The Spit Report -- Salimetrics

Volume 5, Issue 1, January 2012 - Salimetrics


(sAA, CgA, VIP, NPY)

Many studies in the behavioral and developmental sciences now utilize a multiple-biomarker approach. For example, salivary cortisol and salivary alpha-amylase (sAA) are often measured together as markers of activity in the hypothalamic-pituitary-adrenal axis (HPAA) and autonomic nervous system (ANS), respectively. Since these two systems are physiologically linked as part of the larger stress response system, measuring both biomarkers together should help researchers as they try to understand the ways that the two systems interact, and, ultimately, how these interactions are related to human health and development. (Bauer, et al. 2002; Gordis, et al. 2006; El-Sheikh, et al. 2008)

Collecting with the Salimetrics Children's Swab

In order to probe the relationships between components of the stress system, bio-behavioral researchers often observe the reactivity of biomarkers such as cortisol and sAA to standardized laboratory stressors that include various physical, mental, and social components. In view of the complex and varied nature of the ANS response to stress, (Caccioppo, 1994; Cacioppo et al.,1998) it seems likely that researchers could benefit from the use of additional and/or more specific measures of ANS activity in their studies. Because saliva has been widely adopted as a non-invasive, practical testing medium that allows collection of biological samples in a wide range of settings, there is currently interest in determining whether additional autonomic markers can be identified in saliva.

The belief that additional ANS markers will be found in saliva is bolstered by the knowledge that both the composition and flow of saliva from the major human salivary glands are controlled by dual innervation from the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). Saliva flow is largely controlled by the PNS and its main neurotransmitter acetylcholine (ACh), which binds to muscarinic receptors on the salivary cells. (Proctor & Carpenter, 2007) As the flow of saliva increases, changes in its ionic composition and pH also occur. (Catalán et al., 2009; Neyraud et al., 2009; Dawes & Jenkins, 1964; Dawes, 2008) Secretion of salivary proteins is largely controlled by the SNS through release of noradrenaline (NAd), which binds to adrenergic receptors on the salivary cells. The PNS also controls some protein secretion either by itself (mucins from mucous cells), or in conjunction with the SNS (proteins from serous cells). (Proctor & Carpenter, 2007) Additionally, sympathetic and parasympathetic nerves release a number of non-adrenergic, non-cholinergic (NANC) peptide transmitters such as vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), which also help regulate saliva flow and composition. (Ekström, 1999)

If changes related to the PNS (e.g., saliva flow rates, pH, neuropeptides associated with PNS) can be separated from those related to the SNS (e.g., secretion of serous proteins, neuropeptides associated with SNS), then it may be possible to gain useful information about activity in both systems through a common saliva sample. Although additional research needs to be carried out to explore candidate analytes, our initial attention is focused on seven markers related to ANS activity that can be measured in saliva: sAA, chromogranin A (CgA), VIP, NPY, saliva flow rate, and saliva pH.

In this issue of the Spit Report we feature three articles that involve examples of salivary proteins that are currently under consideration as biomarkers related to autonomic nervous activity: chromogranin A, and the neuropeptides VIP and NPY.

Refrences >

For additional background information on proteins and peptides in saliva or chemical changes in saliva that result from stimulated flow, please click on the links below:

Neuropeptides >

General Information on Salivary Proteins >

Chromogranin A >

Saliva Flow, Ionic Strength, and pH >



Collecting and Handling Saliva for Analysis of Novel Protein and Peptide Markers

Information on the best methods to collect and handle saliva samples for the analysis of novel protein and peptide markers of ANS activity is limited. We therefore recommend a conservative approach.

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