Identification of sudomotor activity in cutaneous sympathetic nerves using sweat expulsion as the effector response
In a warm environment at ambient temperatures between 25 degrees and 38 degrees C (relative humidity 50%-60%) the relationship between sympathetic activity in cutaneous nerves (SSA) and pulses of sweat expulsion was investigated in five young male subjects. The SSA was recorded from the peroneal nerve using a micro-electrode. Sweat expulsion was identified on the sweat rate records obtained from skin areas on the dorsal side of the foot, for spontaneous sweating and drug-induced sweating, using capacitance hygrometry. Sweat expulsion was always preceded by bursts of SSA with latencies of 2.4-3.0 s. This temporal relationship between bursts of SSA and sweat expulsion was noted not only in various degrees of thermal sweating but also in the sweating evoked by arousal stimuli, or by painful electric stimulation. The amplitude of the sudomotor burst was linearly related to the maximal rate of increase of the corresponding sweat expulsion, the amplitude of the expulsion and the integrated amount of sweat produced for the duration of the expulsion. The results provide direct evidence that sweat expulsion reflects directly centrally-derived sudomotor activity.
Available from: Dominik R Bach
- "linear) relationship between SSNA and SCR amplitude in the study by Bini et al. (1980). Results from yet another experiment are in keeping with this: The amplitude of SSNA bursts is linearly related to the maximal rate of sweat expulsion; and, somewhat more weakly, to the integrated sweat production during the skin response (Sugenoya et al., 1990). As a further argument to their claim, Henderson et al. (2012) discuss nerve stimulation studies. "
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Sympathetic arousal can be estimated from skin conductance responses (SCR).
Such estimation relies on estimation of skin sympathetic nerve activity (SSNA).
Physiological work has established a linear relationship of SCR and SSNA amplitudes.
NeuroImage 08/2013; 84(100). DOI:10.1016/j.neuroimage.2013.08.030 · 6.36 Impact Factor
Available from: ncbi.nlm.nih.gov
- "The EIS has been shown to have the capacity to predict the activity level of the sympathetic nervous system.20 This GRS device’s capacity for this has been reported in numerous studies,21,22 and can be explained by the hypothalamus response to the temperature change according to the sympathetic system activity, via the cholinergic fiber and sweat released. "
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ABSTRACT: Ten years of research and development have allowed an understanding of how the electro interstitial scan (EIS) works and what its clinical applications may be.
The EIS is a galvanic skin response device. The measurements are performed by electrical stimulation of the post sympathetic cholinergic fiber with weak DC current and voltage 1.28V applied during 2 minutes and in bipolar mode. CURRENT SCIENTIFIC KNOWLEDGE: EIS ELECTRICAL MEASUREMENTS ARE RELATED TO: (1) the concentration of free chloride ions in the interstitial fluid, which affects the transfer of electrical current and the ratio intensity/voltage; (2) the morphology of the interstitial fluid, which is related to the electrical dispersion calculated from the Cole equation (α parameter); (3) electrical stimulation, which causes a change in sweat rate at the passive electrodes - post sympathetic cholinergic fiber electrical stimulation appears to be responsible for activating M2 receptors, which regulate nitric oxide (NO) production in the endothelial cell and cause vasodilation and a released sweat response; and (4) the electrochemical redox reactions (electrolysis) of the released sweat on electrodes, which are different on the bulk of the metal electrodes (O2 + [4H(+)] + [4e(-)]) and on the Ag/AgCl disposable electrodes (AgCl precipitation).
FOR EACH OF THE EIS CLINICAL RESULTS, VARIOUS EXPLANATIONS WERE POSITED, SUCH AS: (1) electrical stimulation of the postsympathetic cholinergic fiber-activating NO production in the endothelial cell, which causes vasodilation and a released sweat response (diabetes detection); (2) estimation of interstitial fluid's acid-base balance, which is reflected in an electrochemical reaction on the bulk of the electrodes through the released sweat (prostate cancer detection); (3) estimation of cerebral interstitial fluid chloride ions (detection of ADHD in children); and (4) estimation of the morphology of the interstitial fluid (selective serotonin reuptake inhibitor treatment response).
After 10 years of development, the analysis of current scientific knowledge and results of clinical investigations have allowed a better understanding of EIS electrical measurements.
Medical Devices: Evidence and Research 03/2012; 5(1):23-30. DOI:10.2147/MDER.S29319
Available from: Maki Sato
- "Sweat expulsions were identified on the sweat rate curve according to the definition as fine waves with the shape of a rapid rise followed by a rather slow decline having a frequency of less than 30 min −1 or less and a duration of 5–10 s (Ogawa et al. 1972; Sugenoya and Ogawa 1985) (see Fig. 1). We counted sweat expulsions synchronous between both forearms as reflecting centrally derived sudomotor burst activity (Fig. 1), and their average rate was calculated as an indicator of central sudomotor activity since individual sweat expulsions are regarded to reflect sympathetic sudomotor burst activity (Bini et al. 1980; Sugenoya et al. 1990). "
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ABSTRACT: In summer and winter, young, sedentary male (N = 5) and female (N = 7) subjects were exposed to heat in a climate chamber in which ambient temperature (Ta) was raised continuously from 30 to 42°C at a rate of 0.1°C min(-1) at a relative humidity of 40%. Sweat rates (SR) were measured continuously on forearm, chest and forehead together with tympanic temperature (Tty), mean skin temperature (⁻Ts) and mean body temperature ⁻Tb. The rate of sweat expulsions (Fsw) was obtained as an indicator of central sudomotor activity. Tty and ⁻Tb were significantly lower during summer compared with winter in males; SR was not significantly different between summer and winter in males, but was significantly higher during summer in females; SR during winter was higher in males compared with females. The regression line relating Fsw to ⁻Tb shifted significantly from winter to summer in males and females, but the magnitude of the shift was not significantly different between the two subject groups. The regression line relating SR to Fsw was steepened significantly from winter to summer in males and females, and the change in the slope was significantly greater in females than in males. Females showed a lower slope in winter and a similar slope in summer compared to males. It was concluded that sweating function was improved during summer mediated by central sudomotor and sweat gland mechanisms in males and females, and, although the change of sweat gland function from winter to summer was greater in females as compared with males, the level of increased sweat gland function during summer was similar between the two subject groups.
International Journal of Biometeorology 03/2011; 55(2):203-12. DOI:10.1007/s00484-010-0325-1 · 3.25 Impact Factor
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