Thermoregulatory Thresholds for Vasoconstriction in Patients Anesthetized with Various 1-Minimum Alveolar Concentration Combinations of Xenon, Nitrous Oxide, and Isoflurane 

1999 ◽  
Vol 91 (3) ◽  
pp. 626-626 ◽  
Author(s):  
Takahisa Goto ◽  
Takashi Matsukawa ◽  
Daniel I. Sessler ◽  
Shoichi Uezono ◽  
Yoshiki Ishiguro ◽  
...  
Keyword(s):  
Nervous System ◽  
Nitrous Oxide ◽  
Minimum Alveolar Concentration ◽  
Demographic Variables ◽  
Temperature Gradients ◽  
Temperature Threshold ◽  
Sympathetic Activation ◽  
Isoflurane Anesthesia ◽  
The Core ◽  
Sympathetic Nervous

Background Nitrous oxide limits intraoperative hypothermia because the vasoconstriction threshold with nitrous oxide is higher than with equi-minimum alveolar concentrations of sevoflurane or isoflurane, presumably because of its stimulating actions on the sympathetic nervous system. Xenon, in contrast, does not cause sympathetic activation. Therefore, the authors tested the hypothesis that the vasoconstriction threshold during xenon-isoflurane anesthesia is less than during nitrous oxide-isoflurane anesthesia or isoflurane alone. Methods Fifteen patients each were randomly assigned to one of three 1-minimum alveolar concentration anesthetic regimens: (1) xenon, 43% (0.6 minimum alveolar concentration) and isoflurane, 0.5% (0.4 minimum alveolar concentration); (2) nitrous oxide, 63% (0.6 minimum alveolar concentration) and isoflurane 0.5%; or (3) isoflurane, 1.2%. Ambient temperature was maintained near 23 degrees C and the patients were not actively warmed. Thermoregulatory vasoconstriction was evaluated using forearm-minus-fingertip skin temperature gradients. A gradient exceeding 0 degrees C indicated significant vasoconstriction. The core-temperature threshold that would have been observed if skin had been maintained at 33 degrees C was calculated from mean skin and distal esophageal temperatures at the time of vasoconstriction. Results The patients' demographic variables, preinduction core temperatures, ambient operating room temperatures, and fluid balance were comparable among the three groups. Heart rates were significantly less during xenon anesthesia than with nitrous oxide. The calculated vasoconstriction threshold was lowest with xenon (34.6+/-0.8 degrees C, mean +/- SD), intermediate with isoflurane alone (35.1+/-0.6 degrees C), and highest with nitrous oxide (35.7+/-0.6 degrees C). Each of the thresholds differed significantly. Conclusions Xenon inhibits thermoregulatory control more than isoflurane, whereas nitrous oxide is the least effective in this respect.

Presynaptic modulation of evoked NE release contributes to sympathetic activation after pressure overload

2004 ◽  
Vol 286 (6) ◽  
pp. H2151-H2158 ◽  
Author(s):  
Wendell S. Akers ◽  
Lisa A. Cassis
Keyword(s):  
Heart Failure ◽  
Nervous System ◽  
Left Ventricle ◽  
Sympathetic Nervous System ◽  
Pressure Overload ◽  
Ang Ii ◽  
Sympathetic Activation ◽  
Presynaptic Modulation ◽  
Uk 14,304 ◽  
Sympathetic Nervous

Activation of the sympathetic nervous system is well documented in heart failure. Our previous studies demonstrated an increase in evoked norepinephrine (NE) release from left ventricle (LV) slices at 10 days of pressure overload. The purpose of this study was to test the hypothesis that presynaptic modulation of NE release contributes to sympathetic activation after pressure overload. We examined the functional status of the presynaptic α2- and β2-receptors and ANG II subtype 1 (AT1) receptors in LV slices from 10-day aortic constricted (AC) and sham-operated (SO) rats. Evoked 3H overflow from LV slices preloaded with [3H]NE was increased in AC rats. The α2-agonist UK-14,304 decreased evoked 3H overflow with no differences between groups. The β2-agonist salbutamol increased evoked 3H overflow with greater sensitivity in slices from AC rats. The β-antagonist propranolol decreased evoked 3H overflow from LV slices of AC rats but not controls. ANG II increased evoked 3H overflow with greater sensitivity in slices from AC rats. These data support the hypothesis that aberrant presynaptic modulation of catecholamine release contributes to sympathetic activation after pressure overload.

scholarly journals Emotion lies in the eye of the listener: emotional arousal to novel sounds is reflected in the sympathetic contribution to the pupil dilation response and the P3

2018 ◽  
Author(s):  
Andreas Widmann ◽  
Erich Schröger ◽  
Nicole Wetzel
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Emotional Arousal ◽  
Oddball Paradigm ◽  
List Type ◽  
Late Component ◽  
Sympathetic Activation ◽  
Novelty P3 ◽  
Related Potentials ◽  
Sympathetic Nervous

AbstractNovel sounds in the auditory oddball paradigm elicit a biphasic dilation of the pupil (PDR) and P3a as well as novelty P3 event-related potentials (ERPs). The biphasic PDR has been hypothesized to reflect the relaxation of the iris sphincter muscle due to parasympathetic inhibition and the constriction of the iris dilator muscle due to sympathetic activation. We measured the PDR and the P3 to neutral and to emotionally arousing negative novels in dark and moderate lighting conditions. By means of principal component analysis (PCA) of the PDR data we extracted two components: the early one was absent in darkness and, thus, presumably reflects parasympathetic inhibition, whereas the late component occurred in darkness and light and presumably reflects sympathetic activation. Importantly, only this sympathetic late component was enhanced for emotionally arousing (as compared to neutral) sounds supporting the hypothesis that emotional arousal specifically activates the sympathetic nervous system. In the ERPs we observed P3a and novelty P3 in response to novel sounds. Both components were enhanced for emotionally arousing (as compared to neutral) novels. Our results demonstrate that sympathetic and parasympathetic contributions to the PDR can be separated and link emotional arousal to sympathetic nervous system activation.HighlightsPDR and ERP effects of novel emotional and neutral oddball sounds were studied.Parasympathetic and sympathetic contributions to the PDR were dissociated by PCA.The parasympathetic PDR component was absent in darkness.Emotional arousal enhanced the sympathetic contribution to the PDR and the P3 ERP.Effects of emotional arousal are mediated by the sympathetic pathway.

scholarly journals Postmenopausal hypertension: role of the sympathetic nervous system in an animal model

2014 ◽  
Vol 306 (4) ◽  
pp. R248-R256 ◽  
Author(s):  
Rodrigo O. Maranon ◽  
Roberta Lima ◽  
Mohammed Mathbout ◽  
Jussara M. do Carmo ◽  
John E. Hall ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Female Rats ◽  
Renal Nerves ◽  
Adrenergic Blockade ◽  
Sympathetic Activation ◽  
Young Females ◽  
Sympathetic Nervous ◽  
Old Females

In postmenopausal women the mechanisms responsible for hypertension have not been completely elucidated, and there are no gender-specific guidelines for women despite studies showing that blood pressure is not as well controlled to goal in women as in men. In the present study we tested the hypotheses that the sympathetic nervous system and the renal sympathetic nerves contribute to hypertension in aging female rats, that sympathetic activation may be mediated by the melanocortin 3/4 receptor (MC3/4R), and that MC3/4R activation may be due to increases in leptin. α-1, β-1,2-Adrenergic blockade reduced blood pressure in both young (3–4 mo) and old (18–19 mo) female spontaneously hypertensive rats (SHR). Renal denervation attenuated the hypertension more in old females than young females. MC3/4R antagonism with SHU-9119 given intracerebroventricularly had no effect on blood pressure in either young or old females but significantly reduced blood pressure in old males. Plasma leptin levels were similar in old male and female SHR and in old versus young females. These data suggest that the hypertension in old female SHR is in part due to activation of the sympathetic nervous system, that the renal nerves contribute to the hypertension, and that the mechanism responsible for sympathetic activation in old females is independent of the MC3/4R.

Thyroid hormone-catecholamine interrelationships during exposure to cold

1981 ◽  
Vol 97 (1) ◽  
pp. 91-97 ◽  
Author(s):  
H. Storm ◽  
C. van Hardeveld ◽  
A. A. H. Kassenaar
Keyword(s):  
Nervous System ◽  
Plasma Concentration ◽  
Thyroid Hormone ◽  
Sympathetic Nervous System ◽  
Plasma Levels ◽  
Surgical Procedure ◽  
Exposure To Cold ◽  
Basal Plasma ◽  
Sympathetic Nervous

Abstract. Basal plasma levels for adrenalin (A), noradrenalin (NA), l-triiodothyronine (T3), and l-thyroxine (T4) were determined in rats with a chronically inserted catheter. The experiments described in this report were started 3 days after the surgical procedure when T3 and T4 levels had returned to normal. Basal levels for the catecholamines were reached already 4 h after the operation. The T3/T4 ratio in plasma was significantly increased after 3, 7, and 14 days in rats kept at 4°C and the same holds for the iodide in the 24-h urine after 7 and 14 days at 4°C. The venous NA plasma concentration was increased 6- to 12-fold during the same period of exposure to cold, whereas the A concentration remained at the basal level. During infusion of NA at 23°C the T3/T4 ratio in plasma was significantly increased after 7 days compared to pair-fed controls, and the same holds for the iodide excretion in the 24-h urine. This paper presents further evidence for a role of the sympathetic nervous system on T4 metabolism in rats at resting conditions.

Sign in / Sign up

Export Citation Format

Share Document