Neuro-endocrine markers such as salivary alpha amylase (sAA) and cortisol (CORT) play an important role in establishing human responses to stressful events. Whereas sAA levels reflect sympathetic system activity, salivary cortisol appears to be a valid measure for HPA axis activity. Although many studies looked at either sAA or CORT responses in reaction to stress, work still has to be done to look at the way these systems interact, especially when both systems are activated. Additionally, sex effects in CORT responses have been investigated relatively often, but possible sex differences in sAA levels and responses, or the way both systems interact has not been the focus of sufficient studies to yield a univocal conclusion.
In this study we presented a group of healthy participants (n = 80) with two mildly stressful tasks, consisting of an aversive picture rating task and a cold pressor stress (CPS) task. The second task was compared with a control task. We expected a rise in sAA level in response to the first task and sAA as well as CORT responses on the second task and explored the interaction between the two responses.
Results indicate that salivary alpha amylase (sAA) is indeed a sensitive marker in both psychologically and physically induced arousal paradigms, whereas a cortisol response was only observed in the CPS task. Men had higher sAA levels than women during the complete course of the study, but men and women were comparable in their responsivity to the tasks. No strong correlations between sAA and CORT responses were found.
ARTICLE
Human spit contains 1,116 unique proteins
U.S. researchers have identified all 1,116 unique proteins found in human saliva glands, a discovery they said on Tuesday could usher in a wave of convenient, spit-based diagnostic tests that could be done without the need for a single drop of blood.
Natural-born painkiller found in human saliva
Saliva from humans has yielded a natural painkiller up to six times more powerful than morphine, researchers say.
The substance, dubbed opiorphin, may spawn a new generation of natural painkillers that relieve pain as well as morphine but without the addictive and psychological side effects of the traditional drug.
When the researchers injected a pain-inducing chemical into rats’ paws, 1 milligram of opiorphin per kilogram of body weight achieved the same painkilling effect as 3 milligrams of morphine.
The substance was so successful at blocking pain that, in a test involving a platform of upended pins, the rats needed six times as much morphine as opiorphin to render them oblivious to the pain of standing on the needle points.
Anti-depressive angle
“Its pain-suppressive effect is like that of morphine,” says Catherine Rougeot at the Pasteur Institute in Paris, France, who led the research. “But we have to test its side effects as it is not a pure painkiller,” she says. “It may also be an anti-depressive molecule.”
Rougeot and colleagues discovered that opiorphin works in nerve cells of the spine by stopping the usual destruction of natural pain-killing opiates there, called enkephalins.
Opiorphin is such a simple molecule that it should be possible to synthesise it and produce large quantities without having to isolate it from saliva, Rougeot explains. Alternatively, it might be possible to find drugs which trigger patients’ bodies to produce more of the molecule themselves.
The substance, dubbed opiorphin, may spawn a new generation of natural painkillers that relieve pain as well as morphine but without the addictive and psychological side effects of the traditional drug.
When the researchers injected a pain-inducing chemical into rats’ paws, 1 milligram of opiorphin per kilogram of body weight achieved the same painkilling effect as 3 milligrams of morphine.
The substance was so successful at blocking pain that, in a test involving a platform of upended pins, the rats needed six times as much morphine as opiorphin to render them oblivious to the pain of standing on the needle points.
Anti-depressive angle
“Its pain-suppressive effect is like that of morphine,” says Catherine Rougeot at the Pasteur Institute in Paris, France, who led the research. “But we have to test its side effects as it is not a pure painkiller,” she says. “It may also be an anti-depressive molecule.”
Rougeot and colleagues discovered that opiorphin works in nerve cells of the spine by stopping the usual destruction of natural pain-killing opiates there, called enkephalins.
Opiorphin is such a simple molecule that it should be possible to synthesise it and produce large quantities without having to isolate it from saliva, Rougeot explains. Alternatively, it might be possible to find drugs which trigger patients’ bodies to produce more of the molecule themselves.
Effects of Aerobic Exercise on Uric Acid, Total Antioxidant Activity, Oxidative Stress, and Nitric Oxide in Human Saliva
The aim of this study was to determine the effect of aerobic exercise on uric acid (UA), total antioxidant activity (TAA), lipid hydroperoxides, and nitric oxide (NO) metabolites in human saliva. Twenty-four healthy male and female subjects were studied during a 10,000-m race. Saliva samples were collected 1 h before and immediately after exercise. The NO concentration was determined by the Griess reaction, UA by enzymatic method, TAA by the ABTS method, and lipid hydroperoxide by the ferrous iron/xylenol orange (FOX) method. A repeated measures ANOVA was used to examine the effect of aerobic exercise on salivary UA, TAA, lipid hydroperoxides, and NO metabolites. Aerobic exercise caused an increase in both salivary UA and TAA, and a decrease in salivary lipid hydroperoxide. There was no, however, change in nitrite concentration. These results suggested that aerobic exercise-induced increment in both UA and TAA seems to inhibit lipid hydroperoxide generation, a marker of oxidative stress in human saliva.
Alternative Catalytic Anions Differentially Modulate Human α-Amylase Activity and Specificity
A mechanistic study of the essential allosteric activation of human pancreatic α-amylase by chloride ion has been conducted by exploring a wide range of anion substitutions through kinetic and structural experiments. Surprisingly, kinetic studies indicate that the majority of these alternative anions can induce some level of enzymatic activity despite very different atomic geometries, sizes, and polyatomic natures. These data and subsequent structural studies attest to the remarkable plasticity of the chloride binding site, even though earlier structural studies of wild-type human pancreatic α-amylase suggested this site would likely be restricted to chloride binding. Notably, no apparent relationship is observed between anion binding affinity and relative activity, emphasizing the complexity of the relationship between chloride binding parameters and the activation mechanism that facilitates catalysis. Of the anions studied, particularly intriguing in terms of observed trends in substrate kinetics and their novel atomic compositions were the nitrite, nitrate, and azide anions, the latter of which was found to enhance the relative activity of human pancreatic α-amylase by nearly 5-fold. Structural studies have provided considerable insight into the nature of the interactions formed in the chloride binding site by the nitrite and nitrate anions. To probe the role such interactions play in allosteric activation, further structural analyses were conducted in the presence of acarbose, which served as a sensitive reporter molecule of the catalytic ability of these modified enzymes to carry out its expected rearrangement by human pancreatic α-amylase. These studies show that the largest anion of this group, nitrate, can comfortably fit in the chloride binding pocket, making all the necessary hydrogen bonds. Further, this anion has nearly the same ability to activate human pancreatic α-amylase and leads to the production of the same acarbose product. In contrast, while nitrite considerably boosts the relative activity of human pancreatic α-amylase, its presence leads to changes in the electrostatic environment and active site conformations that substantially modify catalytic parameters and produce a novel acarbose rearrangement product. In particular, nitrite-substituted humnan pancreatic α-amylase demonstrates the unique ability to cleave acarbose into its acarviosine and maltose parts and carry out a previously unseen product elongation. In a completely unexpected turn of events, structural studies show that in azide-bound human pancreatic α-amylase, the normally resident chloride ion is retained in its binding site and an azide anion is found bound in an embedded side pocket in the substrate binding cleft. These results clearly indicate that azide enzymatic activation occurs via a mechanism distinct from that of the nitrite and nitrate anions.
Salivary -amylase: A measure associated with satiety and subsequent food intake in humans
Food intake regulation in humans involves various central and peripheral mechanisms. In this study salivary amylase was examined for functioning as a measure of satiety and food intake. In a 1.25-h session, 32 fasted subjects were given a preload of starch-based custard (849 kJ) followed by ad libitum intake of this custard. Before and after preload intake and after ad libitum consumption, both satiety ratings and -amylase were analysed. Perceived satiety and amylase were increased after preload and ad libitum consumption. Across subjects, the individual amount of ad libitum intake was negatively correlated to -amylase levels before this intake, whereas it was positively associated with -amylase activity after ad libitum consumption. In conclusion, salivary amylase systematically increases upon food consumption and satiation, and serves therefore as a potential measure of satiety and subsequent food intake.
ARTICLE
ARTICLE
Formation of an adduct by clenbuterol, a β-adrenoceptor agonist drug, and serum albumin in human saliva at the acidic pH of the stomach
Clenbuterol (CLB) is an antiasthmatic drug used also illegally as a lean muscle mass enhancer in both humans and animals. CLB and amine-related drugs in general are nitrosatable, thus raising concerns regarding possible genotoxic/carcinogenic activity. Oral administration of CLB raises the issue of its possible transformation by salivary nitrite at the acidic pH of gastric juice. In acidic human saliva CLB was rapidly transformed to the CLB arenediazonium ion. This suggests a reaction of CLB with salivary nitrite, as confirmed in aerobic HNO2 solution by a drastic decrease in nitric oxide, nitrite, and nitrate. In human saliva, both glutathione and ascorbic acid were able to inhibit CLB arenediazonium formation and to react with preformed CLB arenediazonium. The effect of ascorbic acid is particularly pertinent because this vitamin is actively concentrated within the gastric juice. EPR spin trapping experiments showed that preformed CLB arenediazonium ion was reduced to the aryl radical by ascorbic acid, glutathione, and serum albumin, the major protein of saliva. As demonstrated by anti-CLB antibodies and MS, the CLB–albumin interaction leads to the formation of a covalent drug–protein adduct, with a preference for Tyr-rich regions. This study highlights the possible hazards associated with the use/abuse of this drug.
ARTICLE
ARTICLE
Arsenic Speciation Analysis in Human Saliva
Background: Determination of arsenic species in human saliva is potentially useful for biomonitoring of human exposure and studying arsenic metabolism. Arsenic speciation in saliva has not been reported previously.
Methods: We separated arsenic species in saliva using liquid chromatography (LC) and quantified them by inductively coupled plasma mass spectrometry. We further confirmed the identities of arsenic species by LC coupled with electrospray ionization tandem mass spectrometry. These methods were successfully applied to the determination of arsenite (AsIII), arsenate (AsV), and their methylation metabolites, monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV), in >300 saliva samples collected from people who were exposed to varying concentrations of arsenic.
Results: The mean (range) concentrations (µg/L) in the saliva samples from 32 volunteers exposed to background levels of arsenic were AsIII 0.3 [not detectable (ND) to 0.7], AsV 0.3 (ND to 0.5), MMAV 0.1 (ND to 0.2), and DMAV 0.7 (ND to 2.6). Samples from 301 people exposed to increased concentrations of arsenic in drinking water showed detectable AsIII in 99%, AsV in 98%, MMAV in 80%, and DMAV in 68% of samples. The mean (range) concentrations of arsenic species in these saliva samples were (in µg/L) AsIII 2.8 (0.1–38), AsV 8.1 (0.3–120), MMAV 0.8 (0.1–6.0), and DMAV 0.4 (0.1–3.9). Saliva arsenic correlated with drinking water arsenic. Odds ratios for skin lesions increased with saliva arsenic concentrations. The association between saliva arsenic concentrations and the prevalence of skin lesions was statistically significant (P <0.001).
Conclusions: Speciation of AsV, AsIII, MMAV, and DMAV in human saliva is a useful method for monitoring arsenic exposure.
Methods: We separated arsenic species in saliva using liquid chromatography (LC) and quantified them by inductively coupled plasma mass spectrometry. We further confirmed the identities of arsenic species by LC coupled with electrospray ionization tandem mass spectrometry. These methods were successfully applied to the determination of arsenite (AsIII), arsenate (AsV), and their methylation metabolites, monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV), in >300 saliva samples collected from people who were exposed to varying concentrations of arsenic.
Results: The mean (range) concentrations (µg/L) in the saliva samples from 32 volunteers exposed to background levels of arsenic were AsIII 0.3 [not detectable (ND) to 0.7], AsV 0.3 (ND to 0.5), MMAV 0.1 (ND to 0.2), and DMAV 0.7 (ND to 2.6). Samples from 301 people exposed to increased concentrations of arsenic in drinking water showed detectable AsIII in 99%, AsV in 98%, MMAV in 80%, and DMAV in 68% of samples. The mean (range) concentrations of arsenic species in these saliva samples were (in µg/L) AsIII 2.8 (0.1–38), AsV 8.1 (0.3–120), MMAV 0.8 (0.1–6.0), and DMAV 0.4 (0.1–3.9). Saliva arsenic correlated with drinking water arsenic. Odds ratios for skin lesions increased with saliva arsenic concentrations. The association between saliva arsenic concentrations and the prevalence of skin lesions was statistically significant (P <0.001).
Conclusions: Speciation of AsV, AsIII, MMAV, and DMAV in human saliva is a useful method for monitoring arsenic exposure.
Subscribe to:
Posts (Atom)