A method for the quantitative determination of luteoskyrin in mouse liver is described. Luteoskyrin was extracted with ether from the liver homogenate after acidification with HCl, purified by thin-layer chromatography and determined by spectrophotometry. Five μg of luteoskyrin added to the liver homogenate which was equivalent to one gram tissue was determined with a recovery rate of 97% and 1 μg, under the same conditions, with a recovery rate of 70%. Luteoskyrin in the amount of 0.5 μg could be detected on the chromatogram, but could not be determined quantitatively. A radioactivity corresponding to 0.92μg/g tissue of ³H-luteoskyrin in the livers from the mice injected intravenously with this compound was extracted into ether with a recovery rate of 93% and separated on the thin-layer chromatogram with a recovery rate of 81%. The lower limit of quantitative determination of luteoskyrin in one gram of liver was 1 μg. Amounts of luteoskyrin in the livers of mice poisoned with this mycotoxin were estimated. Luteoskyrin was recovered in a large quantity in livers from male mice while detection in the liver of females was nil.

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The effects of 5-hydroxytryptamine and morphine on the stomach motility were determined in in situ experiments. 5-Hydroxytryptamine and morphine inhibited stomach motility of unanaesthetized cats but did produce a slight contraction of the stomach of anaesthetized cats. In unanaesthetized rabbits, 5-hydroxytryptamine caused a contraction, followed by an inhibition of motility, and morphine depressed motility. The 5-hydroxytryptamine-induced contraction is a direct action on smooth muscle and the inhibition of spontaneous movement due to 5-hydroxytryptamine may be, in part, mediated through catecholamine-release and in part, result from paralysis of the receptors for 5-hydroxytryptamine in the cholinergic nerves in the stomach. In anaesthetized rabbits, 5-hydroxytryptamine produced contraction and morphine had no effect. In unanaesthetized guinea pigs, 5-hydroxytryptamine caused a contraction and morphine abolished spontaneous movement of the stomach. In anaestetized guinea-pigs, 5-hydroxytryptamine caused contraction and morphine produced no effect. The 5-hydroxytryptamine-induced contraction of the guinea pig stomach is indirect. From these results it is concluded that the differences in the modes of actions of 5-hydroxytryptamine and morphine on gastric motility are related to differences in species and experimental conditions such as anaesthesia.

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The local anesthetic activities of cis- and trans- dl-1-benzoyloxy-2-dimethyl-amino-1, 2, 3, 4-tetrahydronaphthalene were compared using several methods with guinea-pigs. The cis compound (YAU-17) was 2.9 to 6 times as potent as its trans isomer and exceeded procaine, lidocaine and cocaine in potencies of corneal anesthesia, intracutaneous anesthesia and sciatic nerve block. In another experiment on isolated frog sartorius muscle, all of the local anesthetics suppressed the twitch contractions elicited by stimulation of the sciatic nerve. The neuromuscular blocking activity of the cis compound was more pronounced than that of the trans form. Supersensitivity to noradrenaline was produced by both of the stereoisomers in isolated was deferens of guinea-pigs although there was no difference in the activity. The sensitizing action was also demonstrable with cocaine and lidocaine but not with procaine. When injected intravenously into mice, the cis compound was twice as toxic as its isomer. It is postulated that stereoselectivity is to some extent involved in the mechanisms of action of the local anesthetic agents.

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The effects of ammonium sulfate on mitochondrial monoamine oxidase (MAO) in beef liver were studied. The initial stage of the reaction was measured with an oxygen electrode and the long term reaction was measured manometrically. With tyramine or benzylamine as substrate, addition of ammonium sulfate increased the initial reaction but decreased the long term reaction. Ammonium sulfate had similar effects on solubilized MAO. Inhibition of MAO activity in both the initial and long term reaction by excess substrate was diminished by addition of ammonium sulfate. The effects of ammonium sulfate on MAO were reversible. Salts having an -SO₄ group, such as Na₂SO₄ and K₂SO₄, increased MAO activity in the initial reaction while salts having an -NH₄ group, such as NH₄Cl and NH₄NO₃, inhibited it. However, all these salts inhibited MAO activity in the long term reaction. The mechanism of activation of MAO activity by addition of ammonium sulfate is discussed.

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Effects of monovalent cations on Ca-efflux were examined in rat brain cortex slices, synaptosomes and synaptic plasma membranes. Effluxes of ⁴⁵Ca from brain slices and synaptosomes were stimulated by Na⁺ in medium and the effects of Na⁺ on the ⁴⁵Ca-effluxes disappeared at low temperature. Furthermore, we observed that Rb⁺ had more effect than Na⁺ on ⁴⁵Ca-efflux from the synaptosomes, while Li⁺ had less effect. On the other hand, release of ⁴⁵Ca from the synaptic plasma membranes which had been preincubated with ATP, Mg⁺⁺ and ⁴⁵Ca was stimulated by Na⁺ and Li⁺. But Cs⁺ and Rb⁺ were less effective on the release. These results indicate occurrence of Na-dependent Ca-efflux at nerve endings. However, the assumption that ATP-dependent Ca-binding with synaptic plasma membranes may be a partial reaction of Ca-efflux was not supported by these experiments.

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The effects of La⁺⁺⁺, Mn⁺⁺ and ruthenium red (R.R.) on Ca-uptake of synaptic plasma membranes (S.P.M.) were investigated. La⁺⁺⁺ (0.1 mM), Mn⁺⁺ (0.2 mM) and R.R. (0.1 mM) selectively inhibited Mg·Ca-ATPase but did not significantly affect Mg-ATPase activity. The apparent Ki values of La⁺⁺⁺, Mn⁺⁺ and R.R. for Mg·Ca-ATPase were 0.05, 0.06 and 0.03 mM, respectively. La⁺⁺⁺, Mn⁺⁺ and R.R. did not affect Ca-uptake at concentrations which strongly inhibited Mg·Ca-ATPase activity. These results indicate that Ca-uptake by S.P.M. differs from that by sarcoplasmic reticulum.

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The cardiovascular effects resulting from intracisternal (i.c.) injections of sympathomimetic amines were studied in α-chloralose-urethanized rats. Norepinephrine (0.5-5 μg i.c.) caused a typical rise in blood pressure with no significant change in heart rate and a fall in blood pressure with a bradycardia, which were completely blocked after treatment with phentolamine (10-50 μg i.c.). L-isoproterenol (0.05-0.5μg i.c.) and trimetoquinol (0.5-3 μg i.c.), a β-sympathomimetic agent, usually caused a fall in blood pressure with a tachycardia, which was reduced after treatment with propranolol (10-50 μg i.c.), but trimetoquinol was inclined to cause a rise in blood pressure with a tachycardia. Epinephrine (5 μg i.c.) showed both centrally mediated α- and β-sympathomimetic effects. Tyramine (0.5-1 mg i.c.) caused mixed blood pressure responses presumably due to a release of norepinephrine and epinephrine, and these responses were partially blocked after treatment with phentolamine (100 μg i.c.) or propranolol (50 μg i.c.). These observations suggest that both α- and β-sensitive adrenergic zones may exist on the vasomotor center of the pons and medulla in rats, and both norepinephrine and epinephrine might centrally play a physiological role as the neurotransmitters controlling blood pressure in rats.

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In helically-cut strips of canine cerebral arteries, the dose-response curve of serotonin was not influenced by 10^-7 M phentolamine but was slightly moved to the right and downward at 10^-6 M. The contractile response to serotonin was unaffected by cocaine (3×10^-6 M), atropine (10^-6 M) and propranolol (10^-6 M). The addition of lysergic acid diethylamide (LSD), ergotamine and methysergide caused a dose-dependent contraction. Treatment with LSD (10^-9 and 10^-8 M), ergotamine (10^-10 to 10^-8 M) and methysergide (10^-8 to 10^-6 M) shifted the dose-response curve of serotonin to the right and downward in a dose-dependent manner. The inhibitory effect of methysergide was reversed by washing, while that of ergotamine was not reversed. Apparent pA₂ values of LSD, ergotamine and methysergide were 9.17, 9.63 and 7.92, respectively. Contractile responses to 20 mM K⁺ were not significantly influenced by these blocking agents even in the highest concentrations used. It may be concluded that an alpha-adrenergic mechanism is not involved in the genesis of serotonin-induced contractions and that serotonin acts directly on serotonergic receptors in canine cerebral arteries.

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The tracheal smooth muscle dissected free from connective tissues was used as a test preparation, since isoprenaline caused a decrease in cyclic GMP in the muscle while it caused an increase in cyclic GMP in the remaining tracheal tissue. Acetylcholine, histamine and papaverine increased both cyclic AMP and cyclic GMP levels in the tracheal muscle. Isoprenaline increased the cyclic AMP level but decreased the cyclic GMP level. However, when tracheal muscle was incubated with isoprenaline in the presence of acetylcholine, isoprenaline did not cause a decrease in cyclic GMP but rather a significant increase in cyclic AMP after only 1 min incubation. These results indicate that the relaxation of the tracheal muscle by isoprenaline is initiated by the increase in cyclic AMP but is not associated with the change in cyclic GMP.

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Contractile responses to K, ACh, Ba and exogenous Ca of rectal strips from mice were recorded isotonically. These responses consisted of phasic contraction and subsequent tonic contraction. In Ca-depleted preparations exposed to Ca-free bath medium, the contractions by K and ACh disappeared but the contraction by Ba remained constant. This residual contraction by Ba is presumably due to a direct stimulation of Ba to contractile elements of muscle. Metabolic inhibitors (anoxia and DNP) abolished tonic contraction without affecting phasic contraction by exogenous Ca. In Ca-free bath medium, tonic contraction by exogenous Ca immediately disappeared whereas phasic contraction gradually decreased and about 3 hr later remained constant in parallel with the occurrence of residual contraction by Ba. After pretreatment with the removal of Na from bath medium, which produced Ca-release action, phasic contractions by exogenous Ca in Ca-free bath medium were depressed like those by K, ACh and Ba. These results suggest that the phasic contraction by exogenous Ca is produced mainly by release of Ca and partly by influx of Ca. Thus, it is suggested that the same mechanism of Ca-induced release of Ca from the storage sites as described in skeletal muscle is also operating in rectal smooth muscle of mice.

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Curves of experimentally plotted log (dose ratio-1) vs.-log [B] for the antagonism between adrenergic β-mimetics, isoproterenol (ISO) and trimetoquinol (TMQ), and various β-antagonists in relaxation of guinea-pig trachea could not be reasonably fitted to Schild's equation which has been commonly used in the analysis of drug-antagonism. Taking into consideration the saturable uptake process of the drug used herein, the equation presented in this paper fitted fairly well to the experimental curves and explains the following results : 1, TMQ was more strongly antagonized than ISO by all the blocking agents tested, that is, the apparent modes of antagonism were different between ISO and TMQ although they are considered to interact with the same receptor site. 2, The slope of the curve for a given antagonist markedly differed between ISO and TMQ. It is hypothesized that ISO is more easily taken up than TMQ. This was experimentally confirmed : i.e., ISO was potentiated about 8 fold by inhibiting the uptake process with dibenamine while TMQ was not. By pretreatment with dibenamine, the log (dose ratio-1) vs.-log [B] curve for the ISO-propranolol antagonism was shifted upward and superimposed with the theoretical curve of antagonism in which uptake of the agonist was neglected.

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In order to elucidate the biochemical anti-inflammatory properties of naproxen, the effects of this compound on activities of mucopolysaccharase [β-glucuronidase (β-Gase) and lysozyme (LZ)], acid protease (APase) and collagenolytic enzyme (CL) in inflamed tissues were investigated by means of a proliferative inflammatory model in filter-paper-implanted rats. In the preventive test, naproxen strongly inhibited granuloma formation and exudate accumulation as did indomethacin and prednisolone. Although the inhibitory effects of naproxen on all these enzymes were quite evident, indomethacin failed to inhibit APase activity. Prednisolone did not significantly inhibit LZ and APase activities in granuloma. In the curative test, prednisolone caused a marked decrease in the weight of the granuloma already formed and in the volume of the exudate, but with naproxen and indomethacin there was only a slight decrease. Naproxen and indomethacin induced slight but significant inhibition of LZ and CL activities, while prednisolone showing a weak inhibition of CL activity only. From these results, it may be concluded that anti-inflammatory and anti-rheumatic effects of naproxen are partly attributable to its inhibitory actions on these lysosomal enzymes.

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Responses of the isolated heart from the guinea pig treated chronically with digitoxin until the T wave had disappeared were studied. The development of the abnormal ECG pattern was abolished by a simultaneous injection of taurine and digitoxin. Taurine also inhibited the change by digitoxin of the responses to acetylcholine and ouabain but not to noradrenaline. The causal relationship between the inhibitory effect of taurine and prevention of the development of arrhythmias remains obscure.

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