 38; p = 0.002). Furthermore, Ster females (n = 25) gave birth to both a first and second litter faster than N-Ster females (n = 14; p ≤ 0.019). Litter size, number of weanlings and proportion of barren females did not differ between Ster and N-Ster, but pups from Ster experienced a higher pre-weaning mortality in the second litter (p = 0.0095). Voles classed as Ster within age 6 month (n = 55) weighed less than same aged N-Ster (n = 45) already from weaning (21 days; p = 0.0204). However, weight at weaning, whether LIGHT (weight ≤ median; n = 47) or HEAVY (weight > median; n = 53), had no effect on subsequent development of stereotypies in terms of either onset age or fraction which developed stereotypies. The results suggested that Ster had better physical welfare, as reflected in better survival, than N-Ster when housed singly and a higher reproductive success when used as breeders.  相似文献   

11.
The responsiveness of spontaneously active neurons in the subfornical organ (SFO) of adult ducks to angiotensin II (ANGII), norepinephrine (NE), isoproterenol (Iso, -agonist), phenylephrine (Phe, 1-agonist) and clonidine (Clo, 2-agonist) was investigated in brain slices with extracellular recording technique. 64% (n=90) of the neurons increased their activity after superfusion with ANGII, the rest were unresponsive. Application of NE activated 10 and inhibited 8 neurons (n=22); the excitation being correlated with an excitatory ANGII responsiveness of the same neurons and the inhibition with the absence of an ANGII responsiveness. Iso activated 74% (n=58) and Clo inhibited 88% (n=16) of the investigated neurons. Phe did not have an effect on the majority (60%) of the neurons and produced both excitatory and inhibitory actions on the remaining cells. These results offer a plausible explanation for the dose dependent dipsogenic effect of Iso and the failure of NE to elicit dose dependent drinking, which can be explained by its dual, excitatory and inhibitory effect on SFO neurons. It is further concluded, that peripherally applied Iso exerts its dipsogenic action in high concentration by a direct excitatory effect on SFO neurons via the open blood brain barrier. Under physiological conditions, afferent neuronal input of still unknown origin might specifically modulate the activity of SFO neurons, because plasma concentrations of NE are probably not high enough to activate SFO neurons from the blood side of the blood brain barrier.Abbreviations ACSF artificial cerebrospinal fluid - ANGII angiotensin II - Clo clonidine - Iso isoproterenol - NE norepinephrine - NTS nucleus of the solitary tract - Phe phenylephrine - SFO subfornical organ  相似文献   

12.
Neuronal responses to stimulation of the proreal (field 8) and cingular (field 24) cortices, pyriform lobe (periamygdalar cortex), and hippocampus (CA3) were studied in the lateral (HL) and ventromedial (Hvm) hypothalamus, dorsal hypothalamic region (aHd), and projection region of the medial forelimb bundle (MFB); single and repeated (series of a 6–300 sec−1 frequency) stimuli were used. At single stimulations, the minimum proportion of inhibitory responses with respect to excitatory effects was observed when the neocortex (the proreal gyrus) was stimulated; this proportion became successively greater at stimulations of the intermediate cortex (the cingular gyrus) and paleocortex (the pyriform cortex), while stimulation of the archicortex (the hippocampus) evoked mostly inhibitory responses. At repeated stimulation of the cortical structures, inhibitory responses prevailed in the neurons under study: their total number was nearly four times larger than that of excitatory reactions. The response patterns to single and serial stimulations of the cortical structures allowed us to demonstrate: (i) significant diversity of the influences received by hypothalamic neurons from the cortical structures and (ii) the dependence of the pattern of these influences on the phylogenetic specificity of the above structures.  相似文献   

13.
The ratio between circulating levels of leptin and soluble leptin receptor (sOB-R), the free leptin index (FLI), is used as a marker of leptin resistance. Therefore, the aim of our study was to investigate the FLI in mild pre-eclamptic pregnancies in a nested case–control study within a prospective observational study. Circulating levels of leptin and sOB-R levels rise significantly during pregnancy in healthy (p < 0.05) (n = 46) and pre-eclamptic pregnancies (p < 0.05) (n = 20). Serum levels of leptin were significantly higher in pre-eclamptic compared to healthy pregnancies at second and third trimesters of pregnancy (p < 0.05). Additionally, serum levels of sOB-R were significantly lower in pre-eclamptic pregnancies during the second and third trimesters of pregnancy compared to healthy pregnancies (p < 0.05). Moreover, we found that FLI did not vary significantly during pregnancy in healthy women (p > 0.05), while it increases in pre-eclamptic pregnancies (p < 0.05). Indeed, FLI was significantly higher at second and third trimesters of pregnancy in pre-eclamptic compared to healthy pregnancies (p < 0.05). In addition, FLI was significantly higher in the luteal phase compared with the follicular phase of the menstrual cycle in eumenorrheic women (p < 0.05). Receiver operating characteristic (ROC) curve analysis revealed the ability of leptin (AUC = 0.72) and FLI (AUC = 0.67) as a reliable predictor for mild pre-eclampsia during the second trimester of pregnancy. In conclusion, our findings show that FLI were significantly increased in mild pre-eclamptic pregnancies and allowed us to hypothesize that this rise might alter leptin bioavailability and bioactivity which might lead to the sympathetic hyperactivity and the hypertensive disorders during pregnancy.  相似文献   

14.
Objective Alpha hemoglobin-stabilizing protein (AHSP) inhibits the production of reactive oxygen species in various cells, including erythrocytes. Reduced AHSP can mean reduced protection from stressors. Our objective was to investigate whether AHSP is involved in the response to stress in pregnancy. Study design Placentas were collected from normal term pregnancies (n = 10) and pregnancies complicated by HELLP (n = 10), intrauterine growth restriction (IUGR; n = 10) or fetal death (IUFD; n = 6). AHSP messenger RNA (mRNA) and protein were determined using real time quantitative polymerase chain reaction (PCR) and Western blot, respectively. All statistical analyses were performed by using the GraphPad Prism Software. Differences were considered significant at p < 0.05. Results Placental AHSP mRNA level in HELLP (4.16E10−4 ± 1.77) and IUFD (4.19E10−4 ± 3.37) were significantly decreased compared with controls (28.47E10−4 ± 14.86; p < 0.01), whereas levels in the IUGR group (7.55E10−4 ± 6.4) showed a trend toward being lower but the difference did not reach statistical significance. Western blot analysis results indicate a no significant increase of ASHP protein in the HELLP syndrome group and a significant decrease in the IUFD group compared with controls. There was no significant difference between the IUGR and control groups. Conclusion ASHP mRNA expression in the placenta is decreased in complicated pregnancies, and it may be involved in the pathogenic mechanisms leading to the adverse pregnancy outcome. This paper was presented as a poster at the 27th Annual Meeting of the Society for Maternal Fetal Medicine; San Francisco, CA, USA, February 5–10, 2007. Monica Emanuelli and Davide Sartini contributed equally to this paper.  相似文献   

15.
This study aimed to reveal the prognostic role of the Hippo pathway in different histopathological subtypes of renal cell carcinoma (RCC). The TCGA-KIRC (n = 537), TCGA-KIRP (n = 291) and TCGA-KICH (n = 113), which contain data about clear cell (ccRCC), papillary (pRCC) and chromophobe RCC (chRCC), respectively, were investigated. Gene Set Variation Analysis was used to compare the activity of many pathways within a single sample. Oncogenic pathway-related expression differed between cases of ccRCC involving low and high Hippo pathway activity. There were two subsets of ccRCC, in which the cancer exhibited lower and higher Hippo signalling activity, respectively, compared with normal tissue. In the ccRCC cohort, lower Hippo pathway activity was associated with a higher clinical stage (p < 0.001). The Hippo pathway (HR = 0.29; 95% CI = 0.17–0.50, p < 0.001), apoptosis (HR = 6.02; 95% CI = 1.47–24.61; p = 0.013) and the p53 pathway (HR = 0.09; 95% CI = 0.02–0.36; p < 0.001) were identified as independent prognostic factors for ccRCC. The 5-year overall survival of the ccRCC patients with low and high Hippo pathway activity were 51.9% (95% CI = 45.0–59.9) and 73.6% (95% CI = 67.8–79.9), respectively. In conclusion, the Hippo pathway plays an important role in the progression of ccRCC. Low Hippo pathway activity is associated with poor outcomes in ccRCC, indicating the tumour suppressor function of this pathway.  相似文献   

16.
The development of a competitive ELISA for the detection of brucella-specific antibodies in bovines is described. Anti-brucella guinea pig serum was used as a source of competing antibodies. Lipo-polysaccharide purified from inactivated B. abortus S19 culture was used as antigen for the development of the assay. Sera from cattle were used in the competitive ELISA, rose bengal test and a commercial indirect ELISA. The following cattle sera were tested: (i) known positive sera (n = 80) (ii) known negative sera (n = 100) and (iii) field sera (n = 1184). Based on the receiver operating characteristics curve analysis and frequency distribution of the percentage of inhibition, 30% inhibition was considered the cut-off for positive and negative results. The sensitivity and specificity estimate on comparison with the commercial indirect ELISA was 94.87 and 92.12% respectively. The competitive ELISA described is a simple method for the routine screening of animal sera for detecting Brucella-specific antibodies.  相似文献   

17.
In order to explore the proteomic signatures of epicardial adipose tissue (EAT) related to the mechanism of heart failure with reduced and mildly reduced ejection fraction (HFrEF/HFmrEF) and heart failure (HF) with preserved ejection fraction (HFpEF), a comprehensive proteomic analysis of EAT was made in HFrEF/HFmrEF (n = 5) and HFpEF (n = 5) patients with liquid chromatography–tandem mass spectrometry experiments. The selected differential proteins were verified between HFrEF/HFmrEF (n = 20) and HFpEF (n = 40) by ELISA (enzyme-linked immunosorbent assay). A total of 599 EAT proteins were significantly different in expression between HFrEF/HFmrEF and HFpEF. Among the 599 proteins, 58 proteins increased in HFrEF/HFmrEF compared to HFpEF, whereas 541 proteins decreased in HFrEF/HFmrEF. Of these proteins, TGM2 in EAT was down-regulated in HFrEF/HFmrEF patients and was confirmed to decrease in circulating plasma of the HFrEF/HFmrEF group (p = 0.019). Multivariate logistic regression analysis confirmed plasma TGM2 could be an independent predictor of HFrEF/HFmrEF (p = 0.033). Receiver operating curve analysis indicated that the combination of TGM2 and Gensini score improved the diagnostic value of HFrEF/HFmrEF (p = 0.002). In summary, for the first time, we described the proteome in EAT in both HFpEF and HFrEF/HFmrEF and identified a comprehensive dimension of potential targets for the mechanism behind the EF spectrum. Exploring the role of EAT may offer potential targets for preventive intervention of HF.  相似文献   

18.
Interneurons of the substantia gelatinosa (SG) form a complex synaptic network in the dorsal horn of the spinal cord. The properties of miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs, respectively) were studied in spinal cord slices of 3- to 4-week-old rats. The reversal potentials of the currents were close to 0 mV for excitatory and –70 mV for inhibitory events. Under recording conditions close to physiological ones (holding potential –40 mV, temperature 32°C, low intracellular [Cl]), the mean rise times of these currents were, respectively, 1.0 and 1.8 msec. The decay of the currents was monoexponential in the majority of occurrences (94 and 91.4%), with a time constant (τ) of 2.7 msec for mEPSCs and 7.2 msec for mIPSCs. A part (8.6%) of mIPSCs had an additional slow component with τ = 30.1 msec. All mEPSCs were blocked by 10 mM CNQX, an antagonist of the AMPA/kainate subtype of glutamate receptors. Monoexponential mIPSCs were blocked by 1 mM strychnine, an antagonist of glycine receptors, while two-component mIPSCs required the additional presence of 10 mM bicuculline, a blocker of GABAA receptors. Only two cells of 23 (~9%) demonstrated pure GABA-ergic mIPSCs (τ = 26.2 msec). It is concluded that, under physiological conditions, AMPA/kainate but not NMDA receptors mediate excitatory synaptic transmission in SG neurons. Synaptic inhibition is mediated predominantly by glycine receptors, with mild fractions of IPSCs provided by GABA-ergic transmission and GABA/glycine co-release.  相似文献   

19.
Dogs demonstrate an age-related cognitive decline, which may be related to a decrease in the concentration of omega-3 polyunsaturated fatty acids (n-3 PUFA) in the brain. Medium chain triglycerides (MCT) increase fatty acid oxidation, and it has been suggested that this may raise brain n-3 PUFA levels by increasing mobilization of n-3 PUFA from adipose tissue to the brain. The goal of the present study was to determine whether dietary MCT would raise n-3 PUFA concentrations in the brains of aged dogs. Eight Beagle dogs were randomized to a control diet (n = 4) or an MCT (AC-1203) enriched diet (n = 4) for 2 months. The animals were then euthanized and the parietal cortex was removed for phospholipid, cholesterol and fatty acid determinations by gas-chromatography. Dietary enrichment with MCT (AC-1203) resulted in a significant increase in brain phospholipid and total lipid concentrations (P < 0.05). In particular, n-3 PUFA within the phospholipid, unesterified fatty acid, and total lipid fractions were elevated in AC-1203 treated subjects as compared to controls (P < 0.05). Brain cholesterol concentrations did not differ significantly between the groups (P > 0.05). These results indicate that dietary enrichment with MCT, raises n-3 PUFA concentrations in the parietal cortex of aged dogs.  相似文献   

20.
The aim of this study is to compare the gross morphology of the placentae and the morphometry of terminal villi and terminal villous capillaries in pregnancies complicated by idiopathic intrauterine growth restriction (IUGR) with those of normal pregnancies. 75 placentae were collected between April 2010 and March 2011. 50 placentae were associated with idiopathic IUGR and 25 were from controls. Insertion of cords, placental weights and diameters were noted. Hematoxylin and eosin-stained wax sections were analyzed stereologically. Growth of terminal villi and fetal capillaries was assessed by estimating total and mean surface areas. Villous capillarization was monitored using capillary:villus surface ratio. Measurements were done using image analysis system. In comparison with the control group, idiopathic IUGR placentae are significantly smaller (p = 0.000) and lighter (p = 0.000). In majority of IUGR (68%) and control (60%) cases, eccentric insertion of cord is noted. In idiopathic IUGR group, there is a significant decrease in the total areas of both terminal villi (p = 0.048) and their capillaries (p = 0.000) and a significant decrease in number of both terminal villi (p = 0.000) and their capillaries (p = 0.001), also, capillarization index is significantly smaller (p = 0.038). Idiopathic IUGR is associated with reduced growth of placental terminal villi and fetal capillaries and this is accompanied by changes in measures of villous capillarization as compared with those of control placentae. Further investigations of idiopathic IUGR placentae are necessary, especially considering the histopathological changes that could affect the fetomaternal exchange, with a note that strict distinction should be made between idiopathic and nonidiopathic IUGR placentae.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号