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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous in vitro studies of the metabolism of the peripheral nerve have been based on incorporation of radioactive precursor into components isolated from whole nerve. In this study we have determined incorporation secifically into myelin components of peripheral nerve by isolating myelin after incubating whole nerves with lipid or protein precursors and by determining the specific activity of the components of that membrane. The effect of diabetes on such incorporation was also studied. In the rat, in vitro incorporation of DL-[1-14C]leucine into protein components of myelin was decreased by 30-88% in diabetic animals as compared to controls. The major polypeptide constituent of rat sciatic nerve myelin (mol st 28,000; 58.5% of total mass of proteins) was not labeled in either the diabetic or the control group. In diabetes incorporation rate into a polypeptide of mol wt 23,000, which constitutes 21% of total mass, was approximately one half that of controls. In polypeptides of mol wt 38,000-49,000, which are heavily labeled in normal animals, but constitute only about 5% of total mass of proteins, depression of incorporation was e-en more marked in the diabetics. While these marked differences in incorporation between diabetic and control animals were observed, the amount of protein and its distribution among the constituent polypeptides was the same in both groups. In young rats made diabetic with streptozotocin and young rabbits made diabetic with alloxan, there was a lower rate of incorporation of the lipid precursors, [1-14C]sodium acetate or [3H]water, into myelin components. In older animals of both species incorporation in the controls was considerably lower than in the yount animals, and the effect of diabetes was no longer apparent. In nondiabetic animals, the in vitro addition of insulin (10-7 M) stimulated incorporation of DL-[1-14C]leucine into myelin proteins 1.6-3.1 times that of controls. This stimulation by insulin in vitro was not seen in diabetic animals. In animals in which diabetes had spontaneously recovered, however, incorporation rate in the in vitro experiments approached that of controls and were significantly above that in animals whose diabetes persisted. Since myelin is the palsma membrane of the Schwann cell, these studies provide evidence that the Schwann cell is affected by insulin and that some aspects of the metabolism of myelin are altered in insulin-deficient states.
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PMID:Metabolism of peripheral nerve myelin in experimental diabetes. 12 35

Effects of some chemicals, which are known as inhibitors of Ca2+-dependent ATPases, on the water receptor of the frog tongue were examined by using single fungiform papilla preparations. When a sufficient amount of ruthenium red, quinacrine hydrochloride, ethacrynic acid or 2,4-dinitrophenol was added to the standard stimulating solution (5mM CaCl2+100 mM NaCl), which has been shown to stimulate sufficiently the water receptor of the frog tongue, no neural response was elicited. The concentrations necessary for 50% inhibition were approximately 3 X 10(-6)M for ruthenium red, 1 X 10(-5) M for quinacrine hydrochloride, 1 X 10 (-3) M for ethacrynic acid and 2 X 10(-4) M for 2,4-dinitrophenol. Organic mercurials, mersalyl acid and p-chloromercuribenzoic acid, had no effect on the nueral response, but repeated application of these chemicals led to a permanent depression in receptor activity. Ouabain had no effect on either the neural response or receptor activity. These observations indicate that the receptor molecule of the frog water receptor has a similar property to that of the Ca2+-dependent ATPase of red-cell membrane in respect to the susceptibility to inhibitors.
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PMID:Effects of ruthenium red, quinacrine hydrochloride, ethacrynic acid and 2,4-dinitrophenol on the water receptor of the frog tongue. 12 57

Drugs which increase brain levels of serotonin (5-HT) have frequently been found to cause a decrease in voluntary ethanol consumption. Results obtained with parachlorophenylalanine (pCPA), which decreases 5-HT, have been less consistent. The present investigation compared the effects of pCPA on alcohol selection with those of pargyline, a monoamine oxidase inhibitor which increases brain levels of 5-HT. Ingestion of a 10% ethanol solution was assessed in male C57BL/6J mice given daily injections of 250 or 300 mg/kg pCPA, 50 mg/kg pargyline, or saline. An additional control group received no treatment. A two-bottle preference procedure was employed, and ethanol and water intake were recorded during a pretreatment period (11 days), a treatment period (8 days), and a posttreatment period (10 days). Like other agents which increase 5-HT, parygyline produced a depression in ethanol intake which lasted beyond the time of drug administration. pCPa had no effect on ethanol ingestion either during the period of drug administration or afterwards.
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PMID:Reduction of alcohol selection by pargyline in mice. 13 69

Variations in epidermal chalones after a single surface application of methylcholanthrene have been described in previous papers. This paper reports a study of the effect of croton oil on epidermal growth regulators (G1 and G2 chalones). Hairless mice received a single topical application of 0.2 ml 0.25% acetone solution of croton oil. Control mice received only acetone. The short-term effect of croton oil on epidermal DNA synthesis and mitotic rate was studied. Other groups of croton oil-treated and acetone-treated mice were then killed at similar time intervals, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal DNA synthesis and mitotic rate was assayed in normal hairless mice. The resulting inhibition was interpreted as an expression of the concentration of G1 and G2 chalones, respectively, in the skin extracts. The first experiment confirmed that a single croton oil application provokes a short block in epidermal mitotic activity and probably also in DNA synthesis. This was followed by bimodal peaks of increased activity, the two maxima of mitotic rate on days 2 and 7. The concentration of the two chalones in the skins of treated animals varied in inverse proportion to the alterations in the DNA synthesis and the mitotic rate, with one exception. There was here initially a depression both of the mitotic rate and a low concentration of G2 chalone. This was interpreted as a short, initial direct effect of croton oil on the G2 chalone present at the time of application. It is concluded that croton oil application injures and kills epidermal cells, with subsequent alterations in the content of G1 and G2 chalones. This theory may explain the changes observed. The effects of croton oil on the amount of G1 and G2 chalones in the skin are probably related to the direct, toxic, cell-killing effect of croton oil, and not to its specific cancer promoting potency.
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PMID:Effects of croton oil on epidermal growth regulators (chalones). 13 13

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

In Goldblatt rats (GV) 4-24 weeks after coarctation of one renal artery the following characteristics were registered as compared to controls (CV) of the same age: Arterial blood pressure increased to 190-200 mmHg in comparison to 105-110 mmHg in controls. This pressure overload induced an increase in ventricular weights (34%-54%). Noteworthy differences in myocardial water, total protein, and nonprotein substance contents were found. Hydroxyproline concentration in GV did not increase significantly until 24 weeks after onset of pressure overload. No significant alterations were detected in the relationship of myocardial, sarcoplasmic, and stromal protein fractions. However, greater changes could be registered in the concentration of the myofibrillar protein fraction and its single components. Furthermore, a correlative depression in specific actomyosin ATPase activity and in maximum shortening velocity of the unloaded cardiac muscle (2,3) was observed.
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PMID:Characteristics of the hypertrophied left ventricular myocardium in Goldblatt rats. 14 Jun 72

Variations in epidermal chalones after a single surface application of methylcholanthrene and croton oil have been described in previous papers. This paper reports a study of the effect of adhesive tape stripping of the skin on epidermal growth regulators (G1 and G2 chalones). Pieces of adhesive tape were applied 6 times to the same area of skin in groups of mice. The short-term effects of tape stripping on epidermal DNA synthesis and on mitotic rate were studied at different intervals after stripping. Other groups of mice were killed at similar time intervals after stripping, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal DNA synthesis and mitotic rate was assayed in normal hairless mice. The resulting inhibitions were interpreted as an expression of the concentration of G1 or G2 chalone in the skin extracts. The first experiment confirmed that cellophane tape stripping gives rise to a short block in epidermal mitotic activity and probably also in DNA synthesis. This was followed by bimodal peaks of increased activity, the two maxima of labelling index being found on days 2 and 6, and the two maxima of mitotic rate on days 1-2 and 7. The concentrations of the two chalones in the skins of treated animals varied in inverse proportion to the alterations in the DNA synthesis and the mitotic rate, with one exception. Here there was initially a depression of the mitotic rate and a low concentration of G2 chalone. This was interpreted as a short reaction of the basel cells to the stripping trauma. It is concluded that adhesive tape stripping removes the differentiating cells and injures some basel cells, simultaneously altering the content of G1 and G2 chalones. The resulting increase in the rates of DNA synthesis and mitosis lasts only until the number of cells is high enough to produce growth-regulating substances (chalones) again. This theory may explain the changes observed. Since similar reactions are seen after both carcinogenic and co-carcinogenic chemical injury of the epidermis, the reaction pattern seems to be a general response to cell injury or cell removal.
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PMID:Effects of cellophane tape stripping of mouse skin on epidermal growth regulators (chalones). 14 79

In experiments on isolated gallbladders (GB) of frogs it was established that noradrenaline in concentration of 6.10(-9)--3.10(-4) M acting on the organ from the serosalsurface causes firstly a short increase and then -- a prolonged inhibition of the absorption rate of NaCl -- isotonic fluid from the gall bladder cavity. While the concentration of the mediator increases in the inculation medium, its inhibiting effect increases too. Depression, and at high concentration in the medium, full inhibition of the process of fluid absorption is accompanied with distinct decrease of Na--, K--ATPase activity of gall bladder epithelial cells. Mediator in concentration of 3.10(-8) M caused an increase of membrane potential of the epithelial cells, while its increasing in the inculation medium to 3.10(-6) M caused a decrease of the transmembrane potential difference. Under the noradrenaline influence the increase of the osmotic permeability of the gall bladder's wall for the water flow directed from the mucosa to the serosalsurface of the organ took place, and also the decrease of the wall's permeability for the water flow in the opposite direction was seen. It was concluded that the noradrenaline inhibitory action on the process of absorption of NaCl--isotonic fluid from the gall bladder cavity was observed because of the decrease of the Na--K--ATPase activity, and also because of the change of the permeability of epithelium for the passive ion and water transport.
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PMID:[Effect of noradrenaline on ion and water transport through frog gall bladder epithelium]. 15 53

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

Water-perfused thermodes were chronically implanted around the preoptic nuclei and hypothalamus (POH) of kangaroo rats (Dipodomys ingens). Responses in rate of metabolic heat production to manipulations of POH temperature (Thy) were measured in unanesthetized, unrestrained animals at ambient temperatures of 10, 20, 25, and 30 degreeC. The threshold Thy and the proportionally constant (alpha) for this response consistently decreased as ambient temperature increased, but alpha was not significantly different between any two Ta's. Average values of alpha for the three animals studied ranged between -.0024 W.g minus 1.degree C minus 1 and -.0034 W.g minus1.degree C minus 1. No influence of extrahypothalamic core temperature on the characteristics of the central nervous system regulatory mechanism was observed. Ahypothesis accounting for high POH and low peripheral thermosensitivities in small mammals is presented. An additional finding was that during sleep there is a profound depression or elimination of POH thermosensitivity in this species.
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PMID:CNS regulation of metabolic rate in the kangaroo rat Dipodomys ingens. 16 86


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