The effectiveness of the Uchida-Kraepelin test for psychological stress: an analysis of plasma and salivary stress substances
© Sugimoto et al. 2009
Received: 29 September 2008
Accepted: 03 April 2009
Published: 03 April 2009
The hypothalamic-pituitary-adrenocortical (HPA) axis and sympathetic adrenomedullary (SAM) system are the major stress-response pathways. Plasma adrenocorticotropic hormone (ACTH) represents HPA axis activity, while plasma catecholamines are used as markers of the SAM system. Salivary alpha amylase (AA), chromogranin A (CgA), and immunoglobulin A (IgA) are candidate markers of stress activation, although their role has not been established. The Uchida-Kraepelin (U-K) test is a questionnaire that requires intense concentration and effort, and has been used as a tool to induce mental stress. However, it is not clear whether or not the test is effective as a psychological/mental stressor.
In this study, normal young women took the U-K test and serial measurements of plasma ACTH and catecholamines (dopamine, noradrenaline, and adrenaline) (n = 10), as well as salivary AA, CgA, and IgA (n = 16) before, during and after the test.
We found no changes in any of these parameters at any time point during or after the U-K test.
Our findings indicate that the U-K test is not a suitable for measuring the psychological/mental stress of young women because the plasma data showed that it did not affect the HPA axis and SAM system. The U-K test should be employed carefully as a psychological/mental stressor due to insufficient scientific evidence of its effectiveness. In addition, salivary AA, CgA, and IgA should not simply be compared with previous reports, because the mechanism of secretion and normal range of each salivary parameter remain unknown. Salivary AA, CgA, and IgA may not be suitable candidate markers of psychological/mental stress.
The Uchida-Kraepelin (U-K) test is a questionnaire modified from the Kraepelin's arithmetic test, which was originally developed by Y. Uchida . The U-K test measures the ability of takers on task performance speed and task performance accuracy. The results of the U-K test provide an estimate of the individual's character. The U-K test requires focused effort and attention by the subject, making this test useful for the assessment not only of character but also of mental stress [2, 3]. In fact, it has been used widely to assess work aptitude as a mental stressor [2, 4–12]. However, it is not clear whether or not the U-K test per se provides psychological/mental stress to its taker.
Homovanillic acid (HVA) is a major metabolite of dopamine [11, 12], and 3-methoxy-4-hydroxyphenylglucol (MHPG) is a metabolite of noradrenaline ; both have been used as markers of stress incurred by the U-K test. However, serum catecholamines; dopamine (DA), noradrenaline (NA) and adrenaline (AD) have not been measured as stress markers, although excitement up-regulates these molecules, especially NA and AD, through the sympathetic nervous system [7, 13–16]. Likewise, the HPA axis marker adrenocorticotropic hormone (ACTH) has not been used as a marker of psychological/mental stress in a U-K test study, although the hypothalamic-pituitary-adrenocortical (HPA) axis is also known to be stimulated by various stressors [7, 15, 16].
Salivary fluid is often sampled for biological assays because of ease and noninvasive accessibility. Several salivary markers have been proposed as biological markers of psychological stress in humans, including salivary α-amylase (sAA) [2, 7, 17–24], salivary chromogranin A (sCgA) [25–29], and salivary immunoglobulin A (sIgA) [27, 30–36]. However, none are yet established as routine stress markers.
In the present study, we measured plasma ACTH, DA, NA and AD to investigate the effects of the U-K test applied as a psychological/mental stressor on the HPA axis and sympathetic adrenomedullary (SAM) system. We also examined the effects of the U-K test on sAA, sCgA, and sIgA secretion.
Participants and experimental design
The U-K test is a serial addition test, which requires takers to perform calculations as fast and accurately as possible within 30 min. This was achieved using pre-printed paper containing 15 lines of random, single-digit, horizontally aligned numbers. For each minute of the test, the subject was instructed to begin a new line regardless of their position on the current line. Each line contained an excess of calculations such that the subjects were not able to finish any line for a particular minute before being prompted to move on to the start of the next minute by the examiner's prompting. This test is usually performed for repeated 15 min of work and 5 min rest cycles.
To investigate the participants' character, the MOS 36-Item Short-Form Health Survey (SF-36)  was given to all participants before the U-K test. SF-36 version 2 includes scales for physical functioning, physical role, bodily pain, social functioning, general health perceptions, vitality, emotional role, and mental health. This SF-36 can be used to check health-related quality of life. Furthermore, the data of the U-K test of each participant was correlated with each character and with plasma and salivary stress substances. The character results obtained by the U-K test are composed of behavioral activation, mood or behavioral variation, behavioral sensitivity, character or behavioral deviation/tendency, and total typical/atypical manner.
The Ethics Committee of Tohoku Fukushi University approved the study protocol. The study was carried out in compliance with the Helsinki Declaration. All participants were fully briefed on the scope of the experiment, and informed consent with oral explanation and written documents was obtained from each participant prior to the study.
Measurements of plasma ACTH, dopamine, noradrenaline, and adrenaline levels
A cannula was inserted in a vein of the left arm and maintained via a heparin-saline lock system 3 h before undergoing the U-K test. Four ml of blood was collected over 5 min via the cannula immediately before, during, and at 0, 10, 30, and 60 min after the test. Plasma was prepared and assayed for ACTH by radioimmunoassay (RIA kit RK-001-01, Phoenix Pharmaceuticals Inc, Burlingame, CA), while DA, NA, and AD concentrations were estimated by high-performance liquid chromatography (HPLC).
Saliva collection and salivary flow rate calculation
Saliva was collected by the spitting method, which involves collecting spontaneous/passive drooling saliva, at baseline (at the start of the rest period), immediately before, during, and at 0, 5, 10, 20, 30, 40, 50, and 60 min after the test. Saliva was collected over 5 min and kept on ice. Samples were centrifuged at 1,500 × g for 15 min and the supernatant used for CgA and IgA measurements. The remainder was stored frozen at -80°C until further use. The amount of collected saliva in grams was converted to milliliters assuming that the specific gravity of saliva is 1.01 (g/ml); this value was divided by 5 to ascertain the salivary flow rate in ml/min.
Salivary α-amylase, chromogranin A, and immunoglobulin A assays
Amylase hydrolyzes the Gal-G2-CNP present in the reagent paper to produce a color change from white to yellow, measured optically for 30 sec. One unit of α-amylase activity (U) was defined as the enzymatic activity that could produce reduced sugar equivalent to 1 μmol maltose at 37°C in 1 min. Salivary AA was expressed in U/ml .
Salivary CgA and IgA were measured by enzyme immunoassay (EIA) using the YKO human chromogranin A EIA kit (Yanaihara Institute Inc®) and salivary secretory IgA indirect enzyme immunoassay kit (Salimetrics LLC Inc, State College, Pennsylvania, USA). This IgA kit measured salivary IgA within the range of 379.39 ± 261.47 μg/ml, (mean ± SD, n = 21).
Data are expressed as mean ± SD. All data were analyzed by one-way analysis of variance (ANOVA) followed by Tukey's test. Sample numbers are 10 for blood samples and 16 for salivary samples. A P value less than 0.05 denoted the presence of a statistically significant difference.
The U-K test does not influence plasma ACTH concentration
The U-K test does not influence plasma noradrenaline, dopamine, and adrenaline concentrations
To examine the effect of the U-K test on the SAM system, plasma levels of NA, DA, and AD. Plasma NA, DA, and AD concentrations measured before, during, and after the U-K test are shown in Figure [2B and 2C]. There were no significant changes from the standard range of each catecholamine in NA, DA, and AD values during or after U-K test. Plasma NA: [df = 5, F-value = 0.27, P = 0.93]. Plasma DA: [df = 5, F-value = 1, P = 0.43]. Plasma AD: [df = 5, F-value = 0.66, P = 0.65].
The U-K test does not influence salivary flow rate
The U-K test does not influence salivary α-amylase activity, chromogranin A or immunoglobulin A
Psychological assessment of participants and the relationship between their character and stress substances
The psychological status of each participant was assessed by the analysis of SF-36 and the U-K test. No remarkable psychological patterns or character deviation were noted for the participants. None of the categories of the SF-36 or U-K test was correlated with plasma ACTH, DA, NA, or AD concentration or with salivary AA, CgA, or AA (data not shown).
The U-K test given to the young women studied induced no significant changes in any of the reported markers of psychological/mental stress, i.e., plasma ACTH and catecholamines. In general, ACTH is up-regulated through the HPA axis under stress conditions, often accompanied by secretion of AD and NA from the adrenal medulla and sympathetic nerve terminals [7, 13–16]. In fact, the Trier Social Stress Test (TSST) induced up-regulation of plasma ACTH until 30–40 min after the stress [42, 43], although plasma DA, NA and AD have not been measured as stress markers. Therefore, it seems that the U-K test did not affect the HPA and/or SAM system of the participants of our study. Dickerson and Kemeny  described that though acute psychological stressors can elicit cortisol and ACTH activation, not all acute psychological stressors provoke this system. There is a substantial degree of variability in the size of cortisol and ACTH effects, depending on the characteristics of the stressor. Our results do not contradict the study of Dickerson and Kemeny . The U-K test may have borderline value as a stress task because they categorized the U-K test as a cognitive task in which cortisol has little effect. In this study, there may be problem in that our experiment was done with a limited population of young women. However, Takai et al.  recently investigated gender differences in the activities of the HPA and SAM systems in response to acute psychological stress. They found no gender differences in the resting salivary cortisol and amylase levels. Furthermore, there were no gender differences in the salivary amylase level after stressful video viewing. Taken together, we do not recommend the use of the U-K test, at least for young women, for inducing psychological/mental stress, despite many reports of such an application [2, 4–12].
The mean salivary flow rate of our participants was 0.33 ± 0.41 ml/min by the passive spitting method. This rate is consistent with that reported in previous studies [20–22, 24, 33, 44]. In this study, we used the spitting method for saliva collection in preference to salivettes® cotton (Sarstedt, Numbrecht, Germany) to avoid mechanical stimulation of salivary secretion. One recent study compared the two methods and found no difference in mean saliva volume collected . In contrast, another study showed that the relative increases in flow rate induced by psychological stress were significantly higher in saliva obtained by the spitting method than in that collected using salivettes cotton, although the saliva flow rate was not significantly different between the two methods under non-stress conditions . Moreover, the cotton method caused substantial interference to many biomarker assays, including sIgA, giving falsely low readings due to the absorbent materials [45, 46]. We therefore chose not to use the salivettes cotton method, and followed an earlier recommendation to use the spitting method for both unstimulated and stimulated whole saliva collection . After all, the flow rates were not altered by the U-K test, arguing against any stress effect of the test on sAA, sCgA, or sIgA secretion.
No changes in salivary AA, CgA, and IgA concentrations were induced before during and after the U-K test. Goi et al.  studied the effect of the U-K test on salivary flow rate, sIgA, and sAA at short time points; 30 min and immediately prior to the test, as well as immediately and 30 min after the test. Only salivary flow rate 30 min after the U-K test and sIgA immediately after were increased over the 30-min-prior readings. The above study had a different methodology than ours; the authors used cotton for salivary collection with rough time points and a quantitative kinetic method to assay sAA.
Values and methods from previous reports for the determination of representative salivary stress markers during a non-stress period
Salivary stress marker
Salivary collection method
39.1 – 309.1*
15 – 365 (14 – 16 PM)
60 – 200
30 – 60
20 – 230
40 – 150
9 – 50
0 – 27
male 63.6 – 179.4
female 81.1 – 183.1
7.8 – 76.6
290 – 700
21.2 – 149.8
males 50.9 – 192.1
females 58.2 – 190.3
0 – 50
2.6 – 65.0
9.5 – 43.4
6.9 – 82.2
0.2 – 0.4
1.2 – 2.4
3.6 – 13.4
4.65 – 15.05
28.7 – 92.7
7.6 – 132.4
6.4 – 17.7 (PM sampling)
9 – 11
186.7 – 653.4
38.7 – 79.3
61.7 – 107.5
0 – 100.62
114.12 – 238.78
91.2 – 148.3
117.92 – 640.86
103.2 – 286.6
CgA is a major soluble protein in adrenal chromaffin cells and adrenergic neurons. It belongs to a family of highly acidic proteins, the chromogranins, which are co-stored and co-released with AD and NA in the adrenal medulla , and secreted with the catecholamines into the circulation . Moreover, CgA is a valuable indicator of SAM activity . Human CgA is produced by the submandibular glands and secreted into saliva . Salivary CgA is considered a marker of sympathetic nervous activity including the SAM system . Table 1 also lists the reported sCgA levels measured at rest or before stress. Our sCgA values measured during the non-stress periods were higher than those reported in two previous studies, and this difference could be due to the use of different collection methods. Moreover, the secretory pattern of sCgA follows circadian rhythms . Like sAA, a normal range for human sCgA also remains to be specified.
Salivary IgA is a convenient and commonly used indicator of immune status. This parameter reportedly indicates the functional status of the entire mucosal immune system . Numerous studies have shown that sIgA is sensitive to psychological variables. Early studies explored the relationship between sIgA and long-term psychological stress or in individuals particularly prone to stress . Such studies consistently revealed stress-related down-regulation of sIgA . This evidence supports the argument that prolonged psychological stress can compromise certain aspects of immune function . Paradoxically, acute responses to a psychological challenge include a rise in sIgA concentration . This mobilization of sIgA has also been reported in response to acute laboratory psychological stress tests including mental arithmetic tests [35, 41]. However, there is little information on whether or not sIgA secretion is affected by psychological stress, or how that might occur mechanistically. An association was demonstrated between psychological activation of the HPA axis and the modulation of sIgA [59, 60]. However, these studies showed opposite correlations of salivary cortical and sIgA response. Moreover, the non-stress sIgA values varied between studies (Table 1) [61–66]. Our results were compatible with the expected range reported in the kit instructions, making our sIgA data more reliable.
Salivary IgA is produced by plasma cells located adjacent to the salivary gland ducts and acini . The sIgA response to oral antigens may be induced via two mechanisms: stimulation of the response directly following the proliferation and differentiation of local lymphoid cells, and the migration of antigen-sensitized IgA precursor B cells from gut-associated lymphoid tissue to salivary glands  (and references therein). Further investigations of the association between sIgA and the stress response as well as the mechanisms involved are clearly needed.
Many scientists have used the U-K test as a psychological/mental stressor. Our results indicate, however, that the U-K test should be employed carefully as a psychological/mental stressor due to insufficient scientific evidence of its effectiveness. In addition, salivary AA, CgA, and IgA are probably not suitable candidate markers of psychological/mental stress, because the mechanism of stress-induced secretion and their normal ranges remain to be specified.
The U-K test has been regarded as a psychological/mental stress inducer. We measured the serial changes in plasma ACTH, DA, NA, and AD levels, as well as salivary AA, CgA, and IgA concentrations before, during and after conducting a U-K test. None of these stress substances changed in response to the test, suggesting that it does not elicit the HPA axis and/or SAM system stress response. Therefore, the U-K test does not seem to be an appropriate psychological/mental stressor. In addition, salivary AA, CgA, and IgA should not simply be compared with previous reports, because the mechanism of secretion and normal range of each salivary parameter remain unknown. Salivary AA, CgA, and IgA may not be suitable candidate markers of psychological/mental stress. Since the present experiment was done only with young women, further studies of other populations are necessary.
We greatly appreciate the participation of the volunteers in this study. We also thank Dr. Eriko Kasahara for her support during the course of the study.
This work was carried out at the Kansei Fukushi Research Center of Tohoku Fukushi University, Sendai, Japan. Funding for this study was provided by the "Academic Frontiers" Project for Private Universities: a matching fund subsidy from the Ministry of Education, Culture, Sports, Science and Technology of Japan (2004–2008), and was also supported by Research Grants for Scientific Research (C) 18592066 and (C) 19592401 from the Ministry of Education, Culture, Sports, Science and Technology (2006–2008). These grants had no further role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication.
- Kashiwagi S, Yanai H, Aoki T, Tamai H, Tanaka Y, Hokugoh K: A factor analytic study of the items for the personality description based on the principle of the three traits theory for the work curve of addition of the Uchida-Kraepelin psychodiagnostic test. Shinrigaku Kenkyu (The Japanese journal of psychology) 1985, 56:179–182. (in Japanese)
- Goi N, Hirai Y, Harada H, Ikari A, Ono T, Kinae N, Hiramatsu M, Nakamura K, Takagi K: Comparison of peroxidase response to mental arithmetic stress in saliva of smokers and non-smokers. J Toxicol Sci 2007, 32:121–127.View ArticlePubMed
- Li GY, Ueki H, Kawashima T, Sugataka K, Muraoka T, Yamada S: Involvement of the noradrenergic system in performance on a continuous task requiring effortful attention. Neuropsychobiology 2004, 50:336–340.View ArticlePubMed
- Negoescu R, Dinca-Panaitescu S, Filcescu V, Ionescu D, Wolf S: Mental stress enhances the sympathetic fraction of QT variability in an RR-independent way. Integr Physiol Behav Sci 1997, 32:220–227.View ArticlePubMed
- Dinca-Panaitescu S, Dinca-Panaitescu M, Achim A, Negoescu R: Idioventricular low frequency oscillation in QT interval responds univocally to RR confusing kinds of mental stress. Integr Physiol Behav Sci 1999, 34:10–18.View ArticlePubMed
- Oishi K, Kamimura M, Nigorikawa T, Nakamiya T, Williams RE, Horvath SM: Individual differences in physiological responses and type A behavior pattern. Appl Human Sci 1999, 18:101–108.View ArticlePubMed
- Yamaguchi M, Kanemori T, Kanemaru M, Takai N, Mizuno Y, Yoshida H: Performance evaluation of salivary amylase activity monitor. Biosens Bioelectron 2004, 20:491–497.View ArticlePubMed
- Shimbo M, Kuroiwa C, Yokogoshi H: The effects of carbohydrate consumption on stress levels in humans. J Nutr Sci Vitamino 2004, 50:283–285.
- Strelets VB, Garakh Zh V, Novototskii-Vlasov V: Comparative study of the gamma-rhythm in the norm, pre-examination stress and patients with the first depressive episode. Zh Vyssh Nerv Deiat Im I P Pavlova 2006, 56:219–227.PubMed
- Yasumasu T, Reyes Del Paso GA, Takahara K, Nakashima Y: Reduced baroreflex cardiac sensitivity predicts increased cognitive performance. Psychophysiology 2006, 43:41–45.View ArticlePubMed
- Sumiyoshi T, Saitoh O, Yotsutsuji T, Itoh H, Kurokawa K, Kurachi M: Differential effects of mental stress on plasma homovanillic acid in schizophrenia and normal controls. Neuropsychopharmacology 1999, 20:365–369.View ArticlePubMed
- Sumiyoshi T, Yotsutsuji T, Kurachi M, Itoh H, Kurokawa K, Saitoh O: Effect of mental stress on plasma homovanillic acid in healthy human subjects. Neuropsychopharmacology 1998, 19:70–73.View ArticlePubMed
- Johnson EO, Kamilaris TC, Chrousos GP, Gold PW: Mechanisms of stress: a dynamic overview of hormonal and behavioral homeostasis. Neurosci Biobehav Rev 1992, 16:115–30.View ArticlePubMed
- Habib KE, Gold PW, Chrousos GP: Neuroendocrinology of stress. Endocrinol Metab Clin North Am 2001, 30:695–728.View ArticlePubMed
- Black PH, Garbutt LD: Stress, inflammation and cardiovascular disease. J Psychosom Res 2002, 52:1–23.View ArticlePubMed
- Takai N, Yamaguchi M, Aragaki T, Eto K, Uchihashi K, Nishikawa Y: Gender-specific differences in salivary biomarker responses to acute psychological stress. Ann N Y Acad Sci 2007, 1098:510–515.View ArticlePubMed
- Nater UM, Rohleder N, Schlotz W, Ehlert U, Kirschbaum C: Determinants of the diurnal course of salivary alpha-amylase. Psychoneuroendocrinology 2007, 32:392–401.View ArticlePubMed
- Chatterton RT Jr, Vogelsong KM, Lu YC, Ellman AB, Hudgens GA: Salivary alpha-amylase as a measure of endogenous adrenergic activity. Clin Physiol 1996, 16:433–448.View ArticlePubMed
- Skosnik PD, Chatterton RT Jr, Swisher T, Park S: Modulation of attentional inhibition by norepinephrine and cortisol after psychological stress. Int J Psychophysiol 2000, 36:59–68.View ArticlePubMed
- Li TL, Gleeson M: The effect of single and repeated bouts of prolonged cycling and circadian variation on saliva flow rate, immunoglobulin A and alpha-amylase responses. J Sports Sci 2004, 22:1015–1024.View ArticlePubMed
- Gordis EB, Granger DA, Susman EJ, Trickett PK: Asymmetry between salivary cortisol and alpha-amylase reactivity to stress: relation to aggressive behavior in adolescents. Psychoneuroendocrinology 2006, 31:976–87.View ArticlePubMed
- Rohleder N, Wolf JM, Maldonado EF, Kirschbaum C: The psychosocial stress-induced increase in salivary alpha-amylase is independent of saliva flow rate. Psychophysiology 2006, 43:645–652.View ArticlePubMed
- Granger DA, Kivlighan KT, el-Sheikh M, Gordis EB, Stroud LR: Salivary alpha-amylase in biobehavioral research: recent developments and applications. Ann N Y Acad Sci 2007, 1098:122–144.View ArticlePubMed
- Takai N, Yamaguchi M, Aragaki T, Eto K, Uchihashi K, Nishikawa Y: Effect of psychological stress on the salivary cortisol and amylase levels in healthy young adults. Arch Oral Biol 2004, 49:963–968.View ArticlePubMed
- Lee T, Shimizu T, Iijima M, Obinata K, Yamashiro Y, Nagasawa S: Evaluation of psychosomatic stress in children by measuring salivary chromogranin A. Acta Paediatr 2006, 95:935–939.View ArticlePubMed
- Noto Y, Sato T, Kudo M, Kurata K, Hirota K: The relationship between salivary biomarkers and state-trait anxiety inventory score under mental arithmetic stress: a pilot study. Anesth Analg 2005, 101:1873–1876.View ArticlePubMed
- Ng V, Koh D, Mok BY, Chia SE, Lim LP: Salivary biomarkers associated with academic assessment stress among dental undergraduates. J Dent Educ 2003, 67:1091–1094.PubMed
- Miyakawa M, Matsui T, Kishikawa H, Murayama R, Uchiyama I, Itoh T, Yoshida T: Salivary chromogranin A as a measure of stress response to noise. Noise Health 2006, 8:108–113.View ArticlePubMed
- Kanamaru Y, Kikukawa A, Shimamura K: Salivary chromogranin-A as a marker of psychological stress during a cognitive test battery in humans. Stress 2006, 9:127–131.View ArticlePubMed
- Lowe G, Urquhart J, Greenman J, Lowe G: Academic stress and secretory immunoglobulin A. Psychol Rep 2000, 87:721–722.View ArticlePubMed
- Hucklebridge F, Lambert S, Clow A, Warburton DM, Evans PD, Sherwood N: Modulation of secretory immunoglobulin A in saliva; response to manipulation of mood. Biol Psychol 2000, 53:25–35.View ArticlePubMed
- Deinzer R, Kleineidam C, Stiller-Winkler R, Idel H, Bachg D: Prolonged reduction of salivary immunoglobulin A (sIgA) after a major academic exam. Int J Psychophysiol 2000, 37:219–232.View ArticlePubMed
- Miletic ID, Schiffman SS, Miletic VD, Sattely-Miller EA: Salivary IgA secretion rate in young and elderly persons. Physiol Behav 1996, 60:243–248.View ArticlePubMed
- Otsuki T, Sakaguchi H, Hatayama T, Takata A, Hyodoh F, Tsujita S, Ueki A, Morimoto K: Secretory IgA in saliva and academic stress. Int J Immunopathol Pharmacol. 2004,17(Suppl 2):45–48.PubMed
- Willemsen G, Ring C, McKeever S, Carroll D: Secretory immunoglobulin A and cardiovascular activity during mental arithmetic: effects of task difficulty and task order. Biol Psychol 2000, 52:127–141.View ArticlePubMed
- Ohira H: Social support and salivary secretory immunoglobulin A response in women to stress of making a public speech. Percept Mot Skills 2004, 98:1241–1250.PubMed
- Fukuhara S, Suzukamo Y: SF-36v2™ (Japanese version) Tokyo: iHope International 2004.
- Yamaguchi M, Deguchi M, Wakasugi J, Ono S, Takai N, Higashi T, Mizuno Y: Hand-held monitor of sympathetic nervous system using salivary amylase activity and its validation by driver fatigue assessment. Biosens Bioelectron 2006, 21:1007–1014.View ArticlePubMed
- Dickerson SS, Kemeny ME: Acute stressors and cortisol responses: a theoretical integration and synthesis of laboratory research. Psychol Bull 2004, 130:355–391.View ArticlePubMed
- Ferguson DB: The flow rate and composition of human labial gland saliva. Arch Oral Biol 1999,44(Suppl 1):S11–14.View ArticlePubMed
- Willemsen G, Ring C, Carroll D, Evans P, Clow A, Hucklebridge F: Secretory immunoglobulin A and cardiovascular reactions to mental arithmetic and cold pressor. Psychophysiology 1998, 35:252–259.View ArticlePubMed
- Kudielka BM, Schommer NC, Hellhammer DH, Kirschbaum C: Acute HPA axis responses, heart rate, and mood changes to psychosocial stress (TSST) in humans at different times of day. Psychoneuroendocrinology 2004, 29:983–992.View ArticlePubMed
- Kirschbaum C, Pirke KM, Hellhammer DH: The 'Trier Social Stress Test' – a tool for investigating psychobiological stress responses in a laboratory setting. Neuropsychobiology 1993, 28:76–81.View ArticlePubMed
- Nicolau J, Leite MF: In vitro and in vivo effects of fluoride solutions on human salivary amylase. Fluoride 2001, 34:55–60.
- Michishige F, Kanno K, Yoshinaga S, Hinode D, Takehisa Y, Yasuoka S: Effect of saliva collection method on the concentration of protein components in saliva. J Med Invest 2006, 53:140–146.View ArticlePubMed
- Shirtcliff EA, Granger DA, Schwartz E, Curran MJ: Use of salivary biomarkers in biobehavioral research: cotton-based sample collection methods can interfere with salivary immunoassay results. Psychoneuroendocrinology 2001, 26:165–173.View ArticlePubMed
- Navazesh M: Methods for collecting saliva. Ann N Y Acad Sci 1993, 694:72–77.View ArticlePubMed
- van Stegeren A, Rohleder N, Everaerd W, Wolf OT: Salivary alpha amylase as marker for adrenergic activity during stress: effect of beta blockade. Psychoneuroendocrinology 2006, 31:137–141.View ArticlePubMed
- Blaschko H, Comline RS, Schneider FH, Silver M, Smith AD: Secretion of a chromaffin granule protein, chromogranin, from the adrenal gland after splanchnic stimulation. Nature 1967, 215:58–59.View ArticlePubMed
- Winkler H, Fischer-Colbrie R: The chromogranins A and B: the first 25 years and future perspectives. Neuroscience 1992, 49:497–528.View ArticlePubMed
- Taupenot L, Harper KL, O'Connor DT: The chromogranin-secretogranin family. N Engl J Med 2003, 348:1134–1149.View ArticlePubMed
- Saruta J, Tsukinoki K, Sasaguri K, Ishii H, Yasuda M, Osamura YR, Watanabe Y, Sato S: Expression and localization of chromogranin A gene and protein in human submandibular gland. Cells Tissues Organs 2005, 180:237–244.View ArticlePubMed
- Nakane H, Asami O, Yamada Y, Harada T, Matsui N, Kanno T, Yanaihara N: Salivary chromogranin A as an index of psychosomatic stress response. Biomed Res 1998, 19:401–406.
- Den R, Toda M, Nagasawa S, Kitamura K, Morimoto K: Circadian rhythm of human salivary chromogranin A. Biomed Res 2007, 28:57–60.View ArticlePubMed
- Mestecky J: Saliva as a manifestation of the common mucosal immune system. Ann N Y Acad Sci 1993, 694:184–194.View ArticlePubMed
- Hucklebridge F, Clow A, Evans P: The relationship between salivary secretory immunoglobulin A and cortisol: neuroendocrine response to awakening and the diurnal cycle. Int J Psychophysiol 1998, 31:69–76.View ArticlePubMed
- Evans P, Hucklebridge FH, Clow A, Doyle A: Secretory immunoglobulin A as a convenient biomarker in health survey work. Health psychology and quality of life research (Edited by: Rodrigues M). Spain: Health Psychology Dept., University of Alicante 1995, 541–549.
- Evans P, Clow A, Hucklebridge FH: Stress and the immune system: current issues and directions in research. Psychologist 1997, 10:303–307.
- Zeier H, Brauchli P, Joller-Jemelka HI: Effects of work demands on immunoglobulin A and cortisol in air traffic controllers. Biol Psychol 1996, 42:413–423.View ArticlePubMed
- Evans P, Bristow M, Hucklebridge F, Clow A, Pang FY: Stress, arousal, cortisol and secretory immunoglobulin A in students undergoing assessment. Br J Clin Psychol 1994, 33:575–576.PubMed
- Rohleder N, Nater UM, Wolf JM, Ehlert U, Kirschbaum C: Psychosocial stress-induced activation of salivary alpha-amylase: an indicator of sympathetic activity? Ann N Y Acad Sci 2004, 1032:258–263.View ArticlePubMed
- Nater UM, Rohleder N, Gaab J, Berger S, Jud A, Kirschbaum C, Ehlert U: Human salivary alpha-amylase reactivity in a psychosocial stress paradigm. Int J Psychophysiol 2005, 55:333–342.View ArticlePubMed
- Ehlert U, Erni K, Hebisch G, Nater U: Salivary alpha-amylase levels after yohimbine challenge in healthy men. J Clin Endocrinol Metab 2006, 91:5130–5133.View ArticlePubMed
- Toda M, Kusakabe S, Nagasawa S, Kitamura K, Morimoto K: Effect of laughter on salivary endocrinological stress marker chromogranin A. Biomed Res 2007, 28:115–118.View ArticlePubMed
- Clow A, Lambert S, Evans P, Hucklebridge F, Higuchi K: An investigation into asymmetrical cortical regulation of salivary S-IgA in conscious man using transcranial magnetic stimulation. Int J Psychophysiol 2003, 47:57–64.View ArticlePubMed
- Tsuboi H, Hamer M, Tanaka G, Takagi K, Kinae N, Steptoe A: Responses of ultra-weak chemiluminescence and secretory IgA in saliva to the induction of angry and depressive moods. Brain Behav Immun 2008, 22:209–214.View ArticlePubMed
- Marcotte H, Lavoie MC: Oral microbial ecology and the role of salivary immunoglobulin A. Microbiol Mol Biol Rev 1998, 62:71–109.PubMed
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