Alpha-amylase
Alpha-amylase is a hormone that regulates the autonomic nervous system (sympathetic/parasympathetic nervous system). Its importance for the autonomic nervous system corresponds to that of cortisol for the HPA axis.
The alpha-amylase level correlates with the changes in the cortisol level.1
α-Amylase is secreted from the parotid gland (glandula parotidea, glandula parotis or parotid gland) during adrenergic activity. α-Amylase is a marker for stress-induced adrenergic activity2 and for mean arterial pressure (MAP). Mean arterial pressure is the product of cardiac output and total peripheral resistance, which reflects organ perfusion. It is a physiological measure of the activation of the sympathetic nervous system.3
α-Amylase increases faster than salivary cortisol during psychosocial stress.4 It is possible that only salivary amylase, but not blood alpha-amylase levels, are elevated in response to an acute stressor, while blood and salivary amylase levels react in parallel to pharmacological treatment. These differences do not exist for cortisol.
The alpha-amylase stress response is significantly increased in subjects with childhood trauma.5
Of 62 ADHD-I affected children, the ADHD-HI type showed identical cortisol levels to non-affected children before venipuncture, while the ADHD-I subtype showed elevated cortisol levels compared to non-affected children even before venipuncture. Since basal cortisol levels are lower in both ADHD-I and ADHD-HI sufferers than in non-affected individuals, this could be an anxiety response in anticipation of the stressor.1 The same pattern was seen in relation to alpha-amylase as a representative of the autonomic nervous system.
Prolonged treatment with stimulants reduces cortisol and alpha-amylase levels in ADHD sufferers.6
The basal alpha-amylase profile corresponds to that of cortisol.
In boys with externalizing problems, the basal cortisol level also corresponds to the typical (decreasing) course of the day, although this sometimes starts from a lower morning level. Oppositional defiant behavior (ODD) or ADHD, on the other hand, do not influence the daily cortisol levels.7
However, externalizing behavioural disorders in boys correlated with significantly reduced alpha-amylase levels.7
Subjects with a COMT Val158Val or a Met158Met gene polymorphism showed lower alpha-amylase levels than subjects with a COMT Val158Met gene polymorphism.7
Angeli, Korpa, Johnson, Apostolakou, Papassotiriou, Chrousos, Pervanidou (2018):Salivary cortisol and alpha-amylase diurnal profiles and stress reactivity in children with Attention Deficit Hyperactivity Disorder. Psychoneuroendocrinology. 2018 Apr;90:174-181. doi: 10.1016/j.psyneuen.2018.02.026. ↥ ↥
van Stegeren, Rohleder, Everaerd, Wolf (2006): Salivary alpha amylase as marker for adrenergic activity during stress: effect of betablockade. Psychoneuroendocrinology. 2006 Jan;31(1):137-41. doi: 10.1016/j.psyneuen.2005.05.012. PMID: 16046076. ↥
Bloomfield, McCutcheon, Kempton, Freeman, Howes (2019): The effects of psychosocial stress on dopaminergic function and the acute stress response. Elife. 2019 Nov 12;8:e46797. doi: 10.7554/eLife.46797. PMID: 31711569; PMCID: PMC6850765. ↥
Maruyama, Kawano, Okamoto, Ando, Ishitobi, Tanaka, Inoue, Imanaga, Kanehisa, Higuma, Ninomiya, Tsuru, Hanada, Akiyoshi (2012): Differences in salivary alpha-amylase and cortisol responsiveness following exposure to electrical stimulation versus the Trier Social Stress Tests. PLoS One. 2012;7(7):e39375. doi: 10.1371/journal.pone.0039375. PMID: 22859941; PMCID: PMC3408464. ↥
Kuras, McInnis, Thoma, Chen, Hanlin, Gianferante, Rohleder (2016): Increased alpha-amylase response to an acute psychosocial stress challenge in healthy adults with childhood adversity. Dev Psychobiol. 2017 Jan;59(1):91-98. doi: 10.1002/dev.21470. ↥
Ertugrul, Kirzioglu, Aktepe, Savas (2018): The effects of psychostimulants on oral health and saliva in children with attention deficit hyperactivity disorder: A case-control study. Niger J Clin Pract. 2018 Sep;21(9):1213-1220. doi: 10.4103/njcp.njcp_385_17. ↥
Angyal, Halasz, Meszaros, Kovacs, Kruk, Nemoda (2016): Potential salivary biomarkers and their genetic effects in a pilot study of adolescent boys with externalizing problems. Neuropsychopharmacol Hung. 2016 Dec;18(4):173-179. ↥ ↥ ↥