Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using micropuncture techniques, the author studied the effect of vasopressin on renal function in young rats at three stages of development -- in the middle of the weaning period (22 days), after weaning was over (30 days) and at the beginning of the sexual maturation period (42 days). In the presence of a hypotonic load, a small dose of vasopressin (12 muU/100 g b.w., i.v.) was most effective in the youngest age group, where it reduced the urine flow by 82% both by increasing water reabsorption and by reducing the GFR. In this group, vasopressin lowered the TF/P Na+ ratio and raised the TF/P K+ ratio in the initial part of the distal tubules of the superficial nephrons, but raised water absorption only beyond the initial part of the distal tubules. Vasopressin reduced the urine flow by 72% in 30-day-old rats by raising water reabsorption beyond the initial part of the distal tubules. The only ion to be affected was K+, whose concentration rose in the final urine. In 42-day-old rats the effect of vasopressin was manifested in only mild depression of the GFR. In this age group, as distinct from younger animals, anaesthesia and surgery evidently led to endogenous vasopressin release, so that the small dose of exogenous vasopressin did not significantly influence the test parameters. This is also underlined by the significant difference between the control urine flow of the 42-day-old and the younger rats.
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PMID:The effect of vasopressin on renal function in young rats a clearance and micropuncture study. 13 28

Lithium (Li+) chloride, 2 to 3 mEq. per kilogram of body weight, was administered intraperitoneally to normal Wistar rats daily for 4 to 66 days. This resulted in a marked reduction in urine osmolality (Uosm.) and increase in the excretion of water, Na+, K+, uric acid, and phosphate. The excretion of uric acid and potassium was a direct function of UNaV. The magnitude of depression in urine osmolality was significantly related to the rate of excretion of lithium in the urine, suggesting that the change in water reabsorption is dependent on the presence of the ion in the luminal side of the tubule. During 2 per cent saline diuresis, Li+-treated rats achieved less fractional free water reabsorption (TcH2O/GFR times 100) at any level of fractional osmolar clearance (Cosm./GFR times 100) than normal rats. On the other hand, during 0.225 per cent saline diuresis, fractional free water clearance (CH2O/GFR times 100) was normal over a wide range of fractional urine flow (V/GFR times 100), indicating intact function of the ascending limb of the loop of Henle. The intravenous infusion of vasopressin (VP) or dibutyryl cyclic-adenosine monophosphate (dcAMP) to Li+-treated rats resulted in a modest rise in Uosm. and a reduction in V/GFR times 100 and CH2O/GFR times 100. Although the response to VP appeared earlier than that to dibutyryl cyclic-AMP, the magnitude of the changes in Uosm., V/GFR times 100, and CH2O/GFR times 100 was eventually the same with both substances. Comparison between normal and Li+-treated rats revealed that the response to both VP and dibutyryl cyclic-AMP was blunted, albeit to a greater extent in the former. Inhibition by Li+ of adenylate cyclase will only partially explain the present data. Impairment in the release of endogenous VP or a block distal to the formation of cyclic-AMP must have played a role. In view of a normal diluting capacity and the increase in the excretion of phosphate and uric acid, it is suggested that Li+, when administered chronically in the present doses, inhibits proximal tubular reabsorption.
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PMID:Renal effects of lithium administration in rats: alterations in water and electrolyte metabolism and the response to vasopressin and cyclic-adenosine monophosphate during prolonged administration. 16 79

The effects of acute i.v. inorganic phosphate (Pi) loading were studied on nembutalized mongrel dogs previously subjected to unilateral splanchnicotomy ("renal denervation"). GFR (51Cr-EDTA) was not different on the intact and the denervated side, while urine output (V), sodium excretion (UNaV), and urinary excretion (UPiV) of inorganic phosphate of denervated kidneys were significantly increased at any plasma Pi level. Thus, tubular reabsorption of Pi in denervated kidneys was considerably depressed. Tubular transport rates of Na and Pi--as expressed in per cent of the filtered load--were positively correlated in both intact and denervated organs. Besides an impairment in tubular transport of Na a depression in the reabsorption of inorganic phosphate is brought about by renal denervation. A common mechanism of action for both Na and Pi can be supposed.
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PMID:Effect of splanchincotomy on the renal excretion of inorganic phosphate in the anaesthetized dog. 55 51

1. The influence of partial hepatectomy on urinary concentrating ability and renal tissue sodium was determined in conscious rats deprived of water for 24 h. In comparison with a sham operation, partial hepatectomy resulted in: a) a 50% reduction in free-water reabsorption, urinary osmolality, and osmolal urine-to-plasma ratio; b) depression of free-water reabsorption at similar levels of osmolal clearance above 200 microliter/min per ml of GFR during the infusion of hypertonic NaCl and vasopressin; and c) a 30% reduction in sodium content of the renal papilla and outer medulla. 2. The renal response to an intravenous water load (2.5% glucose infused to 2.5% of body wt at 0.4 ml/min) was determined in sham-operated and partially hepatectomized, conscious rats. By 60 min after the water load, both groups had excreted practically all of the load. However, during and for 30 min after the infusion in the partially hepatectomized group, the percent of the water load excreted, urine flow, and free-water clearance were significantly reduced while urinary osmolality and osmolal urine-to-plasma ratio were significantly elevated. 3. These experiments demonstrate that shortly after partial removal of the liver the renal concentrating ability is defective and the excretion of a water load is not grossly impaired.
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PMID:Concentration and dilution of the urine in partially hepatectomized, conscious rats. 56 70

We have studied sodium retention during volume expansion in rats with autologous immune complex nephropathy (AICN), a model of nephrotic syndrome (NS) in which GFR after volume expansion was not different from that in adjuvant-injected controls (C). AICN rats developed heavy proteinuria (298 +/- 27 vs. less than 10 mg/day), hypoalbuminemia (2.14 +/- 0.15 vs. 3.08 +/- 0.12 g/100 ml) and hypercholesterolemia (181 +/- 22 vs. 58 +/- 4 mg/100 ml). After saline, there were no significant differences in blood pressure (119 +/- 2 vs. 114 +/- 2 mm Hg), renal plasma flow (4.9 +/- 0.41 vs. 4.1 +/- 0.28 ml/min), inulin clearance (1.37 +/- 0.06 vs. 1.55 +/- 0.10 ml/min), or SNGFR (47 +/- 2 vs. 53 +/- 4 nl/min). Sodium excretion, however, was significantly lower in NS rats (4.7 +/- 1.1 vs. 9.2 +/- 1.2 muEq/min). Proximal sodium reabsorption was decreased in NS rats (35 +/- 2 vs. 41 +/- 2%, 2.5 +/- 0.2 vs. 3.3 +/- 0.2 nEq/min). Sodium delivery into the loop, however, was equal in NS and C, since the slightly lower filtered load in NS rats offset the depression in proximal reabsorption. Sodium reabsorption by the loop and by the distal convoluted tubules were equal in NS and C. Thus, sodium delivered into the cortical collecting ducts was the same in both groups (0.33 +/- 0.17 vs. 0.34 +/- 0.07 nEq/min; 4.5 +/- 0.6% of filtered sodium vs. 4.4 +/- 0.3%). The percent of filtered sodium excreted in the urine, however, was significantly lower in the NS rats, 2.18 +/- 0.48% vs. 4.0 +/- 0.58%. We conclude that antinatriuresis in this model of NS is determined beyond the superficial late distal convoluted tubule. The inability to excrete the sodium load during volume expansion is due to either enhanced reabsorption by the collecting duct or to abnormal function in deep nephrons.
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PMID:Renal sodium retention during volume expansion in experimental nephrotic syndrome. 75 Jun 93

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 sham-denervated 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.
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PMID:Acute unilateral renal denervation in rats with extracellular volume expansion. 83 10

Whether volume expansion influences NaC1 reabsorption by the diluting segment of the nephron remains a matter of controversy. In the present studies this question has been examined in normal unanesthetized dogs, undergoing maximal water diuresis. Free water clearance (CH2O/GFR) has been used as the index of NaC1 reabsorption in the diluting segment. Three expressions have been employed for "distal delivery" of NaC1: a) V/GFR, designated as the "volume term"; b) (CNa/GFR + CH2O/GFR), the "sodium term;" and c) (CC1/GFR + CH2O/GFR), the "chloride term". The validity of these terms is discussed. Three techniques were used to increase distal delivery: 1) the administration of acetazolamide to dogs in which extracellular fluid (ECF) volume was not expanded (grop 1); 2) "moderate" volume expansion (group 2); and 3) "marked" volume expansion (group 3). CH2O/GFR increased progressively with rising values for "distal delivery" regardless of which term was used to calculate the latter. With all three delivery terms, differences in distal NaC1 reabsorption emerged between the two volume-expanded groups, though only with the "chloride" term did substantial differences also emerge between the nonexpanded group 1 dogs and both volume-expanded groups. In group 1, values for CH2O/GFR increased in close to a linear fashion up to distal delivery values equal to 24% of the volume of glomerular filtrate. However, at high rates of distal delivery the rate of rise of CH2O/GFR was less in group 2 than in group 1 and the depression of values was even greater in group 3. Within the limits of the techniques used, the data suggest that volume expansion inhibits fractional NaC1 reabsorption in the diluting segment of the nephron in a dose-related fashion. The "chloride" term was found to be superior to the "volume" and "sodium" terms in revealing these changes.
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PMID:Influence of volume expansion on NaC1 reabsorption in the diluting segments of the nephron: a study using clearance methods. 97 43

The role of protein kinases in renal noradrenergic stimulation was examined using sphingosine, 1-(5-isoquinolinylsulfonyl)-2-methyl-piperizine (H7), using sphingosine, 1-(5-isoquinolinylsulfonyl)-2-methyl-piperizine (H7), or staurosporine to inhibit the responses to norepinephrine (NE, 60 nM) in isolated perfused rat kidneys. Sphingosine (20 mumol/L) increased the noradrenergic vasoconstrictor response. H7 (10 mumol/L) partially blocked the immediate vasoconstrictor response and completely inhibited it after 2 min without altering the antinatriuretic and antilithuretic responses. H7 also blocked the increase in free water produced by NE, which is consistent with the inhibition of protein kinase A linked to beta-adrenergic stimulation. Staurosporine (10 nmol/L) partially inhibited noradrenergic vasoconstriction and antinatriuresis, and it completely blocked the depression of gluconeogenic responses to NE in pyruvate-perfused kidneys. To examine the role of diacylglycerol and protein kinase C in the renal responses to NE, we used oleoyl-acetyl-glycerol (OAG, 50-100 microM) or phorbol-12-myristyl-13-acetate (TPA, 5-50 nM). TPA slowly vasoconstricted the kidney and reduced GFR and fractional Na+, Li+, and free water excretion. Amiloride (1 mM) prevented the TPA responses. OAG mimicked the effects of TPA except that vasoconstriction occurred more rapidly and was brief. Both TPA and OAG acted like alpha 1-adrenergic agonists. These results indicate that diaclyglycerol and protein kinase are involved in the prolonged effects of NE on vasoconstriction. GFR, and proximal tubular reabsorption.
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PMID:Diacylglycerol and protein kinase mediated noradrenergic responses in perfused rat kidneys. 239 Jul 42

Affective illness is common, frequently debilitating, and sometimes life-threatening in the elderly. Considerations pertaining to treatment with heterocyclic drugs, MAOIs, lithium, psychostimulants and thyroid hormone, as well as ECT, have been reviewed. Amitriptyline and imipramine cause significant orthostatic hypotension and probably should be avoided in the elderly. In addition, amitriptyline is extremely anticholinergic. Amoxapine is essentially a neuroleptic sequelae, including tardive dyskinesia. If a patient has had a prior positive response or has a relative who had a good outcome from a particular drug, it may be best to begin treatment with that drug. Initial choice of antidepressant can be based largely on the clinical picture. For example, if a depressed patient is sleeping much more than usual, try a potentially activating agent like desipramine or protriptyline. if, on the other hand, the patient is unable to sleep, a more sedating agent like nortriptyline, maprotiline, trimipramine, or trazodone should be tried. Risks and side effects of these drugs, as well as their use in cardiac patients, have been reviewed in detail. Many clinicians avoid MAOIs in elderly patients because of fear of adverse reactions. This fear is largely unfounded. Precautions, side effects, and specific recommendations have been outlined. Using lithium in the elderly requires special precautions because of decreased GFR and potential interactions with concomitantly used drugs. This paper has discussed possible side effects and toxicity. The usage of psychostimulants, such as methylphenidate and amphetamine, to treat medically ill depressed patients is reviewed. These agents are also sometimes useful in demented individuals or in patients with abulic frontal lobe syndromes. Poststroke depressions are common, and recent evidence indicates that they can be adequately treated. Stroke patients have many difficulties dealing with rehabilitation and should not be forced to suffer concomitant depression when we have the tools at hand to effectively treat such symptoms. Recent data on the potentiation of antidepressant effects by lithium or T3 indicate that they may be useful adjuvants in some tricyclic-resistant patients. Risks, side effects, and recent procedural advances in the use of ECT have been reviewed. Electroconvulsive therapy is both more effective and faster-acting than drugs in the treatment of depression. Many depressed elderly patients, especially those with psychotic symptoms, do not respond to drugs but improve with ECT.
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PMID:Treatment of affective illness in the elderly with drugs and electroconvulsive therapy. 269 55

The ontogenetic renal responsiveness to exogenous cortisol was examined in the chronically cannulated ovine fetus. The contribution of effects at proximal and distal tubule of the kidney were studied also. Cortisol (81.5 micrograms/h) was infused into immature ovine fetuses (mean gestational age -113.9 days) on five occasions and increased blood cortisol from 0.8 +/- 0.5 to 21.3 +/- 6.2 nmol/liter. This dose of cortisol produced a highly significant diuresis and natriuresis, in part due to an increase in GFR and in part due to a significant decrease in proximal tubular reabsorption of sodium. Cortisol (107.2 +/- 4.7 micrograms/h) was infused into mature fetuses (mean gestational age 133.4 days) and produced an increase in blood cortisol concentration from 11.4 +/- 5.6 to 33.7 +/- 6.8 nmol/liter. No natriuresis or diuresis was seen in the mature fetuses. Cortisol caused a significant depression of proximal tubular sodium reabsorption in mature fetuses, but this extra load was reabsorbed in the distal tubule in these fetuses. The inability of the premature or very low birth wt baby to maintain normal sodium balance on a standard salt intake may be due, at least in part, to a "fetal" renal response to the high plasma cortisol concentrations found in such babies. As the kidney matures it becomes capable of increasing distal tubular sodium reabsorption to compensate for any increased distal tubular fluid delivery.
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PMID:Gestational changes in renal responsiveness to cortisol in the ovine fetus. 277 10


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