pituitrin and Dizziness

The application of an orthostatic stress such as lower body negative pressure (LBNP) has been proposed to minimize the effects of weightlessness on the cardiovascular system and subsequently to reduce the cardiovascular deconditioning. The KAATSU training is a novel method to induce muscle strength and hypertrophy with blood pooling in capacitance vessels by restricting venous return. Here, we studied the hemodynamic, autonomic nervous and hormonal responses to the restriction of femoral blood flow by KAATSU in healthy male subjects, using the ultrasonography and impedance cardiography. The pressurization on both thighs induced pooling of blood into the legs with pressure-dependent reduction of femoral arterial blood flow. The application of 200 mmHg KAATSU significantly decreased left ventricular diastolic dimension (LVDd), cardiac output (CO) and diameter of inferior vena cava (IVC). Similarly, 200 mmHg KAATSU also decreased stroke volume (SV), which was almost equal to the value in standing. Heart rate (HR) and total peripheral resistance (TPR) increased in a similar manner to standing with slight change of mean blood pressure (mBP). High-frequency power (HF(RR)) decreased during both 200 mmHg KAATSU and standing, while low-frequency/high-frequency power (LF(RR)/HF(RR)) increased significantly. During KAATSU and standing, the concentration of noradrenaline (NA) and vasopressin (ADH) and plasma renin activity (PRA) increased. These results indicate that KAATSU in supine subjects reproduces the effects of standing on HR, SV, TPR, etc., thus stimulating an orthostatic stimulus. And, KAATSU training appears to be a useful method for potential countermeasure like LBNP against orthostatic intolerance after spaceflight.

Topics: Adult; Autonomic Nervous System; Cardiac Output; Dizziness; Exercise; Femoral Artery; Humans; Hypertrophy; Lower Body Negative Pressure; Male; Muscle Strength; Muscles; Norepinephrine; Physical Exertion; Posture; Regional Blood Flow; Renin; Vasopressins; Weightlessness Countermeasures

The aim of the present study was to evaluate the association of neuro-otological examination, blood tests, and scoring questionnaire data with treatment-resistant intractability of persistent dizziness in Ménière's disease.. We managed 1520 successive vertigo/dizziness patients at the Vertigo/Dizziness Center in Nara Medical University from May 2014 to April 2018. Five hundred and twenty-two patients were diagnosed with Ménière's disease (522/1520; 34.3%) according to the 2015 diagnostic guideline of the International Classification of Vestibular Disorders. Among the patients with Ménière's disease there were 102 with intractable rotatory vertigo attacks for more than 3-6 months (102/522; 19.5%), including 20 bilateral cases (20/102; 19.6%), and 88 with intractable unremitting floating sensation rather than rotatory vertigo attacks for more than 3-6 months (88/522; 16.9%), including 28 bilateral cases (28/88; 31.8%). Sixty out of 88 cases with intractable unremitting floating sensation were unilateral and were enrolled for hospitalization to undergo neuro-otological examinations including pure-tone audiometry (PTA), the caloric test (C-test), vestibular evoked cervical myogenic potentials (cVEMP), subjective visual vertical (SVV) test, glycerol test (G-test), electrocochleogram (ECoG), inner ear magnetic resonance imaging (ieMRI), blood tests including anti-diuretic hormone (ADH) and bone alkaline phosphatase (BAP), and self-rating questionnaires of depression score (SDS). Data are presented as positive (+) ratios of the number of patients with examination and questionnaire data outside of the normal range.. The ratios (+) were as follows: C-test=33.3% (20/60), cVEMP=25.0% (15/60), SVV=50.0% (30/60), G-test=55.0% (33/60), ECoG=63.3% (38/60), ieMRI=86.7% (52/60), ADH=35.0% (21/60), BAP=11.7% (7/60), and SDS=40.0% (24/60). Multivariate regression analysis revealed that the periods of persistent dizziness were significantly longer in unilateral Ménière's patients with C-test(+), SVV(+), and SDS(+) compared with those with negative findings. Additionally, the periods in bilateral cases were significantly longer than those in unilateral ones.. Although approximately 70% of patients with Ménière's disease are usually treatable through the appropriate conservative medical therapy, the presence of canal paresis, gravity-sensitive dysfunction, neurosis/depression, and bilaterality may make the persistent dizziness intractable and may thus require additional treatments.

Topics: Adult; Alkaline Phosphatase; Audiometry, Evoked Response; Audiometry, Pure-Tone; Caloric Tests; Depressive Disorder; Dizziness; Ear, Inner; Female; Gravitation; Humans; Magnetic Resonance Imaging; Male; Meniere Disease; Mental Disorders; Middle Aged; Multivariate Analysis; Regression Analysis; Semicircular Canals; Vasopressins; Vestibular Evoked Myogenic Potentials

Cardiovascular deconditioning after a 4-h head-down bed rest (HDBR) might be a consequence of the time of day relative to pre-HDBR testing, or simply 4 h of confinement and inactivity rather than the posture change. Ten men and 11 women were studied during lower body negative pressure (LBNP) before and after 4-h HDBR and 4-h seated posture (SEAT) as a control for time of day and physical inactivity effects to test the hypotheses that cardiovascular deconditioning was a consequence of the HDBR posture, and that women would have a greater deconditioning response. Following HDBR, men and women had lower blood volume, higher heart rate with a greater increase during LBNP, a greater decrease of stroke volume during LBNP, lower central venous pressure, smaller inferior vena cava diameter, higher portal vein resistance index with a greater increase during LBNP, but lower forearm vascular resistance, lower norepinephrine, and lower renin. Women had lower vasopressin and men had higher vasopressin after HDBR, and women had lower pelvic impedance and men higher pelvic impedance. Following SEAT, brachial vascular resistance was reduced, thoracic impedance was elevated, the reduction of central venous pressure during LBNP was changed, women had higher angiotensin II whereas men had lower levels, and pelvic impedance increased in women and decreased in men. Cardiovascular deconditioning was greater after 4-h HDBR than after SEAT. Women and men had similar responses for most cardiovascular variables in the present study that tested the responses to LBNP after short-duration HDBR compared with a control condition.

Topics: Adult; Analysis of Variance; Angiotensin II; Bed Rest; Blood Volume; Brachial Artery; Cardiovascular Deconditioning; Cardiovascular System; Central Venous Pressure; Dizziness; Female; Forearm; Head-Down Tilt; Heart Rate; Hemodynamics; Humans; Lower Body Negative Pressure; Male; Norepinephrine; Pelvis; Portal Vein; Regional Blood Flow; Renin; Sex Factors; Stroke Volume; Time Factors; Vascular Resistance; Vasopressins; Vena Cava, Inferior

An elevation of the plasma antidiuretic hormone (ADH) levels has frequently been observed in Meniere's disease patients. However, little is known regarding the mechanism behind such an elevation of ADH level in Meniere's disease patients. Therefore, we measured the plasma ADH in Meniere's disease patients and other vertigo patients to elucidate the association between the ADH levels, stress levels and the development of Meniere's symptom.. The plasma ADH levels and plasma osmotic pressure were determined in 23 definite Meniere's disease patients and 160 patients with other types of vertigo/dizziness. All participants were administered questionnaire regarding their psychological status including their stress levels.. The ADH levels of Meniere's disease patients in the acute phase (5.80 +/- 1.37 pg/mL) were significantly higher in comparison with that of Meniere's disease patients in the remission phase (2.26 +/- 0.41 pg/mL) (P < 0.05). In other peripheral vertigo patients, the ADH level in the acute phase (1.71 +/- 0.23 pg/mL) was not significantly different from that in the remission phase (1.45 +/- 0.15 pg/mL). Meniere's disease patients in the acute phase had a significantly higher stress score (114 +/- 23) than Meniere's disease patients in the remission phase (56 +/- 13) (P < 0.05). However, there was no significant correlation between their stress score and the ADH levels.. These results suggest that the elevation of the plasma ADH levels in Meniere's disease patients in the acute phase is, therefore, associated with the pathogenesis of Meniere's disease attacks rather than with stress.

Topics: Acute Disease; Adult; Aged, 80 and over; Depression; Dizziness; Female; Humans; Life Change Events; Male; Meniere Disease; Middle Aged; Osmotic Pressure; Remission, Spontaneous; Sex Factors; Stress, Psychological; Vasopressins; Vertigo

To get a more complete picture of cardiovascular regulation after postural changes, this investigation directly monitored volume-related, hemodynamic, and endocrine variables during and after 30 min of passive head-up tilt (HUT) of various degrees. It was hypothesized that the return of variables to pre-tilt control level is of system-specific duration and different from what is found after lower body negative pressure (LBNP).. We tested 7 persons on 5 different days using, in random order, no (HUT0) or different intensity (12 degrees , 30 degrees , 53 degrees , and 70 degrees ) of passive orthostasis (HUT12, HUT30, HUT53, HUT70). Data were collected before (supine), during, and after (supine) HUT and compared with synchronous data from HUT0.. There was graded alteration with the sine of tilt angle for all hormones and directly volume-related variables. The effects of HUT70 were of the same magnitude as previously documented by others. After HUT, hemodynamic variables and catecholamines returned to control levels most rapidly. Heart rate depression, as observed in a companion LBNP study in the same subjects, did not occur. Vasopressin, PRA, plasma volume and Z0 returned to nominal values more slowly. Plasma aldosterone was still elevated 50 min after reassuming supine posture.. Besides specific dose-responses within hemodynamic, volume-dependent, and hormonal variables after orthostatic loading of different degree, the return to control levels after HUT occurs with distinctly different time-courses, which are not identical with those seen after LBNP-simulated orthostasis.

Topics: Adult; Aldosterone; Dizziness; Epinephrine; Gravitation; Hemodynamics; Humans; Hydrocortisone; Lower Body Negative Pressure; Male; Renin-Angiotensin System; Syncope; Tilt-Table Test; Vasopressins

The purpose of this investigation was to test the hypothesis that peripheral vasoconstriction and orthostatic tolerance are associated with increased circulating plasma concentrations of noradrenaline, vasopressin and renin-angiotensin. Sixteen men were categorized as having high (HT, n=9) or low (LT, n=7) tolerance to lower body negative pressure (LBNP) based on whether the endpoint of their pre-syncopal-limited LBNP (peak LBNP) exposure exceeded -60 mmHg. The two groups were matched for age, height, weight, leg volume, blood volume and maximal oxygen uptake, as well as baseline blood volume and plasma concentrations of vasoactive hormones. Peak LBNP induced similar reductions in mean arterial pressure in both groups. The reduction in leg arterial pulse volume (measured by impedance rheography), an index of peripheral vascular constriction, from baseline to peak LBNP was greater (P<0.05) in the HT group (-0.041 +/- 0.005 ml 100 ml-1) compared to the reduction in the LT group (-0. 025 +/- 0.003 ml 100 ml-1). Greater peak LBNP in the HT group was associated with higher (P<0.05) average elevations in plasma concentrations of vasopressin (pVP, Delta=+7.2 +/- 2.0 pg ml-1) and plasma renin-angiotensin (PRA, Delta=+2.9 +/- 1.3 ng Ang II ml-1 h-1) compared to average elevations of pVP (+2.2 +/- 1.0 pg ml-1) and PRA (+0.1 +/- 0.1 ng Ang II ml-1 h-1) in the LT group. Plasma noradrenaline concentrations were increased (P<0.05) from baseline to peak LBNP in both HT and LT groups, with no statistically distinguishable difference between groups. These data suggest that the renin-angiotensin and vasopressin systems may contribute to sustaining arterial pressure and orthostatic tolerance by their vasoconstrictive actions.

Topics: Adult; Blood Pressure; Dizziness; Humans; Lower Body Negative Pressure; Male; Norepinephrine; Renin-Angiotensin System; Vascular Resistance; Vasoconstriction; Vasopressins

The standard human vection model utilized for nausea has been an optokinetic drum. This model may be difficult to extrapolate to the usual clinical setting. Our goals were to develop an experimental model which could induce low grade nausea in humans and to determine the relationship between mild nausea and changes in the electrogastrogram and plasma vasopressin concentrations.. Twenty-one volunteers (11 males, mean age: 37 years) participated. At baseline and throughout the study the electrogastrogram was monitored, blood was drawn for vasopressin assay and symptoms of nausea, dizziness and headache were rated on a 0-10-point scale. Subjects were semireclined in a darkened room while viewing moving bars of light rotating at a rate of 85 degrees s-1. Subjects were asked to rate their proneness to motion sickness and their current level of anxiety at baseline.. Eight subjects developed mild to moderate (mean: 3.6) nausea during vection. Symptoms of nausea were correlated with a reported history of motion sickness (r = 0.49, P < 0.05) but not with anxiety (r = 0.14, P = 0.54). Degrees of nausea correlated with degrees of dizziness (r = 0.47, P < 0.05) but not with headache (r = 0.29, P = 0.14). Subjects who developed mild nausea were not significantly more likely to exhibit altered electrogastrogram or vasopressin than subjects who did not report nausea. Vasopressin levels during baseline and experimental conditions were highly correlated (r = 0.66, P < 0.005 and r = 0.55 P < 0.005, respectively) with reported baseline anxiety.. (1) This new model in humans induced mild nausea that was unrelated to electrogastrogram and vasopressin abnormalities, (2) high correlation between anxiety and vasopressin suggests that vasopressin may not be directly related to nausea, and (3) these data indicate that onset of nausea mediated centrally can occur without associated electrogastrogram changes.

Topics: Adult; Aged; Anxiety; Dizziness; Electromyography; Female; Headache; Humans; Illusions; Male; Middle Aged; Models, Biological; Motion Sickness; Muscle, Smooth; Myoelectric Complex, Migrating; Nausea; Nystagmus, Optokinetic; Reference Values; Regression Analysis; Stomach; Vasopressins

Plasma antidiuretic hormone (p-ADH) concentrations were determined with a radioimmunoassay, using a reversed-phase C18 silica column, in 300 patients with vertigo, dizziness and/or deafness; 119 of them had a diagnosis of Menière's disease. The p-ADH level was significantly elevated in patients with Meniere's disease and others with endolymphatic hydrops, e.g. cochlear Menière's disease or delayed hydrops. By contrast, the p-ADH level was not so high in cases without the endolymphatic hydrops. The increase in the p-ADH level was closely linked to vertigo attacks, the glycerol test results and an enhanced negative summating potential (-SP) in electrocochleogram (ECochG). These results lead to the assumption that disorders of ADH-dependent hormonal control in the inner ear may constitute the possible mechanism underlying vertiginous attacks and deafness in patients with endolymphatic hydrops.

Topics: Cochlea; Deafness; Dizziness; Edema; Electrophysiology; Endolymphatic Hydrops; Glycerol; Heating; Humans; Meniere Disease; Vasopressins; Vertigo