Dopamine blockade and natriuresis during water immersion in normal man

1986 ◽  
Vol 70 (5) ◽  
pp. 523-526 ◽  
Author(s):  
P. Coruzzi ◽  
A. Biggi ◽  
L. Musiari ◽  
C. Ravanetti ◽  
P. P. Vescovi ◽  
...  
Keyword(s):  
Creatinine Clearance ◽  
Antidiuretic Hormone ◽  
Water Immersion ◽  
Normal Subjects ◽  
Urine Flow ◽  
Plasma Prolactin ◽  
Normal Man

1. Natriuresis was studied during water immersion in eight normal subjects either in the absence or in the presence of dopamine blockade by domperidone. 2. Creatinine clearance showed no significant changes; urine flow remained significantly above control values during water immersion, implying persistent suppression of antidiuretic hormone. 3. The marked natriuresis seen during water immersion alone was significantly blunted (P < 0.05) but not abolished during water immersion plus domperidone. 4. Suppression of the renin–aldosterone system by water immersion alone was not significantly different from that obtained during water immersion plus dopamine blockade. 5. On the contrary, plasma prolactin levels, previously suppressed during water immersion alone, were significantly stimulated during water immersion plus domperidone, thus indirectly suggesting a role of dopamine in mediating the blunted natriuresis seen during water immersion.

Effects of vasopressin administration on diuresis of water immersion in normal humans

1981 ◽  
Vol 51 (6) ◽  
pp. 1384-1387 ◽  
Author(s):  
M. Epstein ◽  
A. G. DeNunzio ◽  
R. D. Loutzenhiser
Keyword(s):  
Antidiuretic Hormone ◽  
Flow Rate ◽  
Water Immersion ◽  
Normal Subjects ◽  
Urinary Flow Rate ◽  
Urinary Flow ◽  
Relative Role ◽  
Normal Humans

Although previous studies have demonstrated that water immersion to the neck (NI) results in a significant diuresis, the mechanisms are incompletely delineated. Because recent studies in our laboratory have demonstrated that NI is associated with a suppression of antidiuretic hormone (ADH), it is possible that such a suppression mediates the encountered diuresis. The present study was undertaken to assess more directly the relative role of ADH suppression by determining the effects of vasopressin administration. Six hydrated normal subjects were studied on two occasions while undergoing 6 h of NI. During the second NI study, aqueous vasopressin (20 mU/h) was infused for the initial 4 h of study (NI + vasopressin). NI resulted in a significant increase in urinary flow rate beginning during hour 1 and persisting throughout NI. In contrast, during NI + vasopressin, the anticipated diuresis was abolished throughout the 4 h of vasopressin administration. Cessation of vasopressin administration during the final 2 h of NI + vasopressin resulted in a marked and prompt diuresis. The present observations are consistent with the formulation that ADH suppression participates importantly in mediating the diuresis of NI in hydrated normal subjects.

Dissociation of Renin-Aldosterone and Renal Prostaglandin E during Volume Expansion Induced by Immersion in Normal Man

1980 ◽  
Vol 59 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M. Epstein ◽  
M. D. Lifschitz ◽  
R. Re ◽  
E. Haber
Keyword(s):  
Plasma Renin Activity ◽  
Volume Expansion ◽  
Water Immersion ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Prostaglandin E ◽  
Plasma Aldosterone Concentration ◽  
Normal Man

1. The relationship of the renin-angiotensin-aldosterone axis with renal prostaglandin E is complex. Although studies have suggested that these two hormonal systems respond to experimental manipulations in a parallel manner, their interdependence has not been assessed fully during volume expansion. Since studies have demonstrated that in normal man the central hypervolaemia induced by water immersion to the neck produces a prompt and profound suppression of plasma renin activity and plasma aldosterone concentration without concomitant alteration of plasma composition, immersion afforded a unique opportunity to assess simultaneously the effects of central hypervolaemia on plasma renin activity, plasma aldosterone concentration and prostaglandin E excretion. 2. Seven normal subjects were studied twice while in balance on a diet containing 10 mmol of sodium/day, 100 mmol of potassium/day: with indomethacin administration (50 mg given every 6 h for five doses) and without indomethacin. Urinary prostaglandin E excretion was measured hourly and plasma renin activity and plasma aldosterone concentration at 30 min intervals. 3. Immersion was associated with a marked suppression of plasma renin activity (59 ± 7%) and plasma aldosterone concentration (55 ± 3%) with a return to pre-study values during the recovery hour. Concomitantly, urinary prostaglandin E excretion increased from 4.7 to a peak of 10.9 ng/min. Although administration of indomethacin lowered the basal rate of urinary prostaglandin E excretion and plasma renin activity, it did not prevent the subsequent augmentation of urinary prostaglandin E or the suppression of plasma renin activity and plasma aldosterone during the subsequent 4 h of immersion. 4. These results demonstrate a dissociation of renin-aldosterone and prostaglandin E during hypervolaemia and suggest that whereas prostaglandin E may constitute one of the major determinants of renin release clinically and experimentally, these two hormonal systems can be dissociated from each other in response to central volume expansion in man.

Sodium Balance, Urinary Prostaglandin E2 and Renin in Normal Man

1979 ◽  
Vol 57 (s5) ◽  
pp. 267s-269s ◽  
Author(s):  
I. Nielsen ◽  
J. Elmgreen ◽  
P. Christensen ◽  
B. Hesse
Keyword(s):  
Healthy Volunteer ◽  
Essential Role ◽  
Plasma Renin ◽  
Urine Flow ◽  
Sodium Balance ◽  
Sodium Homeostasis ◽  
Salt Restriction ◽  
Normal Man ◽  
Pg E2

1. Urinary prostaglandin (PG) E2 excretion and plasma renin were measured in five healthy volunteer subjects for 2 h after intravenous injection of frusemide (protocol A) and during salt restriction for 7 days with frusemide added on the 2 last days (protocol B). 2. In protocol A, peak values in PGE2 and urine flow were reached in 10–20 min, after which the values rapidly subsided. Plasma renin increased twofold in 60 min. 3. In protocol B, even during severe anti-natriuresis (day 5) and during maximal negative sodium balance (day 7), no change in urinary PGE2 excretion was observed. Plasma renin increased twofold on day 5 and increased tenfold on day 7. 4. The result of protocol B does not suggest any essential role of renal PGE2 for sodium excretion or sodium homeostasis in man. The result of protocol A may point to a role of renal prostaglandins for the diuretic action of frusemide.

Cardiovascular, renal, and endocrine responses in male quadriplegics during head-out water immersion

1990 ◽  
Vol 258 (6) ◽  
pp. R1424-R1430 ◽  
Author(s):  
F. Tajima ◽  
S. Sagawa ◽  
J. Iwamoto ◽  
K. Miki ◽  
B. J. Freund ◽  
...  
Keyword(s):  
Water Immersion ◽  
Urine Volume ◽  
Systolic Pressure ◽  
Free Water ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Urine Flow ◽  
Cervical Cord ◽  
Free Water Clearance ◽  
Normal Men

The present study was undertaken to determine the relative influence of the action of the central nervous system on the mechanism of water-immersion-induced diuresis by comparing physiological responses of quadriplegic (QP) and normal subjects. After overnight fasting seven male QP subjects with complete cervical cord transections (C5-C8) and six normal men were tested before, during, and after 3 h of head-out immersion (HOI) in thermoneutral water (34.5-35.0 degrees C). The reversible increase in urine flow and the total urine volume (309 +/- 53 ml in 3 h) in QP subjects were comparable with that of the normal subjects (318 +/- 96 ml in 3 h). While osmolal excretion was increased in QP subjects, its magnitude was less when compared with that of normal subjects. Instead, the increased urine flow in QP subjects was characterized by increased glomerular filtration rate (GFR) and free water clearance, in contrast to a predominantly osmotic diuresis with no changes in GFR in the normal subjects. The HOI elevated (P less than 0.05) systolic pressure only in QP subjects, whereas the increase in cardiac output was the same in both groups. While plasma renin activity and aldosterone responses to HOI in QP subjects were comparable with those of normal individuals, plasma atrial natriuretic factor (ANF) in QP subjects was twofold higher (P less than 0.05) during HOI, and the approximately threefold increase in ANF (P less than 0.05) in QP subjects due to HOI was the same as that of normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of spontaneous LH release in normo- and hyperprolactinaemic women

1981 ◽  
Vol 97 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Maire T. Buckman ◽  
Glenn T. Peake ◽  
Laxima Srivastava ◽  
Josephine Morris ◽  
Barry David ◽  
...  
Keyword(s):  
Sampling Period ◽  
Normal Subjects ◽  
Plasma Prolactin ◽  
Early Follicular Phase ◽  
Lh Release ◽  
Normal Women ◽  
17 Hydroxyprogesterone ◽  
Group Sex ◽  
Lh Secretion

Abstract. Hyperprolactinaemia may be associated with functional amenorrhoea. In order to evaluate the possible role of abnormal spontaneous LH secretion in hyperprolactinaemic amenorrhoeic women, plasma LH was measured at 15 min intervals for 300 min in 12 normal women during the early follicular phase of the menstrual cycle and compared to that observed in 11 hyperprolactinaemic amenorrhoeic subjects. Mean plasma prolactin was 9.1 ± 3.6 ng/ml (x̄ ± sem) in the euprolactinaemic and 168 ± 32 ng/ml in the hyperprolactinaemic group. Sex steroids including oestrone, oestradiol, progesterone and 17-hydroxyprogesterone were similar in the 2 groups. Mean plasma LH levels over the 300 min sampling period were 9.4 ± 1.6 mIU/ml in the normal subjects and 7.5 ± 1.0 mIU/ml in the hyperprolactinaemic patients (P>0.10). Every normal woman exhibited at least one LH spike in excess of 10 mIU/ml. Five hyperprolactinaemic patients failed to exhibit any LH spikes above 10 mIU/ml (P < 0.02 compared to controls). Thus, hyperprolactinaemia was associated with an absence of LH spike activity in 45% of patients studied and this abnormality may play an aetiologic role in the hypogonadism observed in these subjects; in those hyperprolactinaemic subjects with pulsatile LH secretion, however, other explanations for their amenorrhoea should be considered.

Reflex and mechanical circulatory effects of graded Valsalva maneuvers in normal man

1976 ◽  
Vol 40 (3) ◽  
pp. 434-440 ◽  
Author(s):  
P. I. Korner ◽  
A. M. Tonkin ◽  
J. B. Uther
Keyword(s):  
Valsalva Maneuver ◽  
Peripheral Resistance ◽  
Normal Subjects ◽  
Afferent Input ◽  
Right Atrial ◽  
Response Curves ◽  
Circulatory Response ◽  
Circulatory Effects ◽  
Normal Man

In 17 normal subjects we studied the changes evoked by five levels of expiratory pressure (EP) ranging from 2.5 to 30 mmHg in a number of circulatory variables during the last 10 s of a 30-s Valsalva maneuver. Variables studied included mean arterial (MAP) and pulse (PP) pressures; right atrial (RAP) and peripheral vein (PVP) pressures; cardiac output (CO); total peripheral resistance (TPR) and heart rate (HR). EP-circulatory response curves were obtained in each subject a) before autonomic block; b) after cardiac effector block (atropine + propranolol); c) after “total” autonomic block (atropine + propranolol; guanethidine + phentolamine). Mechanical effects were determined from results during “total” autonomic block. They included EP-related rises in RAP and PVP each to about 0.7 mmHg/mmHg applied EP, and falls in CO, MAP, and PP to levels of approximately 50%, 70%, and 80% of resting respectively at EP 30 mmHg, but no changes in TPR and HR. Reflex effects included EP-related rises in HR and in TPR and in MAP, to levels of 160%, 160%, and 115% of resting respectively at EP 30 mmHg. The afferent input profile is probably complex, and the role of the different receptor groups may vary at the different levels of EP.

Role of the carotid bodies in the heart rate response to breath holding in man

1976 ◽  
Vol 41 (3) ◽  
pp. 336-340 ◽  
Author(s):  
P. M. Gross ◽  
B. J. Whipp ◽  
J. T. Davidson ◽  
S. N. Koyal ◽  
K. Wasserman
Keyword(s):  
Heart Rate ◽  
Heart Rate Response ◽  
Normal Subjects ◽  
The Other ◽  
Breath Holding ◽  
Asthmatic Patients ◽  
Carotid Bodies ◽  
Normal Man

To investigate the role of the carotid bodies in regulating the bradycardia of breath holding in man, we studied heart rate (HR) responses to prolonged breath holding (BH) in five asymptomatic asthmatic patients whose carotid bodies had been resected (CBR). Seven normal subjects served as controls. BH experiments were randomly initiated with single breaths of 100%, 21%,or 12% 92. During BH with 21% O2, normal subjects displayed the typical bradycardia; this response, however, was attenuated with the other O2 concentrations. In contrast, the CBR subjects manifested BH tachycardia which was inversely proportional to the O2 tension. HR increased in be CBR group by 5%, 31%, and 45% during BH with 100%, 21%, and 12% O2, respectively. These results demonstrate that the bradycardia of BH in normal man is under the influence of the carotid bodies. During BH and in the absence of carotid bodies, an O2 tension-dependent tachycardia is unveiled.

The Role of Posture in the Natriuresis of Water Immersion in Normal Man

1973 ◽  
Vol 142 (1) ◽  
pp. 124-127 ◽  
Author(s):  
M. Epstein ◽  
D. C. Duncan ◽  
B. E. Meek
Keyword(s):  
Water Immersion ◽  
Normal Man

Circulating opioid peptides during water immersion in normal man

1988 ◽  
Vol 74 (2) ◽  
pp. 133-136 ◽  
Author(s):  
P. Coruzzi ◽  
C. Ravanetti ◽  
L. Musiari ◽  
A. Biggi ◽  
P. P. Vescovi ◽  
...  
Keyword(s):  
Volume Expansion ◽  
Adrenocorticotropic Hormone ◽  
Control Mechanism ◽  
Water Immersion ◽  
Extracellular Fluid ◽  
Normal Subjects ◽  
Serum Prolactin ◽  
Methionine Enkephalin ◽  
Normal Man ◽  
Circulating Levels

1. This study was designed to evaluate variations in plasma β-endorphin, methionine-enkephalin, adrenocorticotropic hormone and serum prolactin in healthy volunteers during head-out water immersion. 2. Water immersion induced an increase in methionine-enkephalin plasma levels, which was associated with a significant fall in mean arterial pressure and heart rate. 3. Conversely, a suppression of plasma β-endorphin, adrenocorticotropic hormone and serum prolactin was detected during water immersion. 4. We suggest that a dopaminergic inhibitory control mechanism may be involved in regulating circulating levels of β-endorphin, adrenocorticotropic hormone and prolactin in normal subjects undergoing extracellular fluid volume expansion produced by water immersion.

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