The effects of various drugs on fibrillation in chronically denervated skeletal muscles of rats were studied by Brown (1937) (1) and Solandt and Magladery (1940) (2), and they reported that the fibrillation may be prevented by the administration of quinidine and acetylcholine (ACh) but not by that of ether, sodium barbitone, atropine, eserine and curare. Furthermore, McIntyre, King and Dunn (1945) (3) and Jarcho, Berman, Eyzaguirre and Lilienthal (1951) (4) reported that ACh, decamethonium and d-tubocurarine aroused an almost immediate outburst of electrical fibrillary activity, rapidly followed by complete silence in denervated mammalian muscles and the effect of ACh on the denervated muscle may be inhibited by the previous injection of sufficient doses of d-tubocurarine.
It is said that fibrillation is a physiological response of skeletal muscle to denervation and is accompanied by action potentials referred to as fibrillation voltages. Denny-Brown and Pennybacker (1938) (5) found that chronically denervated skeletal muscle undergoes certain degenerative changes and produces the action potentials spontaneously. Golseth and Fizzell (1947) (6) investigated in detail the fibrillation action potentials, which may be either monophasic or diphasic in character, and found them to be 2 to 30 c/s in frequency, 10 to 100 μV in potential and 1 to 2 msec in duration. Cannon and Rosenblueth (1949) (7) pointed out that the chronically denervated skeletal muscle becomes much more sensitive to ACh than the normal muscle. Moreover, ThesleE (1960) (8) reported that the whole surface of denervated muscle fiber is as sensitive to ACh as the end-plate region which has maintained its responsiveness to it. The mechanism of the development of the fibrillation voltages has not been sufficiently clarified yet, although Woodbury and Ruch (1960) (9) explained that the circulating ACh is the probable cause of the fibrillation voltages. In our laboratory, the effects of various drugs including nicotine and l-1, 2-diphenyl-l-ditmethylaminoethane (Spa) on the fibrillation voltages were studied to get a clue toward solution of the following problems: whether or not the circulating ACh is the stimulating substance producing the spontaneous action potentials in the chronically denervated skeletal muscle, and whether or not Spa acts directly on the skeletal muscle membrane.

抄録全体を表示

There are many studies on the action of drugs on the central nervous system by means of EEG recording. But little has been made using EEG of an embryo. If drugs are applied to an embryo in which the nerve cells are still in process of maturation in the central nervous system, the changes caused in EEG may provide useful clues for elucidating the mode of action of the drugs. The present study was conducted following this idea. The development of the spontaneous electrical activity in the brain of chick embryos were studied in detail, and then the effects of several drugs were examined.

抄録全体を表示

In the previous paper, the remarkable difference in strychnine toxicity between adult female and adult male rats was reported (1).
This sex difference is observed in cases of intraperitoneal, subcutaneous or oral administration of the drug but not by intravenous injection. After pretreatment with SKF 525 A such sex difference also disappeared.
The different capacities of breakdown of strychnine by liver of female and male rats were supposed to account for such sex difference. It is worth while for noticing that such remarkable sex difference in strychnine toxicity after intraperitoneal injection of the drugs takes place within 10 minutes.
It has been generally considered that such short time is not enough to produce marked difference through metabolic processes, and a different sensitivity of central nervous system in both sexes was considered to be a responsible factor (2, 3).
In recent time, the authors have demonstrated that there is a marked decrease of strychnine toxicity through an increase of strychnine metabolism by pretreatment (48 hours before) with phenobarbital, phenaglycodol, thiopental and glutethimide (4-6).
These results suggested a rapid “in vivo” metabolism of strychnine which could produce a marked difference in the toxicity by a modification of metabolic rate.
In this paper, the possibility of the presence of such sex difference in metabolism of strychnine between both sexes of rats was studied.

抄録全体を表示

The depletion of catecholamine in the brain, heart, adrenal medulla and other sympathetically innervated tissues by acutely administered-reserpine has been demonstrated by Hillarp (1), Holzbauer and Vogt (2), Kroneberg and Schumann (3) and Mirkin (4). The depletion of the level of the amine in the adrenal medulla during insulin hypoglycemia in cat (5) and rat (6, 7), by administration of eserine in rat (8) and by repeated administration of acetylcholine in cat (9, 10) was already confirmed. Similar depletion of the amine in the adrenal medulla of eviscerated cat by stimulation of splanchnic nerve was shown by West (11) and Holland and Schumann (12). The loss of the amine from the adrenal medulla by a single dose of reserpine has been attributable mainly to stimulation in the central nervous system which was conducted to the organ by way of the splanchnic nerve ; because spinal section at T₂ (13) or severance of splanchnic nerve (3) markedly diminished the effect in rat and cat.
Vogt (14), Vogt and Holzbauer (2, 15) studied the effects of some drugs including central stimulants on the content of catecholamine in the hypothalamus, and in the innervated and denervated adrenal gland of cat and dog. Among the drugs tested, insulin, morphine and beta-tetrahydronaphthylamine proved to deplete effectively the amine in the hypothalamus and in the innervated adrenal gland. There was also an excellent correlation between the loss of hypothalamic amine and the stimulation of sympathetic center resulting in a loss of the amine in the innervated adrenal gland. In this laboratory Shimamoto and Torii (16) studied the effects of intravenous and intracarotid injections of reserpine on the hypothalamic pressor response and on behavior in rabbit. They obtained the evidence that though the intravenous injection of reserpine revealed a marked depression of the hypothalamic pressor response and a usual sedation, the intracarotid injection did not reveal any effect. In relation to their results, this series of experiments was attempted to study the effects of intravenous and intracarotid injections of reserpine on the content of catecholamine in the brain, heart and adrenal gland of rabbits.

抄録全体を表示

In the previous paper (1) it has been reported that the intracarotid injection of 0.1 mg/kg of reserpine in rabbit increased the content of noradrenaline in the whole brain and brain stem at 30 minutes, and also in the brain stem at one hour after the administration, while the content of noradrenaline in the atria and of adrenaline in the adrenal gland did not change, or decreased below 10% of the normal content. But, thereafter, the content of noradrenaline in brain tissues and the atria, and of adrenaline in the adrenal gland decreased steeply and the peak effect was attained at the third hour of the administration. The animal behaved normally or sometimes showed a slight sign of motor excitement (2). The intravenous injection of 0.1 or 1.0 mg/kg of reserpine decreased the content of central and peripheral noradrenaline and adrenaline. The decrease of the peripheral noradrenaline or adrenaline caused by the intracarotid injection of 1.0 mg/kg of reserpine was usually more marked than the decrease of the amine caused by the intravenous injection of same dose of reserpine. From the results, Higuchi (1) suggested that the depletion of catecholamine in the peripheral organs by, reserpine was derived from two mechanisms: the biochemical effect and the central effect. The central effect of reserpine to decrease the content of noradrenaline or adrenaline in the peripheral organs might be caused by the decrease of noradrenaline in the sympathetic center` located in the brain stem.
Shimamoto and Torii (2) showed that the previous treatment of rabbit with cocaine or methamphetamine reversed the reserpine sedation at an early period of reserpine administration, but, later potentiated the reserpine sedation. Kikuchi (3) obtained the similar effect of the pretreatment of cocaine or methamphetamine on the action of reserpine in the rabbit from the elect roe ncephalographic studies.
In the present report, the effect of pretreatment of rabbit with methamphetamine or cocaine on the catecholamine depleting action of reserpine was studied.

抄録全体を表示

Recently Axelrod et al. have found that metanephrine and normetanephrine are principal metabolites of epinephrine and norepinephrine (1, 2). Wylie et al. showed that the catechol-O-methyltransferase was very strongly and competitively inhibited by pyrogallol (3-6). On the other hand it has been reported by many researchers that catecholamines are also attacked by monoamine oxidase. The purpose of the present experiments was to study the relationship between activities of these enzymes and changes of the level of endogenous catecholamines. It was of interest to know whether there were any changes in endogenous catecholamine metabolism, and whether the activities of O-methyltransferase and monoamine oxidase altered, after the continuous daily administration of an O-methyltra n sfe rase inhibitor, since these enzymes are related to the regulation of endogenous catecholamine metabolism.

抄録全体を表示

The depletion of serotonin and catecholamine from the tissues by reserpine in vivo and in vitro has been confirmed by many authors. The release of catecholamine from the hearts of various mammals in vivo by reserpine was already shown by Bertler et al. (1), Paasonen and Krayer (2), Waud et al. (3). Carlsson et al. (4), reported that the intravenous administration of 5 to 10 μg/kg of reserpine in rabbit decreased the content of heart catecholamine (noradrenaline) significantly, while the same procedure did not affect the content of brain catecholamine. The .sim.ilar results were also obtained by Orlans et al. (5). Higuchi et al. (6, 7) in this laboratory showed that the depletion of catecholamine in the heart of rabbit which had been injected 0.1 to 1.0 mg/kg of reserpine 24 hours before, was about 90% of the normal content.
Tachi (8) in this laboratory has found that the administration of 10^-6 of reserpine to the atrial preparation of rabbit revealed negative chronotropic and inotropic actions, and that the same procedure of above 10^-5 of reserpine abolished the rhythmic contraction of the preparation within 60 to 120 minutes after the administration of the drug. Toda (9) in this laboratory has studied the effects of reserpine on the transmembrane potential of the pacemaker and non-pacemaker fibers of the extirpated rabbit's atrium, and also showed that reserpine in the concentration of above 10^-5 depressed the potential and at last abolished it. Further, they (Tachi, Toda) have showed that although the replacement of reserpine-Ringer solution in the organ bath with normal Ringer solution did not restart the rhythmic contraction of the auricle and the rhythmic changes of the pacemaker and non-pacemaker potentials, both rhythmic patterns of the atria recovered in response to definite doses of adrenaline or noradrenaline. From the results it is suggested that the catecholamine which is subjected to release by reserpine might have a determining role in the initiation and maintenance of rhythmic contraction of the heart.
Pepeu et al. (10) studied the effect of reserpine on the catecholamine content in the extirpated guinea pig's heart, suspended in Tyrode-bicarbonate solution, and found some decrease of catecholamine at 6 hours after the administration of 10^-5 of reserpine.
In the present experiment the effects of reserpine, iproniazid, and SKF 385 have been studied. It has been expected that the depressive effect of reserpine on the rhythmic contraction of the preparation might have some correlation with the depletion of the catecholamine,

抄録全体を表示

It is one of the most fundamental problems not only in the enzymological but also in the pharmacological researches to consider quantum-chemically the interaction between an enzyme and its inhibitor on the molecular basis.
The author has recently extensively studied on the relation between electronic structure of phenylacetate derivatives and their rates to be hydrolyzed by the cholinesterase (1); though this paper deals partially with those results, it is confined at present to the problem on the relationship between the electronic structure and inhibiting force of cholinesterase inhibitors.
A competitive inhibition seems to be of a simpler reaction type and such a secondary effect as the molecular deformation to be derived from the drug absorption may be also easily excluded, so it would be the most favorable object for the present experimentation.
Wilson et al. (2) showed the development of competitive inhibition between cholinesterase and various phenyltrimethylammonium derivatives assuming it as derived from the hydrogen-bonding of the esteratic site of cholinesterase to phenylhydroxyl group of those derivatives, and they also emphasized that in order to determine the inhibiting force in those reaction systems the spacial arrangement of molecules or molecular complimentariness was more important factor than the chemical change thereby exerted. They added, however, that the significance of chemical change as a cause of the inhibiting force could not be entirely avoided, and they attributed the weakness in the inhibiting force of 2-hydroxybenzyl.trime thylammoniurn bromide (compound No. 8 in Table 1) to the larger value of pKa than that of 3 hydroxypheny.ltrimethylammonium salts, all of which, however, were the same in spacial distance from the quaternary ammonium radical to the hydroxyl group and from the esteratic site to the anionic site of cholinesterase. But if it might be true, there is a discrepancy for the fact that the pKa value of the compound No. 8 is 8.7 which is weaker in the inhibiting force than the compound No. 5, that is 6-methoxy-3-hydroxyphenyltriniethylammonium chloride, the pKa value (8.6) of the latter being, however, almost as large as that of the compound No. 8. Thus, it is clear that there is at least no intimate connection between the pKa value and inhibiting force in the case of 3-hydroxyphenylmethylammonium derivatives.
According to Wilson et al. (2) the fact that 2.9 kcal of free energy change resulted from the K_I ratio of the compound No. 1 vs. the compound No. 6 was just coincided to what was brought about by the hydrogen-bonding in this reaction appeared to give some support to their hydrogen-bonding hypothesis. But neither this energy change would necessarily brought about by the hydrogen-bonding nor this phenomenon would be characteristic of the hydrogen-bonding. In the author's opinion there should be three possibilities to be taken into consideration in order to interpret this phenomenon quantum-chemically which are as follows :
(i) There would be the formation of charge transfer complex or some substitution reaction, instead of the hydrogen-bonding.
(ii) There would be surely the hydrogen-bonding, the pKa value being, however, no appropriate decisive index.
(iii) Apart from the hydrogen-bonding, there would be some other forces, e.g., van der Waals', contributable to the reaction.

抄録全体を表示

Within these several years, owing much to tracer experiments (1, 2), circulating metabolic pattern of catecholainine (CA), epinephrine (E) and norepinephrine (NE), has been clarified nearly completely. Most part of circulating CA undergoes O-methylation to yield metanephrine (MA) and normetanephrine (NMA) (3, 4), and a part of these is excreted in the urine in conjugated form but the rest part is further metabolized by monoamine oxidase (MAO) to give vanillylmandelic acid (VMA) (5), a stable final common metabolite of both E and NE, and without further metabolism and conjugate formation VMA is excreted in the urine. A lessor portion of circulating CA first undergoes deamination to make 3, 4-dihydroxymandelic acid (DOMA) and a part of which is excreted in free form and the rest is O-methylated to give VMA which is excreted in the urine.
Since, according to Goodall and Kirshner (1, 2), infusion of dl-2-C¹⁴-E and dl-2-C¹⁴-NE makes the recovery of as much as 27 and 32%, respectively, of the infused radioactivity as VMA, determination of this compound together with VMA from endogenous metabolism is expected to afford a reasonable index of CA level in the organism. As for determination method for urinary VMA, there have been reported several representative ones besides vanilline (V) colorimetric method by Sandler et al. (6, 7). Two dimension paper chromatographical method by Armstrong et al. (8), high voltage paper electrophoresis by Studnitz et al. (9) and some others require difficult technique or elaborate apparatus. The authors improved Sandler's method and worked out a new method which can be employed in routine clinical examination with high specificity and reliability.
Determination of urinary DOMA, however, has never been tried on the ground that this compound is less stable than VMA and regarded to be excreted far small amount as an intermediate metabolite of both E and NE. But determination of DOMA, like that of VMA, MA or NMA, is considered to give an index of the overall CA level in the organism and is still expected to make a better reflect of metabolic magnitude of endogenous CA than determination of VMA if there was a comparatively large route for endogenous CA metabolism to give DOMA, as reported by Crout (10) and supported by Johnson (11). In this respect the authors elaborated a determination method for urinary DOMA based on an entirely new idea on conversion of DOMA to protocatechu aldehyde (PA).

抄録全体を表示

It has been shown in the previous report (1) that reserpine depressed the transmembrane potentials of the sinoatrial pacemaker and non-pacemaker atrial fibers of the isolated rabbit's atrium in rhythm and in configuration. Within 2 hours after the application of reserpine above the concentration of 10^-5 the action potentials disappeared totally. Adrenaline or noradrenaline antagonized the depressive effect of reserpine on the action potential, and the administration of either amine restarted the rhythmic action potentials. The mode of action of reserpine on the action potential was discussed being derived from release and depletion of noradrenaline in the atrial fibers.
The content of noradrenaline in the spontaneously beating atrium of guinea-pig which had been immersed in oxygenated Tyrode's solution at 29°C decreased gradually (2). Using the isolated atrium of rabbit, Matsuo (3) showed that the concentration of 10^-5 of reserpine resulted in the depletion of about 30 to 40% of the amine at 2 hours after the administration in contrast to the slight decrease (5 to 10%) of control amine content. On the other hand, despite of deprivation of about 90% of noradrenaline in the heart of various animals in response to 0.1 to 1.0 mg/kg of reserpine administered intravenously (4-8), the heart continued its rhythmic contraction in situ. This difference of action of reserpine on the heart between in vivo and in vitro suggests some mechanisms of action of reserpine other than the liberation of noradrenaline from the heart in vitro or some compensatory mechanisms of heart in situ to maintain the rhythmic contraction against the extreme depletion of noradrenaline.
Plummer et al. (9) and Krayer et al. (10) showed that reserpine increased the heart rate in the heart-lung preparation of dog. The latter authors postulated that the increase of the heart rate at the early phase of reserpine action was attributable to the increased liberation of noradrenaline into the perfusion fluid from the heart. However, the atrial preparation of rabbit showed only a decrease of rate of the action potential or the rhythmic contraction in response to a wide range of reserpine concentration (1, 11). The depression of the atrial rate might be caused by the non-specific antiaccelerator effect of reserpine, originally described by Krayer and Fuentes (10). Pepeu et al. (2) showed that the pretreatment of the atrium of guinea-pig with iproniazid reversed the noradrenaline depleting action of reserpine in vitro, but the similar treatment with phenylisopropyl hydrazine did not reverse the reserpine effect. Tachi (personal communication) and the author showed that the pretreatment of rabbit with iproniazid or SKF-385 (2-phenylcyclopropylamine) did not antagonize the depressive effect of reserpine on the atrium in vitro, though the pretreatment of these monoamine oxidase inhibitors slightly but significantly prolonged the course of the reserpine action. Assaying the content of noradrenaline in these atria, Matsuo (3) confirmed the reversal of reserpine action by iproniazid and SKF-385.
In this experiment the effects of reserpine were investigated on the transmembrane potentials of atrium of rabbit pretreated with reserpine or SKF-385 and those of the normal atrium which was electrically driven after the excision of its sinoatrial node.

抄録全体を表示