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)

To investigate the effect of fluoralkanes on cellular functions, isolated frog muscles were exposed to octafluoro-pentanoic acid (OP) and hexadecafluoro-nonanoic acid (HN). 20 MM of OP induced a small depression of the contraction amplitude and a loss of wet weight of 10% which was similar to the osmotic effect of pentanoic acid or sucrose. The membrane resting potential was not changed up to 50 mM. HN was much more effective: 0,5 mM decreased the contraction amplitude in a few minutes and depolarized the membrane by 20 to 30 mV in 2 h. 10 mM HN induced a weight gain of 20% connected with a contracture. Since the caffeine contracture was also depressed by 1 mM it is assumed that HN interact with cellular membranes and alter their Ca-binding properties.
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PMID:[Effect of omega-H-perfluorinated carbonic acids on the wet weight, membrane potential and contractility of isolated skeletal muscle]. 74 60

(+)-Amphetamine and fenfluramine depressed both the food intake during the first 2 h of feeding of mice adapted to feed between 12:00 and 15:00 daily and the food intake of free feeding mice between 24:00 and 02:00 (lighting on, 09:00-21:00) in a dose-dependent manner. Higher doses of each drug were needed to produce a significant depression in the latter case. However, (+)-amphetamine (0.5-2 mg/kg) markedly increased the negligible food intake of free feeding mice between 12:00 and 14:00, an effect which rapidly disappeared at higher doses. Fenfluramine at doses up to 40 mg/kg had no effect on the feeding of these mice. Nevertheless, as caffeine (10-40 mg/kg) also increased feeding, behavioural arousal might be an important factor in this anomalous feeding response, although a specific action by (+)-amphetamine and caffeine on the feeding centres of the satiated mouse cannot be ruled out.
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PMID:The effects of (+)-amphetamine and fenfluramine on feeding in starved and satiated mice. 82 84

This study describes the effect of hypertonic solutions on isolated muscle fibers of Callinectes danae. Solutions of twice normal tonicity (2.0 T) inhibit both the normal graded membrane responses and the spikes induced by procaine, tetraethylammonium, or barium. The inhibition is maintained throughout exposure to hypertonic solutions prepared by addition of impermeant solutes such as NaCl, sucrose, or Tris-propionate, but is reversible on their withdrawal. In the presence of permeant solutes such as glycerol or acetamide, the inhibition is transient. In both cases the onset of inhibition of the depolarizing Ca electrogenesis is correlated with shrinkage of the fiber. In the case of permeant solutes, the time course of recovery of the graded responses or the spikes follows the recovery of the fiber volume. Changes in the passive electrical characteristics of the fibers due to hypertonic solutions were unrelated to the blockade of membrane Ca activation. The current-voltage relationship in hypertonic sollution revealed no increase in depolarizing K activation. Inhibition of the graded membrane responses and spikes appears to be associated with depression of Ca conductance. Hypertonic solutions might affect the activation of Ca conductance through reduction of the electric field generated by fixed negative surface charges and/or morphological changes in the T tubules. Membrane depolarization elicited little or no tension in 2.0 T solutions while caffeine contracture (10 mM) with an ampliture of 76% of the maximal contractile ability could still be elicited. This indicates that direct effects of hypertonic solutions on the contractile apparatus were not responsible for loss of tension. The latter is attributed to the inhibition of the transmembrane Ca currents.
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PMID:Inhibition by hypertonic solutions of Ca-dependent electrogenesis in single crab muscle fibers. 91 72

Isolated isometric ventricular muscle of frogs and cats was studied. Perfusing solutions were played directly on the muscle to permit rapid exchange of the extracellular space. Developed force and maximal rate of rise of force were measured in all studies and action potentials (AP) were recorded in some. For both species low concentrations of ethanol (75 degrees mg/l) potentiate contraction. Higher concentrations ( greater than or equal to 750 mg/l) depress contraction progressively with increasing concentration. Concentrations which depress contraction, e.g., 3-4.5 gm/l, usually shorten AP duration. The shortening of AP duration can occur even though contractile force does not fall and, conversely, force may fall while AP duration is unaffected. When 10 mM caffeine is added to the perfusate of either species, AP duration is prolonged and contraction is potentiated. If both ethanol (4.5 gm/l) and 10 mM caffeine are added simultaneously to the perfusate, there is a rapid (within 4 beats) increase in AP duration and an initial depression of contraction, followed by a further increase in AP duration and a significant potentiation of contraction. The steady state contraction is less than with caffeine alone. These preliminary studies suggest that ethanol may depress contraction both by shortening AP duration and by a direct effect upon the contractile apparatus.
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PMID:The action of ethanol upon the action potential and contraction of ventricular muscle. 108 Dec 55

Substitution of ammonium ions for sodium ion initially potentiated and then depressed twitch tension of the frog sartorius muscle. The extent of potentiation and the rate of depression of the twitch were dependent upon the concentration of ammonium ions. Ammonium ion depolarized individual muscle fibers in proportion to concentration. Maximum depolarization (33 mV) occurred in muscles equilibrated in 120 mM ammonium-Ringer for 30 min. At the higher concentration of ammonium (72--120 mM), the potentiation was quickly reversed and the tension response was eliminated completely. The gradual loss of twitch tension was accompanied by progressive decrease in the electrical excitability of individual muscle fibers. Raising the extracellular calcium concentration fivefold reduced the twitch-depressant effect of ammonium ions by maintaining excitability of the muscle fibers. Caffeine contractures (3 and 10 mM) in muscles preequilibrated in 72 mM ammonium-Ringer developed similar tensions to paired controls muscles, but the onset of tension was more rapid in the ammonium-treated muscle. It was concluded that the depression of tension could be accounted for by the loss of membrane excitability and that the evidence did not support the hypothesis that ammonium ions acted at other sites in the excitation contraction coupling.
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PMID:Influence of ammonium ions on mechanical and electrophysiological responses of skeletal muscle. 108 37

1. The contractility of isolated muscles of the frog (and in some instances of the rat) was investigated at room temperature in Ringer's solutions containing homologous alkanoic acids (100 mM C4 to 0.4 mM C10). 2. Free fatty acids decrease the contraction amplitudes evoked by direct stimulation. The effects increase with concentration, exposure, and chain length of the fatty acids. In Ringer's solution the changes are totally or partly reversible. 3. The depression of contraction amplitude induced by free fatty acids is removed by small concentrations of caffeine (2--5 mM) in Ringer's solution. 4. Interactions of fatty acids with different structures of skeletal muscle (mitochondria, sarcolemma and membranes of sarcoplasmic vesicles) are discussed. The distinct effect of fatty acids on stimulated muscles and the importance of membranes in the regulation of the calcium ion concentration in the cytoplasm suggest that fatty acids interact with membrane lipids.
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PMID:[Influence of homologous n-alkanoic acids on functional properties of isolated skeletal muscles. I. Muscle contraction]. 108 27

The effects of methylazoxymethanol (MAM) acetate on colony survival, cell proliferation and DNA synthesis of murine lymphoma L5178Y cells are studied. Decreased sensitivity and immediate depression of cell proliferation and DNA synthesis were found in L5178Y cells in contrast to the reports on HeLa cells. Pre-labelling with 5-bromodeoxyuridine (BUdR) did not enhance significantly the carcinogen-induced cell lethality. Post-treatment with caffeine greatly enhanced cell lethality and depression of cell proliferation. These effects of caffeine were diminished when the cells had passed through two generations following the MAM acetate treatment. Experiments with synchronized cells showed that the action of caffeine was located primarily in S phase following the MAM acetate-treatment. These results strongly suggest that in L5178Y cells, MAM acetate induces damage, which is repaired by a mechanism analogous to post-replication repair of UV light-induced damage.
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PMID:Evidence for caffeine-sensitive damage in methylazoxymethanol acetate-treated L5178Y cells. 124 56

Panic episodes were described as a distinct form of anxiety by Freud almost 100 years ago, and the recent publication of the Diagnostic and Statistical Manual of Mental Disorders, third edition (D.S.M.-III), has provided the basis for the separate diagnostic entity of panic disorder. In this study, we showed the historical review of research and the result of our clinical study of panic disorder in 7 patients. The following results were obtained: 1) Abnormal DSTs were observed in only two of 5 patients. 2) Five of 6 patients showed high concentration of adrenaline and noradrenaline in urine. 3) Anxiety was provoked by caffeine in two of 5 patients. 4) Depression of T-wave was shown in three of 5 patients with orthostatic E.C.G. 5) Sinus tachycardia was gained in one of 3 patients with Holter E.C.G. 6) Abnormal respiratory functions were observed in all two patients with Treadmill. 7) Only one small heart was observed on a chest radiograph. 8) Panic attacks were provoked by sodium lactate infusion in four of 7 patients.
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PMID:[Panic disorder]. 128 52

1. Single fibres isolated from the anterior tibialis muscle of Rana temporaria (temperature, 2-5 degrees C; sarcomere length, 2.10 microns) were fatigued using two separate protocols that led to different degrees of depression of tetanic force. Under control conditions the fibre was stimulated to produce a 1 s fused isometric tetanus at 300 s intervals. A moderate degree of fatigue (tetanic force reduced to 70-80% of the control value) was produced by decreasing the intervals between tetani to 15 s ('fatiguing protocol 1'). A more pronounced depression of tetanic force (to 40-50% of the control value) was produced by evoking a single twitch at 1-2 s intervals ('fatiguing protocol 2'). 2. Fatiguing protocol 1 reduced the contracture response to submaximal and supramaximal concentrations of caffeine (3-15 mM) in proportion to the decrease in tetanic force. These results support the view that fatiguing stimulation according to protocol 1 leads to a true 'myofibrillar fatigue' with no failure of activation of the muscle fibre. 3. Fatiguing protocol 2 reduced the amplitudes of isometric twitch and tetanus to below 10 and 50% of the control values, respectively. By contrast, the maximal contracture response to caffeine (15 mM) was depressed by merely 2-3% of its prefatigue value. 4. Force and instantaneous fibre stiffness were recorded simultaneously during twitch and tetanus as fatigue was induced by protocol 2. During the initial part of fatigue (tetanic force reduced by 25% of control) stiffness was reduced by merely 9% in accordance with previous measurements during fatigue induced by protocol 1. However, with further depression of twitch and tetanus by protocol 2 there was a marked reduction of fibre stiffness. These results, together with the findings reported under point 3, strongly suggest that at an advanced state of fatigue induced by protocol 2 the decrease in active force is largely due to failure of activation of the contractile system. 5. Muscle fibres were quickly frozen for electron microscopical examination after shortening below slack length (to approximately 1.6 microns sarcomere spacing) during tetanic stimulation. In non-fatigued fibres, and in fibres fatigued according to protocol 1, the myofibrils exhibited a straight appearance throughout the preparation suggesting that the entire volume of the fibre was properly activated. In fibres fatigued by protocol 2, on the other hand, only the most peripheral layers of myofibrils remained straight after shortening, whereas the centre of the fibre showed marked waviness indicating failure of the inward spread of activation in this case.
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PMID:Myofibrillar fatigue versus failure of activation during repetitive stimulation of frog muscle fibres. 129 47

Self-reported and observer-rated signs and symptoms of nicotine withdrawal were assessed precessation and 2, 7, 14, 30, 90, and 180 days postcessation in smokers who quit on their own for 30 days. Anxiety, difficulty concentrating, hunger, irritability, restlessness, and weight gain increased, and heart rate decreased, postcessation (p less than .001). Except for hunger and weight gain, these symptoms returned to precessation levels by 30 days postcessation. Craving, depression, and alcohol or caffeine intake did not reliably increase. Postcessation depression, but not withdrawal symptoms, craving, or weight gain, predicted relapse. These results are consistent with prior studies.
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PMID:Tobacco withdrawal in self-quitters. 140 84


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