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)

The actions of three intravenous anaesthetics, Althesin, thiopentone and ketamine have been compared on the rat isolated atria and portal vein. Although the three anaesthetics had grossly similar actions on the two preparations. i.e. depression of atrial rate and depression of the amplitude of myogenic activity in the portal vein, there were enough differences to suggest that they produced their effects by different mechanisms. These differences were particularly obvious in interactions with noradrenaline and the effects of changes in calcium ion concentration on the concentration effect relationships for the agents on the atria and portal vein. Generally Althesin was unaffected by changes, but in qualitatively different ways.
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PMID:An in vitro study of the effects of calcium on the cardiovascular actions of thiopentone, althesin and ketamine in the rat. 3 16

Spontaneous miniature junctional potentials and induced by motor nerve stimulation junctional potentials were recorded in muscle fibres of the third instar Drosophila larvae. Presynaptically active neurotoxins isolated from the snake venoms (beta-bungarotoxin 4.5 x 10(-7) M, notexin and notechis-II-51 X 10(-7) M, Crotoxin 9 x 10(-8) M, phospholipase from the venom of cobra 4 x 10(-6) M did not induce any changes in transmitter release during 60--120 min of contact with Drosophila preparation, although these concentrations exceed those used in frog or mice preparations. On the contrary, bee venom phospholipase (1.25 x 10(-7) M) turned out to be even more active than in frog or mice junctions. A similar sequence of three phases of the presynaptic blocking effect was found: initial decrease followed by a period of increase and finally -- depression of both spontaneous and evoked release. Bee venom phospholipase was ineffective in Ca2+-free solution but its irreversible binding to nerve endings took place evidently in spite of Ca lack.
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PMID:[Effect of neurotoxins on mediator release from the motor nerve endings of the Drosophila melanogaster larva]. 4 40

After exposure of sexually immature chickens to lindan in doses of 2.5 to 25.0 mg kg-1 of feeds, the effect of the insecticide on the biological activity of estradiol was investigated. The changes in the effectiveness of estrogen, expressed by an increase of the mass of the oviduct and of the level of serum calcium, were evaluated by means of comparison of animals exposed to the insecticide with a control group that had been applied only the standard hormone dose. Proofs were obtained for the fact that the application of lindan in the quantity of the mentioned doses for 14 days caused a statistically conclusive depression of the biological effectiveness of estrogens. Compared with the control group, the stimulated mass of the oviduct of animals exposed to the insecticide was smaller by 12.7 to 17.1 p. c. and the average concentration of the serum calcium decreased by 8.0 to 27.6 p. c. The results obtained indicate that the influence of lindan already in relatively low concentrations caused significant changes in the effectiveness of exogenous estrogens.
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PMID:[Effect of lindane on the biological effectiveness of estradiol in chickens]. 5 34

70 chronic alcoholics in the withdrawal state, 45 with convulsions and 25 controls without convulsive seizures, were tested with respect to electrolyte changes and acid base balance in serum or blood and cerebrospinal fluid (CSF). It was of special interest to note that there was a partial independence between magnesium levels in serum and CSF. Thus the serum level has only a limited liability as to magnesium depletion suggested to be responsible for seizure precipitation. In the seizure group a slightly but significantly lower magnesium, potassium and calcium in CSF and a significant decrease of potassium and calcium in serum were revealed. In the nonzeizure controls a similar decrease of magnesium in serum and potassium in CSF was observed while serum potassium and calcium in CSF and serum remained in low normal range. In both groups there was a prominent respiratory alkalosis. The role of magnesium depression for seizure precipitation is discussed with respect to the concomitant changes of other electrolytes and acid base disturbances.
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PMID:Electrolyte changes and acid base balance after alcohol withdrawal, with special reference to rum fits and magnesium depletion. 6 5

Four patients without symptoms of episodic hyperkalemic weakness from two families with paramyotonia congenita (Eulenburg) are described. 1. Maximum voluntary muscle contraction of the upper and lower arm was studied under isometric conditions at different temperatures. If the temperature was lowered stepwise, distinct paresis occured at 32--31 degrees C which increased with the amount of muscular effort. The upper arm muscles, however, developed weakness gradually after cooling. 2. During cooling of the resting muscle, the EMG showed dense spontaneous activity of the fibrillary type, which decreased again at about 30 degrees C. It can be assumed that in paramyotonia congenita cooling produces muscle cell membrane depolarization which at a critical level causes the firing of action potentials and finally muscular paresis. 3. Increasing muscular stiffness can be interpreted as abnormally slow muscular relaxation after isometric contraction. In the forearm muscles the time to 3/4 relaxation after cooling was about six times normal, in the upper arm muscles only two times normal. As an additional parameter the mechanical resistance to passive stretching of a muscle has been studied. This passive muscular tension increased simultaneously with the onset of weakness. 4. The close relation between weakness and stiffness suggest that both symptoms are caused by the same basic defect which is probably located in the sarcolemma. It is suggested that a defect of the sodium channel causes a cooling-dependent increase in sodium conductance. Raised intracellular sodium causes in the first place membrane depolarization, and in the second place depression of calcium reuptake through competition by sodium for calcium binding sites. This would explain muscle stiffness and delayed relaxation as well.
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PMID:Influence of temperature on isometric contraction and passive muscular tension in paramyotonia congenita (Eulenburg). 9 68

The effect of ruthenium red, 2.5 to 5 muM, on ganglionic transmission in rat superior cervical ganglia and frog abdominal ganglia were studied in vitro. In rat ganglia, ruthenium red caused a spontaneous firing of ganglia cells, and an increase in the amplitude and duration of the compound action potential following a single stimulus volley. However, transmission following a conditioning volley or a repetitive stimulus train to the preganglionic nerve was depressed up to 60 sec. The asynchronous firing caused by bethanechol was potentiated by ruthenium red. In the frog, ruthenium red caused repetitive firing of ganglion neurons following either orthodromic or antidromic stimulation. It is suggested that the potentiation of the single potential and the spontaneous firing are due to a ruthenium red-induced increase in intracellular calcium concentration. The depression of transmission may be due to a temporary depletion of readily releasable acetylcholine. It is also suggested that ruthenium red has an effect on the postsynaptic membrane.
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PMID:Potentiation and inhibition of ganglionic transmission by ruthenium red. 9 31

We have investigated the effects of quinidine on the force of contraction and the intracellularly recorded action potential in papillary muscles isolated from human hearts. All preparations were obtained from patients undergoing corrective open heart surgery. The following results were obtained: (1) quinidine had a depressant effect on myocardial contractile force; (2) quinidine reduced the maximal upstroke velocity of the action potential; (3) quinidine shortened the plateau phase and prolonged the terminal repolarization of the action potential; (4) at higher concentrations quinidine reduced the resting potential; and (5) the depression by quinidine of both the plateau and the force of contraction was antagonized by isoprenaline. It is concluded that quinidine reduces the membrane conductances for sodium, calcium, and potassium ions. All of these actions of quinidine may contribute to the antiarrhythmic effects of the drug. The negative inotropic effect of quinidine can be explained by a depression of the calcium conductance at the myocardial cell membrane. The results show that earlier findings in laboratory animals regarding the effects of quinidine on the upstroke velocity and repolarization phase of the action potential are applicable to the human heart.
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PMID:Electrophysiological study of human ventricular heart muscle treated with quinidine: interaction with isoprenaline. 9 19

Intracoronary administration of contrast materials causes myocardial depression which is related to serveral physiochemical properties of the contrast solution. The role of variations in ambient calcium ions (Ca++) in mediating this effect was evaluated in 19 anesthetized dogs. Sodium meglumine diatrizoate caused decreases in left ventricular peak systolic pressure (LVPSP),-12.6 +/- 3.2%, and dp/dt at a left ventricular pressure (LVP) of 40 mm Hg, -14.3 +/- 4.1%. The total calcium (Cat) decreased from 10.2 +/- 0.2 to 6.5 +/- 0.2 mg%, while Ca++ decreased from 4.6 +/- 0.1 mg% to 2.3 +/- 0.7 mg%. In the presence of systemic hypocalcemia the myocardial depressant actions of this contrast materials were accentuated. Intracoronary administration of contrast material with added Ca++, calcium sodium meglumine metrizoate, caused no myocardial depression. Total calcium decreased only slightly (10.2 +/- 0.2 to 9.1 +/- 0.2 mg%), while Ca++ increased (4.8 +/- 0.1 to 5.1 +/- 0.2 mg%. During systemic hypocalcemia, the calcium metrizoate compound induced increases in LVPSP and dp/dt/LBP40. Thus, contrast materials caused myocardial depression which, at least in part, was related to reduction of ambient calcium through a dilutional and binding action. The addition of Ca++ to monomeric contrast materials reversed the myocardial depressant action and produced a transient rise in ambient Ca++.
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PMID:Alterations in calcium levels of coronary sinus blood during coronary arteriography in the dog. 9 41

Pancreatic islets were microdissected from ob/ob mice, loaded for 2 h with 45Ca and perfused with calcium-deficient medium. Irrespective of the glucose and calcium concentrations in the loading medium, increased glucose in the perfusion medium resulted in reduced amounts of radioactivity in the perfusate. A glucose inhibition of 45Ca washout was also evident when the specific radioactivity of the islets approached that of the labeling medium, indicating that the effect was not simply due to isotopic dilution. The depression of 45Ca washout diminished after culture of the islets in a serum-free medium and it was absent in islets taken from mice homozygous for the gene diabetes. The glucose effect became less pronounced when 50 micron D-600, an inhibitor of the calcium inward transport, was added to the calcium-deficient perfusion medium and abolished in the presence of 20 mM Ca-EGTA. The inhibition of the 45Ca washout observed is not necessarily due to a direct glucose interaction with the outward calcium transport but may also result from stimulation of the uptake and intracellular trapping of the cation.
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PMID:Glucose inhibition of 45Ca efflux from pancreatic islets. 9 51

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


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