Tone In Healthy Subjects Research Articles

Effect of osteopathic techniques on human resting muscle tone in healthy subjects using myotonometry: a factorial randomized trial

Musculoskeletal disorders (MSDs) are highly prevalent, burdensome, and putatively associated with an altered human resting muscle tone (HRMT). Osteopathic manipulative treatment (OMT) is commonly and effectively applied to treat MSDs and reputedly influences the HRMT. Arguably, OMT may modulate alterations in HRMT underlying MSDs. However, there is sparse evidence even for the effect of OMT on HRMT in healthy subjects. A 3 × 3 factorial randomised trial was performed to investigate the effect of myofascial release (MRT), muscle energy (MET), and soft tissue techniques (STT) on the HRMT of the corrugator supercilii (CS), superficial masseter (SM), and upper trapezius muscles (UT) in healthy subjects in Hamburg, Germany. Participants were randomised into three groups (1:1:1 allocation ratio) receiving treatment, according to different muscle-technique pairings, over the course of three sessions with one-week washout periods. We assessed the effect of osteopathic techniques on muscle tone (F), biomechanical (S, D), and viscoelastic properties (R, C) from baseline to follow-up (primary objective) and tested if specific muscle-technique pairs modulate the effect pre- to post-intervention (secondary objective) using the MyotonPRO (at rest). Ancillary, we investigate if these putative effects may differ between the sexes. Data were analysed using descriptive (mean, standard deviation, and quantiles) and inductive statistics (Bayesian ANOVA). 59 healthy participants were randomised into three groups and two subjects dropped out from one group (n = 20; n = 20; n = 19–2). The CS produced frequent measurement errors and was excluded from analysis. OMT significantly changed F (−0.163 [0.060]; p = 0.008), S (−3.060 [1.563]; p = 0.048), R (0.594 [0.141]; p < 0.001), and C (0.038 [0.017]; p = 0.028) but not D (0.011 [0.017]; p = 0.527). The effect was not significantly modulated by muscle-technique pairings (p > 0.05). Subgroup analysis revealed a significant sex-specific difference for F from baseline to follow-up. No adverse events were reported. OMT modified the HRMT in healthy subjects which may inform future research on MSDs. In detail, MRT, MET, and STT reduced the muscle tone (F), decreased biomechanical (S not D), and increased viscoelastic properties (R and C) of the SM and UT (CS was not measurable). However, the effect on HRMT was not modulated by muscle–technique interaction and showed sex-specific differences only for F.Trial registration German Clinical Trial Register (DRKS00020393).

Ультранизкочастотная динамика подсистем вегетативной регуляции ритма сердца и сосудистого тонуса у здоровых лиц

Ультранизкочастотная динамика подсистем вегетативной регуляции ритма сердца и сосудистого тонуса у здоровых лиц

Effectiveness of deep dry needling on muscle tone in healthy subjects

Effectiveness of deep dry needling on muscle tone in healthy subjects

The effects of Kinesio taping on muscle tone in healthy subjects: A double-blind, placebo-controlled crossover trial

Kinesio taping (KT) has been proposed to modulate muscle tone. However no studies have systematically studied the efficacy of KT on this primary outcome measure. The objective of this study was to determine the effect of Kinesio taping (KT) applied over the gastrocnemius muscles on muscle tone, extensibility, electromyography (EMG) and strength. Nineteen healthy subjects were enrolled in a double-blind, placebo-controlled crossover trial. KT and sham-tape were applied onto the gastrocnemius muscles of all subjects in two randomized sessions. Measurements before, at 10 min and 24 h after the intervention were taken. Outcome measurements included passive resistive torque to ankle dorsiflexion, dorsiflexion passive range of motion (PROM), surface Gastrocnemius Medialis (GM) EMG and maximal isometric voluntary force (MIVF). No significant differences were found between the sham-tape and KT groups for passive resistive torque, PROM nor maximal plantarflexion isometric voluntary force. A short-term increase of GM EMG activity was found in the KT group during the PROM mobilization, which was not maintained at 24 h following treatment. A short-term decrease in dorsiflexion force was produced 10 min after KT with respect to sham-tape application. These results demonstrate that the application of KT in the gastrocnemius muscles has no effect on healthy muscle tone, extensibility nor strength. However a short-term increase of GM EMG activity after KT treatment suggests the activation of central nervous system mechanisms, although without a therapeutic implication. Further studies with more appropriate designs are needed to clarify the physiological and therapeutic effects of this taping technique.

Light and Heavy Touch Reduces Postural Sway and Modifies Axial Tone in Parkinson’s Disease

Background. Light touch with a stable object reduces postural sway by increasing axial postural tone in healthy subjects. However, it is unknown whether subjects with Parkinson’s disease (PD), who have more postural sway and higher axial postural tone than healthy subjects, can benefit from haptic touch. Objective. To investigate the effect of light and heavy touch on postural stability and hip tone in subjects with PD. Methods. Fourteen subjects with mid-stage PD and 14 healthy control subjects were evaluated during quiet standing with eyes closed with their arms (a) crossed, (b) lightly touching a fixed rigid bar in front of them, and (c) firmly gripping the bar. Postural sway was measured with a forceplate, and axial hip tone was quantified using a unique device that measures the resistance of the hips to yaw rotation while maintaining active stance. Results. Subjects with PD significantly decreased their postural sway with light or heavy touch (P < .001 vs arms crossed), similarly as control subjects. Without touch, hip tone was larger in PD subjects. With touch, however, tone values were similar in both groups. This change in hip tone with touch was highly correlated with the initial amount of tone (PD, r = −.72 to −.95; controls, r = −.74 to −.85). Conclusions. The authors showed, for the first time, that subjects with PD benefit from touch similarly to control subjects and that despite higher axial postural tone, PD subjects are able to modulate their tone with touch. Future studies should investigate the complex relationship between touch and postural tone.

057 The role of cytochrome p450 metabolites as an endothelium-derived hyperpolarising factor in the regulation of vascular tone in vivo in the forearm vasculature of healthy and diabetic individuals

Background Epoxyeicosatrienoic acids are arachidonic-acid-derived products of cytochrome P450 (CYP450) epoxygenases. Endothelium-derived hyperpolarizing factor (EDHF) stimulates calcium dependent potassium channels by CYP450 metabolites that can be inhibited with fluconazole (FLU). The role of EDHF in impaired endothelial function remains undefined. We hypothesised a differential contribution of EDHF in diabetics (DM) compared to healthy subjects. Methods In 16 healthy and 14 DM subjects, we measured forearm blood flow (FBF) with venous occlusion strain gauge plethysmography at rest and after endothelium-dependent and -independent vasodilation with acetylcholine (7.5, 15, 30 μg/min) or bradykinin (100, 200, 400 ng/min) and sodium nitroprusside (1.6 and 3.2 μg/min), respectively. Measurements were repeated after NO blockade with LNG monomethyl arginine (L-NMMA, 8 μmol/min), CYP450 blockade with fluconazole (0.4–1.6 μmol/min) and combined NO and CYP450 blockade. Results L-NMMA reduced resting FBF by −1.75 mls/min (p Conclusions NO is the major contributor to resting vasodilator tone in healthy subjects, whereas both NO and hyperpolarisation via CYP450 metabolites contribute to resting tone in DM. However, in the absence of NO in healthy subjects CYP450 metabolites were observed to have an important contribution suggesting an upregulation of EDHF activity via CYP450 metabolites when there is a decreased NO bioavailability. CYP450 metabolites do not contribute to pharmacologically stimulated vasodilation in either DM or healthy subjects, but whether other EDHFs play a role needs to be studied.

Effects of Manual Lymph Drainage on Cardiac Autonomic Tone in Healthy Subjects

This study was designed to investigate the effects of manual lymph drainage on the cardiac autonomic tone. Thirty-two healthy male subjects were randomly assigned to manual lymph drainage (MLD) (experimental) and rest (control) groups. Electrocardiogram (ECG) parameters were recorded with bipolar electrocardiography using standard limb lead positions. The pressure-pain threshold (PPT) was quantitatively measured using an algometer. Heart rate variability differed significantly between the experimental and control groups (p < 0.05), but the PPT in the upper trapezius muscle did not (p > 0.05). These findings indicate that the application of MLD was effective in reducing the activity of the sympathetic nervous system.

Inhibitory effects of stress on postprandial gastric myoelectrical activity and vagal tone in healthy subjects

The aim was to investigate gastric myoelectrical activity (GMA) and vagal activity in response to stress. The study was performed in 10 healthy subjects in three sessions (control, relaxation and stress). The control session was composed of 30-min recordings before and 30-min recordings after a test meal. The protocol of two other sessions was similar except that the fasting recording was extended to 60 min and the subjects were continuously watching a horror movie (stress) or guided meditation tape (relaxation) after the 30-min baseline. GMA was recorded using electrogastrography and heart rate variability (HRV) was derived from the electrocardiogram. Meal resulted in a postprandial increase in the dominant frequency (2.91 cpm vs 3.17 cpm, P < 0.007), dominant power (30.0 dB vs 32.5 dB, P < 0.05), and percentage of normal slow waves (79.8%vs 87.4%, P = 0.09). Similar responses were found in the relaxation session. Stress inhibited all these normal postprandial response and reduced the regularity of gastric slow waves (82.0%vs 66.0%, P < 0.01). In addition, spectral analysis of the HRV demonstrated an inhibition of postprandial vagal activity and an increase of postprandial sympathetic activity with stress. Stress has an inhibitory effect on postprandial GMA and this may involve both vagal and sympathetic pathway.

Modulatory effect of repetitive peripheral magnetic stimulation on skeletal muscle tone in healthy subjects: stabilization of the elbow joint.

To investigate the role of repetitive peripheral magnetic stimulation (RPMS) on the postural component of motor performances, the long-lasting modulatory effect of RPMS on the stabilization of the elbow joint was examined in 13 healthy subjects. The resistance against very slow passive movements in the relaxed state was recorded simultaneously with the electromyogram (EMG) of the forearm extensor and flexor muscles. The experiments show that RPMS performed on the forearm flexor muscles increased the degree of stabilization of the elbow joint, whereas RPMS on the forearm extensor muscles caused a decrease in stabilization. This leads to the assumption that the postural component of motor tasks depends on the motor task itself: motor tasks like manipulation, pointing or grasping which are fine skilled movements require an increase in stabilization while goal-directed movements require a decrease in stabilization. Therefore RPMS is involved in sensorimotor integration and may modulate the motor program at the cortical level.

Stimulation of the nitric oxide–guanosine 3′, 5′-cyclic monophosphate pathway by sildenafil: Effect on rectal muscle tone, distensibility, and perception in health and in irritable bowel syndrome

Objectives Nitric oxide, a neurotransmitter in the noncholinergic, nonadrenergic nervous system, is a mediator of relaxation of GI smooth muscle and of visceral nociception mainly studied in vitro. Sildenafil stimulates the nitric oxide guanosine 3′, 5′-cyclic monophosphate (NO-cGMP) pathway through inhibition of phosphodiesterase 5. The aims of this study were to evaluate in vivo the effect of stimulation of the NO-cGMP pathway on rectal tone, distensibility, and perception in healthy individuals and in patients with irritable bowel syndrome (IBS). Methods In eight healthy subjects and four patients with IBS rectal tone, distensibility and perception thresholds were measured with an electronic barostat both before and 60 min after administration of sildenafil (50 mg p.o.). Perception was scored on a graded scale of 0–6. At the end of a distension series an anatomic questionnaire was filled out by the subjects. Results Sildenafil significantly reduced rectal tone in healthy subjects (intrabag volume predrug: 145.5 ± 18.7 ml vs postdrug: 164.4 ± 16.9 ml, p = 0.01) and IBS (111.3 ± 25.2 ml vs 136.5 ± 33.3 ml; p = 0.01) but did not alter rectal compliance (healthy subjects: 5.8 ± 0.4 vs 6.3 ± 0.6 ml/mm Hg, p > 0.05; IBS subjects: 6.1 ± 0.6 vs 7.1 ± 1.0 ml/mm Hg, p > 0.05). Intrabag pressure and rectal wall tension to reach perception thresholds for initial sensation, sensation of stool, and urgency were not altered by sildenafil. However, intrabag volumes to reach these thresholds were significantly increased by sildenafil both in healthy subjects and in patients with IBS. Viscerosomatic referral was unchanged. Conclusions Stimulation of the NO-cGMP pathway decreases rectal tone but does not influence rectal distensibility. Relaxation of the rectum is accompanied by an increase in rectal volumes to reach perception thresholds in healthy subjects and in patients with IBS, but no direct effect on rectal perception can be demonstrated.

Atrial natriuretic peptide regulates regional vascular volume and venous tone in humans.

To date, the contribution of basal atrial natriuretic peptide (ANP) levels to resting vascular function in humans is unknown. In the present study we sought to investigate the role of ANP in regulating regional vascular volume and venous tone in healthy subjects. We used radionuclide plethysmography to examine the effects of ANP and the ANP-receptor antagonist A71915 on forearm vascular volume. Creating pressure/volume relations, we determined changes in vascular volume, compliance, and tone. Performing dose-ranging studies, we additionally assessed the potency and specificity of A71915 in the forearm resistance vasculature. Equilibrium blood pool scintigraphy was then used to assess the effects of systemic administration of A71915 on regional intestinal vascular volume. Infusion of ANP increased forearm vascular volume in a dose-dependent manner (maximum 20%; P<0.001), exerting a maximum venodilating effect at plasma levels similar to that seen in heart failure. A71915 increased venous tone, thereby decreasing vascular volume by 9.6+/-1.1%, P<0.001 (forearm), and 2.6+/-0.5%, P=0.01 (intestinal beds). At an infusion ratio of 50:1, A71915 almost completely abolished the effects of ANP on forearm blood flow. ANP locally regulates regional vascular volume and tone without affecting compliance.

Effect of the 5‐HT1 agonist sumatriptan on oesophageal motor pattern in patients with ineffective oesophageal motility

The 5-HT1 agonist sumatriptan (SUM) elicits an increase in amplitude of oesophageal motor waves and of lower oesophageal sphincter (LOS) tone in healthy subjects. The aim of the study was to evaluate whether such an effect occurs also in patients with ineffective oesophageal motility (IOM). 16 patients (nine males and seven females, age range 34-55 years) with chest pain and mild to moderate dysphagia were studied; all had undergone previous cardiologic, radiologic and upper gastrointestinal endoscopic exams that were normal. An oesophageal manometry was performed using an electronic probe to record swallows, oesophageal, LOS and gastric motility. The patients whose motor pattern were compatible with IOM (>30% of motor waves with amplitude <30 mmHg and/or non-transmitted) received SUM or placebo 6 mg s.c., injected in the morning and in the afternoon in a random order. The data analysis was limited to 1 h before and 1 h after the drug injections. Ten out of the 16 patients showed an IOM motor pattern. The administration of SUM caused a significant increase in the number of swallows (SUM 99.5 +/- 15.4 vs 78.6 +/- 16.1 basal, P = 0.03) and of primary oesophageal motor waves (SUM 89.6 +/- 13.4 vs 67.2 +/- 12.9 basal, P = 0.04) with no significant changes in the percentage of swallows associated with propagation. Placebo was not associated with increase in the number of swallows (80.3 +/- 14.6, P = 0.9) or of primary oesophageal motor waves (70.1 +/- 12.3, P = 0.7). The amplitude and the percentage of propagated oesophageal motor waves as well as the mean basal LOS tone were unaltered by SUM. There was no change in the symptoms reported after SUM. Although effective in healthy subjects, SUM 6 mg s.c. improves only the numbers but not the amplitude or propagation of oesophageal motility of patients with IOM. The 5-HT1 pathway and its acute stimulation seem to play only a minor role in the pathogenesis of such a disease.

Electrocardiographic criteria for vagotonia—validation with pharmacological parasympathetic blockade in healthy subjects

Background: The importance of vagal tone on cardiac function and cardiovascular mortality is well established. Although the presence of an enhanced cardiac vagal tone (CVT) is frequently diagnosed using the 12-lead resting electrocardiogram (ECG) in daily practice, most of the proposed criteria have been determined on an empirical basis. Our objective was to evaluate the effects of pharmacological blockade of the parasympathetic component of the autonomic nervous system on resting ECG tracings. Methods: Nine healthy young adults (24±5 year-old) underwent parasympathetic blockade with atropine sulfate i.v. (0.04 mg kg −1) and resting ECGs were obtained before and 15 min thereafter. CVT was assessed by a dimensionless index, which measures the RR interval reduction caused by the vagal withdrawal induced by a 4-s exercise test performed on a cycle ergometer where the subjects pedal as fast as possible with no added resistance. Results: This index was 1.63±0.24 and 1.03±0.03, before and after atropine, respectively ( P<0.0001). Atropine reduced the R–R intervals ( P<0.0001), and the amplitude of T-waves in several leads (DII: P=0.03; V4: P=0.04; V5: P=0.03; V6: P=0.01), and abolished the appiculation of T-waves, J-point and ST-segment elevations ( P<0.05), and U-waves ( P<0.05), which were present in baseline ECG in all subjects in at least two leads. The R-wave amplitude in leads V4, V5, and V6 (all P≥0.10) was not modified by atropine infusion. Conclusion: The duration of the R-R intervals and the amplitude of T-waves in leads DII, V4, V5, and V6, and the presence of T-wave appiculation, U-waves, and elevation of J-point and ST-segment should be used to detect enhanced cardiac vagal tone in healthy subjects.

Effects of lipid adminstration in the duodenum and jejunum on visceral sensitivity and gastric tone in healthy subjects

Effects of lipid adminstration in the duodenum and jejunum on visceral sensitivity and gastric tone in healthy subjects

Influence of sumatriptan on gastric fundus tone and on the perception of gastric distension in man

BACKGROUNDIn animals, activation of 5-HT1 like receptors causes a relaxation of the gastric fundus through the activation of intrinsic inhibitory neurones.AIMSTo investigate the effect of sumatriptan, an agonist at enteric...

Continuous wave Doppler ultrasound for evaluation of vasomotor tone of the radial artery

Objective: At present, the sympathetic skin response (SSR) is the only routinely employed technique for evaluating the autonomic function of peripheral nerves. The present study was conducted in order to compare SSR to continuous wave Doppler (CWD) of the radial artery in both healthy control subjects and patients with lower brachial plexus lesions. Methods: Both methods were performed in 50 healthy volunteers (aged 23 to 70 years; mean age and standard deviation, 39.6±14.3 years) and six patients presenting with severe lesions of the lower brachial plexus (aged 22 to 60 years; mean age, 37.6±16.0 years). Results: In each control subject, a SSR could be evoked with a mean latency of 1.2±0.2 s and a mean amplitude of 2.9±1.5 mV. In 45 healthy subjects, CWD revealed both a reduction of systolic, diastolic, and mean peak blood flow velocity after electrical (ES) and acoustic (AS) stimulation as well as after inspiratory cough (IC). The mean latencies to the decrease in flow velocity decrease amounted to 1.8±0.7, 2.0±0.7, and 1.4±0.4 s, respectively. The resistance (Pourcelot) index increased significantly. CWD failed to show changes of blood flow velocity in five healthy subjects due to high sympathetic tone (no baseline diastolic blood flow) or instability of blood flow caused by respiration. In patients with lower brachial plexus lesions, SSR was diminished and changes in blood flow could not be observed on the affected side. Conclusion: CWD sonography allows easy quantitative assessment of arteriolar tone in healthy subjects and patients with autonomic nerve lesions of the limbs.

Contribution of endogenous generation of endothelin-1 to basal vascular tone

Summary Endothelin-1 is an endothelium-derived vasoconstrictor peptide, possibly involved in the pathophysiology of cardiovascular disease. We examined the contribution of endogenously generated endothelin-1 to maintenance of peripheral vascular tone in healthy subjects by local intra-arterial administration of an inhibitor of endothelin converting enzyme, phosphoramidon, and of a selective endothelin receptor A antagonist, BQ-123. Brachial artery infusion of local doses of proendothelin-1, the precursor to endothelin-1, caused a slow-onset dose-dependent forearm vasoconstriction which was abolished by co-infusion of phosphoramidon. Phosphoramidon did not affect responses to endothelin-1. Phosphoramidon caused slow-onset vasodilatation when infused alone, with blood flow increasing by 37% at 90 min (p=0·03). Vasoconstriction to endothelin-1 was abolished by co-infusion of BQ-123 (p=0·006), with forearm blood flow tending to increase. Infusion of BQ-123 alone caused progressive vasodilatation, with blood flow increasing by 64% after 60 min (p=0·007). These results show that endogenous production of endothelin-1 contributes to the maintenance of vascular tone. Endothelin converting enzyme inhibitors and receptor antagonists may have therapeutic potential as vasodilators.

Effect of acute plasma volume expansion on peripheral arteriolar tone in healthy subjects.

1. Using venous occlusion plethysmography, we have investigated the forearm blood flow response in healthy subjects to the acute plasma volume expansion caused by a rapid intravenous infusion of saline. The contribution made to this response by nitric oxide has been investigated using local intra-arterial infusions of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine. 2. The infusion of 1000 ml of saline over 25 min caused plasma volume to increase by about 7%, and resulted in a rise in forearm blood flow, with no change in arterial blood pressure. The onset of the blood flow response occurred within 10 min and blood flow remained elevated above baseline 20 min after the end of the saline infusion. 3. Local intra-arterial infusion of NG-monomethyl-L-arginine alone caused a reduction in forearm blood flow which was maximal at the end of the infusion and gradually recovered to baseline levels over 40 min. 4. When local intra-arterial infusion of NG-monomethyl-L-arginine was followed by plasma volume expansion, the calculated effect of NG-monomethyl-L-arginine was such as to abolish the vasodilator response to saline. 5. The effect of local intra-arterial infusion of NG-monomethyl-L-arginine on forearm blood flow was greater when the drug was given after volume expansion had occurred, than when it was given before the administration of saline. However, in control experiments the vasoconstrictor response to noradrenaline was also enhanced after the administration of the volume load in comparison with the response to noradrenaline given alone.(ABSTRACT TRUNCATED AT 250 WORDS)

AIRWAY VOLUME, AIRWAY RESISTANCE, AND WORK AND FORCE OF BREATHING: THEORY.

Equations for optimal frequencies of breathing at which mechanical work and mean inspiratory force are minimal and which assume dead space and resistance are constant ignore possible changes in airway caliber. We assumed an inverse relationship between resistance and dead space and plotted a series of curves relating mechanical work and mean inspiratory force to frequency of breathing for various dead spaces and corresponding resistances. As dead space increases, the levels of work and inspiratory force fall to minima, then rise; the frequencies at which work and force are minimal increase, then decrease. Adding a series resistance or dead space, changing the resistance/dead space relationship, decreasing lung compliance, or increasing alveolar ventilation do not alter the general shapes of the curves, but change the values of optimal dead space. The optimal dead spaces for minimal work (0.125 liter) and for minimal inspiratory force (0.14 liter) lie within the normal range. Nervously mediated airway tone in healthy subjects may represent optimal adjustment of airway caliber. dead space, optimal; bronchial caliber Submitted on October 26, 1962