NADH-cytochrome c reductase activity of liver cell membrane fraction was remarkably elevated after CCl4 administration and reached a peak in 6hr in female and 12hr in male rats, when separation of cell membrane was not disturbed. In female rats, microsomal and mitochondrial enzyme activities were not significantly influenced 6hr after CCl4 administration. The isolation procedure was adequate in separating membrane from microsome or mitochondria 6hr after CCl4 administration in female rats. Elevation of this enzyme activity in cell membrane is considered to be due to specific changes in cell membrane rather than to contamination of mitochondrial or microsomal particles in the course of separation.
Rate of contamination of mitochondria or microsome in plasma membrane fraction was studied by using marker enzymes such as cytochrome c oxidase, succinatecytochrome c reductase, glucose-6-phosphatase, etc.. Results are as follows. Succinate-cytochrome c reductase and cytochrome c oxidase activities in plasma membrane fraction from normal or CCl4-treated rat liver were less than 4% of those in mitochondria. In membrane, there was no significant increase in glucose-6-phosphatase and RNA located in microsome. From these results, it appears that increase of NADH-cytochrome c reductase activity in membrane following CCl4 administration dose not result from contamination of subcellular particles during isolation of membrane.
Morphological changes of liver cell membranes following CCl4 administration were electronmicroscopically studied by using negative staining method. Elementary particles were observed to be attached to the surface of cell membranes from normal rat liver and hexagonal subunit patterns were confirmed in the membranes after treatment of 1% deoxycholate. CCl4 administration caused the following changes; 1) Decrease in in numbers of elementary particles. 2) Progressive disappearance of hexagonal patterns from 6 to 72hr after CCl4 administration.
1) NADH-cytochrome c reductase activity in membrane was inhibited by p-chlo romercuric benzoate and N-ethylmaleimide, but not by KCN, NaN3, Antimycin A or rotenone. 2) Both NADH-cytochrome c reductase and NADH-ferricyanide dehydrogenase located in the membrane and microsome showed the same Km value respectively. These Km values were retained unchanged even in case of CCl4 treatment in vivo. 3) Membrane also contained cytochrome b5 and P-450, of which contents were much lower than those in microsome. CCl4, however, resulted in an increase of these heme proteins to twice in membrane, but a decrease to half in microsome. 4) NADH-cytochrome b5 reductase activity was only one third of NADH-cytochrome c reductase activity in membrane irrespective of CCl4 administration in vivo. 5) It is proposed that NADH-cytochrome c reductase in membrane orignates from microsome, but not from mitochondria, and that increase of enzyme activity after CCl4 administration may be caused by migration of heme- and flavo-proteins from endoplasmic reticulum to plasma membranes of liver cells in vivo.
Castration itself did not affect NADH-cytochrome c reductase and NADH-ferricyanide dehydrogenase activities of membranes in male or female rats. Time required for elevation of these enzyme activities evoked by CCl4, administration, in orchiectomized rats, was however apparently shortened to that in non-treated females'. Then, replenishment with 17-α-methyltestosterone completely recovered to the level in male control. In female rats, ovariectomy or replenishment with diethylstilbestrol produced no effects. Thus, male sex hormones seem to depress the elevation of these enzyme activities in the membranes following CCl4 administration.
In normal microsome, both NADH-ferricyanide dehydrogenase and NADH-cytochrome c reductase were almost completely solubilized by 0.5% DOC treatment, solubilization patterns of these enzymes being little affected by CCl4 injected treatment. On the other hand, in membranes, solubilizations of dehydrogenase and reductase were less than those in microsomes. Moreover, CCl4 administration lowered the solubility of the dehydrogenase in membranes and increased 3-fold the rate of reductase/dehydrogenase remaining in non-solubilized fractions. Reductase in membranes from CCl4-treated rat liver was found to be more resistant to solubilization by DOC.
Oxidized cytochrome c bound to membranes more easily than to microsomes. This binding was dependent on the ionic strength of the buffer solution, namely, the higher the concentration of buffer, the less the binding of cytochrome c to both fractions. Conversely, the bound cytochrome c was eluted more easily from microsomes than from membranes, the elution pattern also being dependent on buffer concentration.
Experiments were done on calculation results of ED50 of Aspirin and AP-14, as well as the potentiation between Aspirin and AP-14. Results are as follows: 1. ED50 of AP-14 by writhing method in mice was 32.52mg/kg. ED50 of AP-14 by pressure stimuli on mouse tail was 7.45mg/kg. 2. ED50 of Aspirin by writhing method in mice was 154.4mg/kg. ED50 of Aspirin by pressure stimuli on mouse tail was 31.62kg/kg. 3. When 1/2ED50 of AP-14 and Aspirin were administrated at the same time, analgesic effect increasec more than ED50 of AP-14 or Aspirin both by writhing method and pressure stimuli on mouse tail.
The present study was undertaken to determine whether or not MAO activity and serotonin level in brain improves effect by adaptation hormones of homeotasis injured by formalin or reserpine injections. Male Wistar rats were subcutaneously injected with 5% formalin (8mg/kg) or 0.1% reserpine (1.25mg/kg) and or 0.2% ACTH (5mg/kg) or 2.5% cortisone (20mg/kg) every two days for 30 days. They were fed a high sucrose diet and 5% sucrose solution during this period. Animals were killed 16hr after last injections and MAO activity and serotonin content of whole brain were measured. Results are as follows. 1) Formalin, ACTH or cortisone induced hyperactivity of MAO, although each hormone combined with formalin induced no such activation. 2) There were no significant differences in the serotonin levels from brains after either treatment. 3) Reserpine induced hyperactivity of MAO and. such activation was furthermore provoked in the combination with cortisone but inhibited with ACTH. 4) Depletion of serotonin by reserpine was inhibited in combination with ACTH but not with cortisone. 5) Reserpine combined with formalin induced hypoactivity of MAO, however such combination did not influence the depletion of serotonin by reserpine.
Comparative studies were made on spinal neuronal activity among: Chlorpromazine, Levomepromazine, Prochlorperazine, Perphenazine, Haloperidol, Thiothixene, Diazepam, Hydroxyzine, Imipramine, Harmine and γ-aminobutylic acid (GABA). All these drugs showed an inhibition tendency of the action potential in spinal neuronal activity. Individually, there were variations concerning quantity, quality and time. As many more psychotropic will be utilized in the future there will be an increasing need for drug evaluation of which these findings will be significant.
1-tert-Butylamino-3-[o-(tetrahydrofurfuryloxy)phenoxy]-2-propanol hydrochloride (Y-6124) inhibited at each dose of 50, 100 or 500μg/kg administered intravenously arrhythmia induced by rapid intravenous injection of 10μg/kg epinephrine in dogs anesthetized with sodium secobarbital, or arrhythmia induced by continuous infusion of 5μg/kg/ min epinephrine into the vein of a dog anesthetized with fluothane. Y-6124 and propranolol inhibited these epinephrine-induced arrhythmias at the almost the same dose as that of its β-blocking action. Y-6124 inhibited arrhythmia induced by continuous intravenous infusion of 5μg/kg/min ouabain in anesthetized dogs at a dose of 2.5 or 5mg/kg i. v., but did not change the lethal dose of ouabain in dogs. Propranolol inhibited arrhythmia and increased the lethal dose of ouabain in dogs. Y-6124 had a therapeutic effect on arrhythmia induced by intermittent and cumulative administration of ouabain at a dose of 2.5mg/kg i. v. or more. Potency was almost the same as that of propranolol.