巻号一覧
28 巻, 1 号
選択された号の論文の7件中1～7を表示しています
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上西 仁, 砂野 哲1978 年 28 巻 1 号 p. 1-16
発行日: 1978年
公開日: 2011/06/07
ジャーナル フリーElectrical and mechanical activities in high-K-induced contracture of guinea pig ureter and taenia coli were studied using the sucrose-gap method. Ureter immersed in high-K solution showed a contracture consisting of three components as well as twitch contractions evoked by a few spikes which were observed during the depolarizing phase. Reapplication of high-K solution after a short washing procedure with normal solution induced a contracture composed of only the first and the third components. No action potential was observed during the course of membrane depolarization by this procedure. High-K-induced contracture was highly sensitive to extracellular Ca: no tension development of the ureter despite the membrane depolarization was observed in Ca-free high-K solution. The addition of Ca to Ca-free high-K solution caused a contracture similar to that by high-K solution in the presence of Ca. Verapamil (10-5 M) blocked all three components, leaving only slightly depressed twitch contractions initiated by action potentials. The possibility that all of these components of high-K-induced contracture were initiated by influxed Ca from extracellular space was also strengthened.抄録全体を表示PDF形式でダウンロード (1529K) -
塚田 徳昌1978 年 28 巻 1 号 p. 17-31
発行日: 1978年
公開日: 2011/06/07
ジャーナル フリーThe effects of heart rate and l-isoproterenol on the functional refractory period (FRP) of the atrioventricular (AV) node were analyzed in anesthetized dog. A rectangular hyperbola was adopted to express the relationship between the AV conduction time of the premature beats and the atrial coupling intervals. FRP was shown to be expressed as FRP=E+2√a C-C/(T-E) . Thus, it is a function of the effective refractory period (E), basic cycle length (T), and C, a constant. A decrease in the basic cycle length caused a decrease in the effective refractory period as well as FRP; the minimum conduction time remained unchanged. As expected from the above equation, relationship of FRP to the basic cycle length was curvilinear. The above equation also indicates that changes in FRP produced by a change in the basic cycle length were to be ascribed to the change in the AV conduction time of the basic beats. Therefore, FRP under this condition cannot be equated with the refractory period in its true sense. In the paced hearts, l-isoproterenol hydrochloride caused a decrease in the effective refractory period, FRP, C and the minimum conduction time, and the changes in FRP were shown to be correlated with the changes in the effective refractory period, indicating that the change in FRP attained in a given fixed cycle length may be due to a change in the effective refractory period.抄録全体を表示PDF形式でダウンロード (1329K) -
林 治秀1978 年 28 巻 1 号 p. 33-45
発行日: 1978年
公開日: 2011/06/07
ジャーナル フリーThe permeabilities of the frog tongue epithelium for potassium and other ions during a short time span were investigated electrophysiologically.The fungiform papilla of the bullfrog tongue was suctioned into a U-shaped glass suction electrode, through which Ringer solution was circulated. Compound nerve action potentials were recorded antidromically from the electrode following electrical stimulation of the glossopharyngeal nerve. When more than 5-10 mM potassium salts, 30 mM RbCI, 30 mM CsCl, 0.025 g in dl solution tetrodotoxin, 0.1 g in dl solution lidocaine hydrochloride or 3 g in dl solution ethanol, each of which was dissolved in Ringer solution containing 1.9 mM KCl, were flowed through the suction electrode, only the negative components of action potentials were gradually reduced and finally disappeared. The time needed for 50 % reduction of negative components was about 10 sec for 0.1 M potassium salts and longer for the nonelectrolytes. A single suctioned papilla, which was flowed with various test solutions, was stimulated electrically and the change in current threshold of the papillary nerve was measured by recording orthodromic action potentials from the glossopharyngeal nerve. The threshold decreased within 10 sec after 0.05 M BaCl2 was flowed, but increased within 10 sec after 0.1 M KCl was flowed. The reduction of negative components of nerve action potentials may be due to the conduction block induced by potassium and other ions invading to the space around axon terminals. The threshold change also may be induced by the ions reaching the axon. These results suggest that chemical substances can rapidly penetrate the tongue epithelium of the frog, reach the papillary nerve fibers and contribute or modify gustatory informations.抄録全体を表示PDF形式でダウンロード (1314K) -
八谷 アツ子, 後藤 昌義, 津田 泰夫1978 年 28 巻 1 号 p. 47-61
発行日: 1978年
公開日: 2011/06/07
ジャーナル フリーThe nature of the inotropic actions of exogeneously applied ATP and related compounds (AMP-PNP, GTP, GMP and guanosine) was studied in comparison with that of adrenaline on the bullfrog atrial muscle under voltage clamped and unclamped conditions with the double-gap method.
ATP and GTP (10-6-10-3 M) produced an immediate positive inotropic effect similar to that achieved with adrenaline. Dose-response curves of these drugs fitted the theoretical dose-response relations, but the curves of ATP and GTP were not significantly altered by propranolol.Under voltage clamped conditions, ATP, AMP-PNP (non-hydrolyzable analogue of ATP) and GTP augmentated the calcium inward current (Ica), Ica-dependent tension and the delayed outward current (Ix) as adrenaline. On the other hand, GMP and guanosine, which have a purine-ribose base but not a high energy phosphate bond, produced a negative inotropic effect, and depressed the Ix as adenosine. All these nucleotides and nucleosides inhibited the Ica-independent tonic tension.The facts that GTP and AMP-PNP showed the same effect as ATP indicated that neither the energy liberation from the phosphate bond nor the substrate for cyclic AMP formation is involved in their positive inotropic effects. It is proposed that the energy rich nucleotides modulate the adenylate cyclase activity, being mediated by some receptor located at the outer surface of the membrane other than β-adrenergic receptor.抄録全体を表示PDF形式でダウンロード (3148K) -
林 秀生, 高田 真理, 有田 彰1978 年 28 巻 1 号 p. 63-73
発行日: 1978年
公開日: 2011/06/07
ジャーナル フリーEffects of cadmium on the electrical properties of frog skin were investigated by using the microelectrode technique. The epidermal application of 2 mM Cd for 5 min increased both the short circuit current and the skin potential, and decreased the skin resistance (RM). Cadmium also decreased intracellular potential with reference to the epidermal solution (PDi) and the electrical resistance between the epidermal solution and the tip of a microelectrode (RMi) located in the stratum germinativum.ΔRM that is RM, cd-RM, control seemed to approximately coincide with ΔRMi which is RMi, cd-RMi, control. Comparing with our previous results, i.e., Cd decreased RNa (the resistance to the active Na current) and increased RΣ(the resistance to the passive ions) but did not altered ENa (the electromotive force of active Na current) in the later stage (15 min or later). Cd seemed to decrease the RNa component at the epidermal side of the skin in the early stage (less than 5 min).抄録全体を表示PDF形式でダウンロード (1026K) -
松村 幹郎1978 年 28 巻 1 号 p. 75-87
発行日: 1978年
公開日: 2011/06/07
ジャーナル フリーThe effects of sudden changes in external Ca concentration on the time courses of the changes in size of the action potential and of the associated contraction in a single crayfish muscle fiber were investigated. Procaine-HC1 was added to the bathing solution to make the muscle fiber excitable. The concentration of the divalent cations (Ca and Mg) was high enough to keep the threshold potential constant. In Ca-free solution, neither action potential nor contraction was observed. When the external Ca concentration was suddenly increased from 0 to 14 mM, the full sized action potentials were generated within several seconds, but the tensions recovered slowly in an exponential time course with the time constants of 15-40 sec depending on the muscle fiber radius. The tension recovery was further delayed by addition of Dextran to the bathing solution, and it was also slowed at temperatures as low as 4-5°C. When the Ca concentration was changed from 14 mM to 0 mM, the decrease in action potential was slow rather than instantaneous. The delay in tension recovery was attributed to the diffusion time of Ca ions into the TTS, and it was suggested that the Ca entry through the TTS membrane was the first step in the excitation-contraction coupling of the crayfish muscle fibers. The diffusion coefficient of Ca ions inside the TTS was calculated from the recovery time of tension development. It was one order smaller than that in free solution.抄録全体を表示PDF形式でダウンロード (1351K) -
田崎 一二1978 年 28 巻 1 号 p. 89-108
発行日: 1978年
公開日: 2011/06/07
ジャーナル フリーElectric responses of extremely small amplitudes (1-30 μV peak-to-peak) repeating with more-or-less definite periodicity could be induced by a variety of chemical stimulants applied to squid giant axons either extracellularly or intracellularly. The chemical stimulants studied include allethrin, aminopyridines, N-bromosuccinimide, dimethylaminopyridine, glutaraldehyde, osmium tetroxide, parachloromercuribenzoate, rose bengal, scorpion venoms and veratridine. With several mild stimulants, it was possible to evoke periodic miniature responses unaccompanied by a fall in the resting membrane potential. The frequency of miniature responses could be lowered by intracellular injection of TEA (tetraethylammonium). These miniature responses could readily be suppressed by external application of TTX (tetrodotoxin). The miniature responses evoked by 4-aminopyrine were characterized by a large variation in the frequency of responses. Cross-linking of the membrane proteins with a dilute solution of glutaraldehyde produced miniature responses repeating at progressively falling frequencies. Analyses of the processes of production of miniature responses with these and other stimulants have clarified several aspects of the physicochemical properties of the excitable sites of the axon membrane.抄録全体を表示PDF形式でダウンロード (13021K)
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