Interaction of captopril and ibuprofen on glomerular and tubular function in humans

1990 ◽  
Vol 259 (2) ◽  
pp. F233-F238
Author(s):  
M. Allon ◽  
C. B. Pasque ◽  
M. Rodriguez
Keyword(s):  
Renal Plasma Flow ◽  
Urine Volume ◽  
Normal Subjects ◽  
Acute Administration ◽  
Distal Nephron ◽  
Water Diuresis ◽  
Water Handling ◽  
Patients With Heart Failure ◽  
Before And After ◽  
Opposing Effects

Renal hemodynamics and tubular solute and water handling were evaluated in normal subjects during water diuresis, before and after the acute administration of captopril, ibuprofen, or the combination of both drugs. The glomerular filtration increased after captopril administration but did not change after ibuprofen alone or in combination with captopril. Renal plasma flow increased with captopril alone and captopril plus ibuprofen but did not change after ibuprofen alone. Urine volume and Na excretion increased with captopril and decreased after ibuprofen; coadministration of ibuprofen attenuated the tubular effects produced by captopril alone. FELi, fractional delivery of solute to the distal nephron, and FELi-FENa, fractional distal reabsorption of solute, both significantly increased after captopril and decreased after ibuprofen but did not change with the combined regimen. (FELi-FENa)/FELi, fractional reabsorption of distally delivered Na, significantly decreased after captopril and increased after ibuprofen but remained unchanged after captopril plus ibuprofen. Thus captopril and ibuprofen have opposing effects on tubular Na and water handling, which are attenuated by the addition of the other drug. This interaction may have clinical relevance in patients with heart failure or hypertension, in whom captopril is used to enhance Na and water diuresis.

Pressor responses to norepinephrine in humans before and after corticosteroids

1962 ◽  
Vol 203 (5) ◽  
pp. 961-963 ◽  
Author(s):  
Mohinder P. Sambhi ◽  
Max H. Weil ◽  
Vasant N. Udhoji
Keyword(s):  
Human Subject ◽  
Normal Subjects ◽  
Adrenal Function ◽  
Variance Analysis ◽  
Acute Administration ◽  
Intravenous Injections ◽  
Pressor Responses ◽  
Before And After

Pressor responses produced by intravenous injections of graded doses of norepinephrine were recorded in ten normal subjects before and after pharmacologic doses of glucocorticoids. Two subjects had been pretreated with 9α-fluorocortisol. Although a considerable variation was found in the responsiveness to repeated norepinephrine injections, variance analysis demonstrated that administration of adrenal cortical hormones and their analogues did not significantly alter the response. These observations do not support the hypothesis that acute administration of corticosteroids in large doses potentiates the pressor effects of catecholamines in the human subject with normal adrenal function.

Effect of acute unilateral renal denervation on tubular sodium reabsorption in the dog

1977 ◽  
Vol 232 (1) ◽  
pp. F16-F19
Author(s):  
G. Nomura ◽  
T. Takabatake ◽  
S. Arai ◽  
D. Uno ◽  
M. Shimao ◽  
...  
Keyword(s):  
Renal Denervation ◽  
Renal Plasma Flow ◽  
Free Water ◽  
Sodium Reabsorption ◽  
Distal Nephron ◽  
Water Diuresis ◽  
Free Water Clearance ◽  
Water Excretion ◽  
Tubular Sodium Reabsorption ◽  
Renal Tubular

The effects of acute denervation of the kidney on renal tubular sodium and water excretion were studied in anesthetized, hypophysectomized, and cortisone-treated mongrel dogs during stable water diuresis produced by the infusion of 2.5% dextrose. In all experiments, denervation natriuresis, and diuresis were observed without significant change in glomerular filtration rate (GRF) and renal plasma flow (RPF). Fractional sodium delivery to the distal nephron (CNa + CH2O/100 ml GFR) and fractional free water clearance (CH23/100 ml GFR) was significantly greater in the denervated kidney compared with the innervated kidney (9.6+/-1.2 vs. 6.7+/-0.9% and 8.8+/-1.2 vs. 6.5+/-0.8%, respectively). Distal tubular sodium reabsorption (CH2O/(CNa + CH2O)) was not significantly different. We conclude that renal denervation primarily affects the proximal tubule as manifested by a decrease in the reabsorption of sodium and water. A small effect of denervation on the distal nephron is not completely ruled out.

Aminophylline and human diaphragm strength in vivo

1990 ◽  
Vol 68 (6) ◽  
pp. 2591-2596 ◽  
Author(s):  
R. D. Levy ◽  
S. Nava ◽  
L. Gibbons ◽  
F. Bellemare
Keyword(s):  
Motor Units ◽  
Normal Subjects ◽  
Acute Administration ◽  
Transdiaphragmatic Pressure ◽  
Gastric Pressure ◽  
Significant Difference ◽  
Before And After ◽  
Normal Human ◽  
Twitch Characteristics

The transdiaphragmatic pressure (Pdi) twitch response to single shocks from supramaximal bilateral phrenic nerve stimulation was studied before and after acute intravenous infusions of aminophylline [14.9 +/- 3.1 (SD) micrograms/ml] in nine normal subjects. Stimulation was performed with subjects in the sitting position against an occluded airway from end expiration. Baseline gastric pressure and abdominal and rib cage configuration were kept constant. There was no significant difference in peak twitch Pdi from the relaxed diaphragm between control (38.8 +/- 3.3 cmH2O) and aminophylline (40.2 +/- 5.2 cmH2O) experiments. Other twitch characteristics including contraction time, half-relaxation time, and maximum relaxation rate were also unchanged. The Pdi-twitch amplitude at different levels of voluntary Pdi was measured with the twitch occlusion technique, and this relationship was found to be similar under control conditions and after aminophylline. With this technique, maximum Pdi (Pdimax) was calculated as the Pdi at which stimulation would result in no Pdi twitch because all motor units are already maximally activated. No significant change was found in mean calculated Pdimax between control (146.9 +/- 27.0 cmH2O) and aminophylline (149.2 +/- 26.0 cmH2O) experiments. We conclude from this study that the acute administration of aminophylline at therapeutic concentrations does not significantly affect contractility or maximum strength of the normal human diaphragm in vivo.

On the role of dopamine receptors in the central regulation of human TSH

1981 ◽  
Vol 98 (4) ◽  
pp. 521-527 ◽  
Author(s):  
G. Delitala ◽  
L. Devilla ◽  
A. Canessa ◽  
F. D'Asta
Keyword(s):  
Dopamine Receptors ◽  
Blood Brain Barrier ◽  
Median Eminence ◽  
Normal Subjects ◽  
Acute Administration ◽  
Central Regulation ◽  
Before And After ◽  
Tsh Secretion ◽  
Substituted Benzamides

Abstract. The effects of acute administration of haloperidol (4 mg im) and pimozide (4 mg orally) on TSH and Prl secretion were studied in normal and hypothyroid man. The TRH-induced TSH secretion before and after pre-medication with pimozide and domperidone, a peripheral dopamine (DA) blocker, was also evaluated in a group of normal subjects. Haloperidol and pimozide induced a marked increment in serum Prl; mean Prl levels were still significantly elevated 12 h following pimozide administration. A small but significant TSH increase was observed following haloperidol and pimozide in normal as well as hypothyroid subjects. Both domperidone and pimozide significantly enhanced TRH-induced TSH release. In another experiment 3 women with primary thyroid failure received an infusion of DA (4 (μg/kg/min for 4 h) with and without domperidone administration. TSH and Prl levels were suppressed by DA, but the effect was completely abolished by domperidone. The results suggest that psychotrophic drugs, such as haloperidol and pimozide, can, like substituted benzamides, stimulate TSH release in man. Since domperidone and DA do not cross the blood-brain-barrier and domperidone significantly enhanced the TSH response to TRH, the data also support the hypothesis that human TSH is regulated by DA at the hypothalamus (median eminence) and/or pituitary level.

Plasma and tissue kallikrein–kinin systems during acute administration of frusemide in normotensive and hypertensive humans

1991 ◽  
Vol 81 (3) ◽  
pp. 305-311 ◽  
Author(s):  
K. Peter Öhman ◽  
Bengt E. Karlberg
Keyword(s):  
Plasma Level ◽  
Urine Volume ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Primary Hypertension ◽  
Plasma Kallikrein ◽  
Acute Administration ◽  
Tissue Kallikrein ◽  
Kinin System ◽  
Hypertensive Patients

1. This study aims to further elucidate the role of the tissue and plasma kallikrein-kinin systems in blood pressure, electrolyte and volume homoeostasis. Components thereof and of the renin-angiotensin-aldosterone system were measured in conjunction with frusemide administration, in normotensive subjects and in patients with primary hypertension. 2. Frusemide increased plasma pre-kallikrein, angiotensin II and aldosterone concentrations and plasma renin activity, whereas the plasma level of tissue kallikrein remained unchanged. Basal values and the induced changes were similar in both groups. 3. Frusemide increased the urine volume and the excretion of Na+, K+, Mg2+, Cl−, aldosterone, prostaglandin E2 and tissue kallikrein. These changes were similar in both groups, but the total tissue kallikrein excretion was significantly lower in the hypertensive patients. Excretion of electrolytes and hormones was also measured during three 24 h urine collection periods and did not differ between the two groups. 4. Thus, acute administration of frusemide to hypertensive patients and normal subjects increased the plasma level of pre-kallikrein, possibly indicating less activation to kallikrein and subsequently less kinin generation in the blood stream. This also suggests a role for the plasma kallikrein-kinin system in the regulation of vascular tone and blood volume. Circulating tissue kallikrein does not seem to be acutely involved. 5. Urinary excretion of kallikrein is reduced in patients with primary hypertension after the administration of frusemide, apparently without affecting the renal excretory response.

Acute unilateral renal denervation in rats with extracellular volume expansion

1977 ◽  
Vol 232 (1) ◽  
pp. F26-F32 ◽  
Author(s):  
E. Bello-Reuss ◽  
E. Pastoriza-Munoz ◽  
R. E. Colindres
Keyword(s):  
Volume Expansion ◽  
Renal Denervation ◽  
Renal Plasma Flow ◽  
Left Kidney ◽  
Extracellular Volume ◽  
Urine Volume ◽  
Urinary Sodium Excretion ◽  
Sodium Reabsorption ◽  
Before And After ◽  
Extracellular Volume Expansion

Sodium reabsorption along the nephron was studied before and after acute unilateral denervation of the left kidney in anesthetized rats with extracellular volume expansion. Studies were also performed before and after sham denervation. Denervation increased urine volume (V) from the left kidney from 35.2 to 59.2 mul min-1 (P less than 0.001) and urinary sodium excretion (UNaV) from 6.9 to 11.8 mueq min-1 (P less than 0.001). The control right kidney showed a simultaneous 45% decrease in V and UNaV. Inulin clearance (GFR) and renal plasma flow (RPF) remained unchanged after denervation in both kidneys. Left kidney late proximal (F/P)m decreased from 1.50 to 1.24 (P less than 0.01); single-nephron GFR (SNGFR) remained unchanged. (F/P)m ratios were also decreased in early distal (3.87–2.65, P less than 0.005) and late distal (5.48–3.83, P less than 0.02) convolutions. Fractional and absolute Na reabsorption in the distal convolution did not decrease. GFR, RPF, V, UNa, late proximal (F/P)m, and SNGFR were unchanged in shamdenervated rats. The increases in V and UNa V produced by acute renal denervation in the volume-expanded anesthetized animal are thus caused by further depression of proximal tubular salt and water reabsorption.

Response to Rapid Volume Expansion During the Postnatal Period

PEDIATRICS ◽  
1981 ◽  
Vol 68 (6) ◽  
pp. 811-813
Author(s):  
Salha S. Daniel ◽  
L. Stanley James ◽  
Jose Strauss
Keyword(s):  
Renal Plasma Flow ◽  
Newborn Infants ◽  
Urine Volume ◽  
Free Water ◽  
Postnatal Period ◽  
Free Water Clearance ◽  
Significant Difference ◽  
Before And After ◽  
The Mean ◽  
The Relationship

The relationship between V, CIN, and CPAH before and during diuresis as a result of infusion of D5W is shown in Figs 3 and 4; the relationship between V, osmolal clearance (COSM), and free water clearance (CH2O) is represented in Figs 5 and 6. The various clearances have been plotted against urine volume and compared with the regression lines for 17 infants (including seven in this paper) during the first three hours of life and prior to receiving an infusion.4 Despite a considerable scatter of data, there is no significant difference in the various correlations before and after infusion. A small decrease in fractional water reabsorption was observed after infusion, but not during spontaneous diuresis. No change in fractional osmolal reabsorption was observed during either spontaneous or infusion diuresis (Tables 2 and 3). In Table 4 the mean changes in the various measurements of renal function measured with infusion are compared with those occurring during spontaneous diuresis in the same infants. Again, except for the percentage of water reabsorbed after the infusion, there were no differences in the responses with the spontaneous diuresis compared to those observed after the infusion. See Images in the PDF File See Images in the PDF File See Images in the PDF File See Images in the PDF File See Table in the PDF File DISCUSSION Newborn infants during the first four hours of life are capable of having a prompt diuresis in response to an infusion of isotonic glucose. This diuresis is accompanied by an increase in renal plasma flow (RPF) and glomerular filtration rate (GFR).

The Effect of Glucose on the Urinary Excretion of Sodium and Hydrogen Ion in Man

1974 ◽  
Vol 47 (6) ◽  
pp. 589-598
Author(s):  
E. S. Garnett ◽  
C. Nahmias
Keyword(s):  
Sodium Excretion ◽  
Normal Subjects ◽  
Urinary Sodium Excretion ◽  
Distal Segment ◽  
Urinary Sodium ◽  
Sodium Ion ◽  
Hydrogen Ion ◽  
Water Diuresis ◽  
Before And After ◽  
Effect Of Glucose

1. Urinary sodium and hydrogen ion excretion was measured in four normal subjects before and after they had ingested 25 g of glucose. The subjects were studied during a sustained water diuresis after an overnight fast and after a 40 h fast. 2. After glucose had been ingested, urinary sodium excretion was reduced by approximately 40% but there was no change in urine flow. The decrease in sodium excretion was associated with a rise in hydrogen ion excretion. 3. These results suggest that sodium ion is retained in exchange for hydrogen ion in the distal segment of the nephron. 4. It is postulated that the increased renal bicarbonate threshold and the metabolic alkalosis which develop when glucose is given to fasted subjects are a consequence of this exchange.

Endothelin-mediated effect of erythropoietin on blood pressure and renal hemodynamics in hypertensive rats

1996 ◽  
Vol 270 (4) ◽  
pp. R744-R748
Author(s):  
A. Tojo ◽  
M. Doumoto ◽  
K. Oka ◽  
A. Numabe ◽  
K. Kimura ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Plasma Flow ◽  
Acute Effect ◽  
Renal Hemodynamics ◽  
Acute Administration ◽  
Dependent Manner ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Before And After ◽  
Wistar Kyoto

Erythropoietin (EPO) has been reported to induce hypertension in hemodialysis patients with family history of hypertension. In this study, to reveal the mechanism of EPO-induced hypertension, we examined the acute effect of EPO on blood pressure (BP) and renal hemodynamics in genetically hypertensive rats, and we also tested the effect of BQ-123, an endothelin ETA-receptor blocker, on EPO-induced changes in hemodynamics. Male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY), aged 9-12 wk, were anesthetized, and BP was monitored through the carotid artery. Renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured before and after an intravenous injection of EPO (1,000 U/kg body wt). In another group of SHR, BQ-123 was continuously infused (1.2 mg.kg body wt-1.h-1) during the experiments. The acute injections of EPO increased BP significantly in SHR in a dose-dependent manner, whereas WKY did not show a significant increase in BP after EPO injections. The effect of EPO on BP in SHR was blocked by BQ-123. In SHR, an acute injection of EPO decreased RPF significantly (from 1.78 +/- 0.16 to 1.49 +/- 0.18 ml.min-1.100 g body wt-1, P < 0.05) without a change in GFR, whereas WKY did not show significant changes in either RPF or GFR. The effect of EPO on RPF in SHR was completely blocked by BQ-123 (from 1.92 +/- 0.26 to 1.88 +/- 0.28 ml.min-1.100 g wt-1, NS). EPO caused a significant increase in plasma endothelin ET-1 in SHR (from 2.3 +/- 0.6 to 6.3 +/- 1.6 pg/ml, P < 0.05), but not in WKY. In conclusion, acute administration of EPO raised blood pressure and reduced RPF in SHR, and these vasoconstrictive effects of EPO are mediated via ETA receptors by an enhanced ET-1 release.

The Effect of Stapedectomy on the Loudness of One’s Own Voice

1965 ◽  
Vol 8 (3) ◽  
pp. 223-234 ◽  
Author(s):  
William Melnick
Keyword(s):  
Middle Ear ◽  
Normal Subjects ◽  
Sound Energy ◽  
Loudness Function ◽  
Before And After ◽  
Increased Sensitivity

Five subjects with normal middle ear mechanisms, and otosclerotic patients, before and after stapedectomy, matched the loudness of their voices to the loudness of a 125-cps-sawtooth noise. The results showed loudness matching functions with gradual slopes, less than 1.00, for the normal subjects and the patients prior to stapedectomy. Post-surgically, the loudness function for the patients increased in steepness to considerably more than 1.00. These results are explained, most logically, in terms of increased sensitivity of the altered middle ear to sound energy generated by the listener’s own voice.

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