Blood Levels Of Noradrenaline Research Articles

Effects of whole-body neuromuscular electrical stimulation device on hemodynamics, arrhythmia, and sublingual microcirculation

Neuromuscular electrical stimulation has been used to treat cardiovascular diseases and other types of muscular dysfunction. A novel whole-body neuromuscular electrical stimulation (WB-NMES) wearable device may be beneficial when combined with voluntary exercises. This study aimed to investigate the safety and effects of the WB-NMES on hemodynamics, arrhythmia, and sublingual microcirculation. The study included 19 healthy Japanese volunteers, aged 22–33 years, who were not using any medication. Electrocardiogram (ECG), echocardiography, and blood sampling were conducted before a 20-min WB-NMES session and at 0 and 10 min after termination of WB-NMES. Their tolerable maximum intensity was recorded using numeric rating scale. Arrhythmia was not detected during neuromuscular electrical stimulation or during 10 min of recovery. Blood pressure, heart rate, left ventricular ejection fraction, and diastolic function remained unchanged; however, mild mitral regurgitation was transiently observed during WB-NMES in a single male participant. A decrease in blood glucose and an increase in blood lactate levels were observed, but no changes in blood fluidity, sublingual microcirculation, blood levels of noradrenaline, or oxidative stress were shown. WB-NMES is safe and effective for decreasing blood glucose and increasing blood lactate levels without changing the blood fluidity or microcirculation in healthy people.

Reduction of heart lesions after experimental restraint stress: a study in stress-susceptible pigs.

Pigs, crossbreeds of Swedish Landrace and Yorkshire, about 6 months old and susceptible to develop malignant hyperthermia when exposed to halothane, were subjected to a 12-min experimental stress provoked by the myorelaxant succinylcholine. The experimental pigs were pre-treated before the stress: five were given propranolol for one week, six were given alpha-tocopherol (vitamin E) combined with selenium for 11 days, and five pigs were pre-treated with zinc (ZnSO4) for 1 month. A total of 12 untreated, stress-susceptible pigs served as controls. The blood levels of noradrenaline and adrenaline recorded during the stress were significantly reduced in the groups pre-treated with propranolol or alpha-tocopherol combined with selenium. The results show significant reduction of myocardial necrosis by beta-adrenoceptor-blocking agents and free-radical scavengers during stress-induced increased sympathetic activity.

The role of sympathetic activity in initiating malignant hyperthermia

The role of sympathetic activity in triggering malignant hyperthermia (MH) is controversial. Increased sympathetic activity has been considered by some to be the causal factor, whilst other believe this activity to be secondary to metabolic events in the MH syndrome. In this study, a number of parameters, including the blood levels of noradrenaline and adrenaline, were followed in pigs susceptible to MH during exposure to halothane. Seven pigs, crossbreeds of Swedish Landrace and Yorkshire, females and castrated males, aged about 9 months were used. Results are presented for individual pigs. One of the pigs was a non-responder. The time of onset for different signs of MH varied greatly, as judged by ten independent observers. Onset of changes in heart rate, muscle temperature, blood PCO2 and pH, plasma adrenaline and noradrenaline could be scored. The metabolic events (increased PCO2 and decreased pH in blood) significantly preceded the signs of increased sympathetic activity (increased heart rate and elevated levels of catecholamines in blood). Our results support the view that increased sympathetic activity does not initiate MH. The sympathetic activity, however, strongly contributes to the fulminant MH syndrome.

On the patterns of blood pressure, heart rate, and blood levels of noradrenaline and adrenaline during haemorrhage in the rat.

Mean arterial blood pressure (MAP), heart rate (HR), and blood levels of noradrenaline (NA) and adrenaline (A) were studied in Sprague-Dawley rats during haemorrhage. The bleeding was performed in different ways towards complete exsanguination or into a reservoir kept at a constant pressure of 35 mmHg. Awake, unstressed rats or rats anaesthetized with different anaesthetics were examined. Four different phases in the reaction patterns were observed during bleeding. The first phase with the parameters studied expected to be at steady state, was found to be very shortlasting. Only very small blood volumes could be drawn without giving signs of interference with sympathetic activity. The second phase with signs of increased sympathetic activity, as increased HR, also was very shortlasting. Thereafter the marked third phase followed with signs of evident sympathetic inhibition, involving marked decreases in MAP, HR, and blood levels of NA. The last period, phase four, showed signs of a second period of increased sympathetic activity with increased HR and blood levels of NA (and A). On bleeding into a reservoir for 4 h signs of all four phases could be observed.

Changes in blood catecholamines, insulin, corticosterone and glucose during the course of the Sephadex inflammation

During an acute inflammation, the blood levels of noradrenaline, dopamine and insulin increase uniformly until the fourth day, then reach a climax which for dopamine is above the norm, while the suppressed levels of noradrenaline and insulin approach the norm. All values decrease on the fifth day (end of the experiment). Glucose behaves inversely, showing a minimum on the fourth day. Corticosterone displays two peaks, on the first and fourth days. The adrenaline level differs distinctly from these patterns: it is elevated on the second, fourth and fifth days. By releasing each catecholamine independently, the organism can possibly influence the course of the inflammation.

Effect of Propranolol on Myocardial Cell Necroses and Blood Levels of Catecholamines in Pigs Subjected to Stress

The degree of myocardial cell necroses in pigs exposed to stress induced by a myorelaxant (succinylcholine) for about 12 min. was investigated. The Beta-adrenoceptor block propranolol was given in varying doses prior to the induced stress. The degree of necroses in these pigs was evaluated according to a point scale, ranging from 0 to 6 points, and compared with the changes found in untreated controls following stress. The blood levels of noradrenaline and adrenaline were assayed before, during an immediately after the period of stress. No protective effect of propranolol on the cardiac lesions was found when the drug was administered intravenously in a single dose of either 1 mg or 3 mg per kg. During the period of stress the blood levels of noradrenaline were high, indicating a high degree of activity in the sympatho-adrenal system. Propranolol in a single dose of 10 mg per kg intravenously reduced the number and size of heart lesions, while the blood levels of the catecholamines were lower under stress than after administration of 1 and 3 mg propranolol. After oral treatment with propranolol, 120 mg three times a day for 6 or 7 days, an almost complete absence of heart cell necrosis after the stress was obtained. The activity of the sympatho-adrenal system was elevated, as reflected by the high blood levels of catecholamines. The results indicate that stress-induced heart cell necrosis is mediated via the activity of the sympatho-adrenal system. The difference between a single and repeated doses of propranolol in protecting the heart suggests a complex of the adrenergic Beta-receptor blocker.