1. Intracellular potentials were recorded from 164 cells in cat precruciate cortex, and their responses were examined during the phasic and tonic phases of EEG arousal. 2. According to the initial responses corresponding to phasic EEG arousal, these cells were classified into 71 E (excitation), 49 I (inhibition), 38 DF (disfacilitation), and 6 DI (disinhibition) cells. 3. The late responses corresponding to tonic EEG arousal varied among these cells. Thirty-two of the 164 cells were unresponsive. Of the remaining cells, 102 showed excitation, 16 inhibition, 12 disfacilitation, and 2 disinhibition. These cells were retermed+E, +I, +DF, and +DI cells, respectively. 4.+E cells were located at all depths through laminae I to VI, but the majority were found in laminae III_b-VI.+I cells were between lamina I and the lower half of lamina III (III_b), and +DF and + DI cells were between lamina I and the upper half of lamina III (III_a). From these characteristic layer distributions it is postulated that an upward cascade transmission from deep to superficial layers occurs during tonic EEG arousal. 5. Nine types of combinations of the initial and late responses were found: E, I, DF or DI with+E, E or I with+I, E or I with+DF, and I with+DI. To explain these various activity patterns, an ‘arousal’ circuit model was proposed by combining the downward an upward cascade transmission patterns. The elementary structure of cortical arousal was thus formulated, and discussed from the developmental aspect of behaviour.

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In the guinea-pig mesenteric artery, reduction in [Na]_o by30mM (substituted by choline or sucrose;137mM [Na] _o in Krebs solution) generated contraction with no change in membrane potential.In NaClfree solution (15mM [Na] _o), the amplitude of phasic contraction reached 0.8times the contraction evoked by118mM [K] _o with only a slight depolarization. In NaCl-free solution, the amplitude of phasic contrlction evoked by noradrenaline (NA) 5×10^-5M or caffeine5mM increased to roughly twice the amplitude of the contraction evoked in the control solution. In Ca-free solution, the K-, NaCl-free-orNa-free-induced contractions rapidly ceased, but NA-inducfd contraction ceased within5min and the caffeine-induced contraction persisted for more than15min.In a skinned fiber, increase of [Na] _o from10to60mM suppressed the pCa-tension relationship in the ranges of10^-7and 10^-5M free Ca but not with a dose of 30mM [Na] _o.NA (10^-5M) had no effect on skinned fibers. Increase in Na concentration (60mM) had no effect on Ca accumulation in the store site or on Ca release by caffeine.Possible Na-related mechanisms on the development of mechanical response are discussed in relation to Ca onthe surface and in the internal membrane structure.The NaC1- free-induced contraction in smooth muscles of the guinea-pig mesenteric artery is postulated to be due to influx of Ca through the Na channel, rather than the Ca channel.

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The C-terminal octapeptide of cholecystokinin (CCK-8) injected into the lateral ventricle of rats produced a lowering of body temperature. CCK-8 potentiated pentobarbital-induced hypothermia, but not the ethanol one. Thyrotropin releasing hormone (TRH) and prostaglandin E₂ (PGE₂) antagonized the hypothermic effect of CCK-8. Non-sulfated CCK-8 was ineffective in lowering body temperature, indicating that sulfated tyrosine in the CCK molecule is indispensable for its hypothermic action. Caerulein was found to possess rather less activity compared with CCK-8.

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A high-frequency ventilator was designed using a loudspeaker as a piston, driven by a power-amplifier. A sine-wave signal was introduced into the amplifier from an electronic oscillator. The mechanical and gas exchange characteristics of the ventilator were studied in vitro and in dogs.
The volume output per stroke, when open to air, was between 100 and 200ml up to 7Hz, then gradually decreased as the frequency increased. A Wright respirometer appeared to measure the volume flow fairly accurately up to 14Hz. The pressure output against a closed volume of 1.1 liters achieved a maximum of 29mmHg at 7Hz. It gradually decreased as the frequency was changed from 7Hz. The loudspeaker worked in such a way that the volume output decreased considerably when it was forced to move against a closed space to generate pressure.
Adequate ventilation was achieved in all dogs from 1.4 to 10Hz. At 14Hz, the results were variable, and at 20Hz and above, gross hypoventilation always resulted. The P ao ₂, values were always over 440mmHg when 0.8 liter/(kg·min) of oxygen was supplied into the respiratory circuit.
A speaker ventilator has the advantage of easy assembly and the possibility of applying various flows by electrical control. Its disadvantages are a lack of power and the difficulty in establishing ventilatory volumes without actual measurement.

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The transvascular fluid shift after blood volume modification was analyzed by means of continuous blood volume determination and simulation analysis. On splenectomized dogs, 15% of the circulating blood was withdrawn and retransfused, while the circulating blood volume, hematocrit and colloid osmotic pressure were continuously monitored. Based on the results, the transvascular fluid shift was simulated by a two-compartment model. The compliance of the intravascular and interstitial fluid spaces as well as the transvascular filtration coefficient was determined on the whole body, simultaneously. No statistically significant differences were found between any of the values for blood withdrawal and retransfusion. The compliance of the vascular space, 4.62±0.82ml/mmHg⋅kg of body weight, was almost identical with that of the interstitial fluid space, 4.75±1.52ml/mmHg⋅kg of body weight. The whole body capillary filtration coefficient was 0.74±0.39ml/ min⋅mmHg⋅kg of body weight, which is within the range of the reported values of the capillary filtration coefficient for muscle and intestine. It is suggested that the rapid transvascular fluid shift after blood volume modification is provided with the fact that the compliances of intravascular and interstitial fluid spaces are almost identical.

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Through daily electrical stimulation of one of the hippocampi in the rabbit, EEG spikes were “kindled” in both hippocampi. Such hippocampi (termed kindled hippocampi) were then studied with the microelectrode in acute experiments. The electrical activities of the kindled hippocampus were characterized by spontaneous occurrence of hyperpolarizing potentials of various magnitudes (3-27 mV) and various durations (50-600 msec) in the pyramidal cell. These hyperpolarizations were never preceded by a prolonged spike burst. Furthermore, they could occur without any preceding depolarizations. They consisted of two components, i.e., Cl-dependent (somatic inhibitory postsynaptic potential) and Cl-non-dependent (dendritic hyperpolarization) components. They were the main abnormal events occurring within the pyramidal cell of the kindled hippocampus. It was therefore considered that they were the intracellular correlates of the EEG spikes.

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The role of ions in the generation of taste nerve responses to electric currents was studied by examining integrated responses and single fiber discharges of the chorda tympani nerve to chemical and electrical stimulations of the tongue in rats.
Integrated chorda tympani responses to anodal currents were suppressed after cessation of the blood flow to the tongue and on application of FeCl₃ to the tongue surface. These findings indicate that electric currents do not stimulate the nerve directly but activate taste cells to evoke neural discharges. Magnitude of the integrated response to anodal current decreased with a decrease in concentration and with an increase in flow rate of the bathing solution applied over the tongue during electrical stimulation. All the chorda tympani fibers responsive to a certain electrolyte responded to anodal or cathodal current in the presence of the same electrolyte at its subliminal concentration in the flow chamber. However, there were a few fibers which did not respond to a few electrolytes, but responded to currents in the presence of either one of the electrolytes even at their much lower concentrations. Across-fiber correlations between the responses to chemical stimuli and anodal currents in the presence of the chemical solutions in the flow chamber indicated that responsiveness to anodal current was not always dependent on species of cation in the bathing solution. From these findings, we assume that the response to electric current is due to the effect of electrophoretically carried ions on not only specific but also non-specific receptor mechanisms for the ions.

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Micropore passability of fresh human blood was measured by means of an improved Nuclepore membrane filter method under varying concentrations of electrolytes and proteins in the plasma. The method gives an average pore passage time required for single red blood cells to flow through 5μm pores of the filter membrane. Micropore passability is reduced with increasing ionic osmolarity above 320 mOSM when the protein concentration is normal. However, it remains constant up to 370and 430 mOSM when the protein concentration is lowered to 1/3 and 1/6 of normal, respectively.
Furthermore, when red blood cells are added to an hyperosmotic plasma, the protein concentration detectable in the plasma is reduced to a level lower than expected from a simple osmotic water shift. The excess reduction in the protein concentration is nearly proportional to the amount of added red blood cells. The following succession of events was assumed in order to interpret these results. An electric repulsive force between red blood cells and plasma proteins is weakened by an increased ion concentration. This reduction in the repulsive force will increase the adsorption of proteins on the surfaces of the red blood cells. The adsorbed proteins will restrict cell membrane flexibility, causing a reduced micropore passability of red blood cells.

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The relationship between the effective intracapillary pressure and the effective pericapillary pressure following blood withdrawal and retransfusion was studied. Change in the effective pericapillary pressure was estimated from the transcapillary pressure difference determined from the amount of transcapillary fluid shift and the effective intracapillary pressure. The estimated alteration in the effective intracapillary pressure ranged from 1 to 7 mmHg in blood withdrawal and retransfusion (15% of estimated blood volume). The transcapillary pressure difference, or effective pressure gradient for fluid movement between intracapillar and pericapillary space, was within about 0.5 mmHg when the whole body filtration coefficient obtained by us was used. The effective pericapillary pressure closely followed the effective intracapillary pressure. In other words, change in intracapillary pressure elicits a rapid shift of vascular or interstitial fluid and the effective pericapillary pressure equilibrates rapidly with the intracapillary pressure.

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During 90 min of spontaneous or controlled CO₂ breathing in splenectomized dogs, the acid-base parameter changes of the thoracic duct lymph were compared with those of the arterial and postcaval venous blood.(1) The lymph reached an apparent steady state in the acid-base parameters at least 10min after the blood.(2) The lymph bicarbonate concentration gradually increased almost in parallel with the lymph P_CO2 elevation, while the raised plasma bicarbonate concentration remained nearly unchanged until the end of CO₂ inhalation.(3) The in vivo buffer slope of the lymph increased strikingly within 10min, reaching three times the in vitro slope at 90min after inception of CO₂ breathing. After 10min, the lymph value became higher than the venous value, suggesting early cellular contribution to ECF buffering.(4) Considering the lymph values as representative of the interstitial fluid values, cellular contribution to ECF buffering was computed; they were 7.8, 15.6, and 10.7% in the spontaneously breathing group, and 8.9, 10.6, and 12.0% in the controlled ventilation group at 30, 60, and 90min of CO₂ breathing, respectively.

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Isolated hypogastric nerve-vas deferens preparations from guinea pigs were used in vitro to detect effects of plasma solutes from a nephrectomized rabbit or uremic patients on nerve-mediated contractions. Plasma collected from the subjects was ultrafiltered and applied directly to the tissue in an organ-bath at 34-36°C. Plasma solutes with molecular weights (M.W.) smaller than 500 depressed contractions, their potency being greater when derived from the anephric rabbit and from patients than from the healthy control. Plasma solutes with a M.W. of 500-10, 000 from the healthy rabbit augmented contractions, whereas those from the anephric rabbit depressed them. Human plasma solutes with a M.W. of 500-5, 000 or 5, 000-10, 000 exhibited no effect except a slight depression by those with a M.W. of 500-5, 000 from uremic patients. High M.W. plasma solutes (10, 000-20, 000 daltons) from the patients were also found to depress contractions more strongly than those from healthy men. It is concluded that uremic metabolites capable of depressing peripheral autonomic functions accumulate in the nephrectomized rabbit and in patients with renal failure, and the degree of depression varies with the difference in M.W. of the metabolites.

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Circadian rhythm of spontaneous locomotor activity, which is normally highly elevated during the dark phase of a day, diminished after ablation of the vagal nerves in rats with intact suprachiasmatic nuclei under light-dark cyclic conditions. This suggests that gastrointestinal activity affects the circadian rhythm of locomotor activity through the afferent pathway of the vagus.

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The relative Cl permeability in the erythrocyte membrane of the dystrophic chicken was estimated from the potential changes measured optically by a fluorescent dye. The reduced Cl conductance relative to the K conductance induced by a constant concentration of valinomycin was suggested in the dystrophic erythrocyte membrane in comparison with that in the control.

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