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S Kobayasi

Publications and source records attributed to S Kobayasi.

At least 37 records · Page 2Linked to original sources
PubMed1981

Electrophysiological evidence for multiple sites of actions of angiotensin II for stimulating paraventricular neurosecretory cells in the rat.

Microelectrophoretically (MEPh) applied angiotensin II (AII) excited about half of the PV neurosecretory cells recorded. The excitation was blocked by MEPh applied Sar1-Ala8-AII. Intraventricular (IVT) injection of AII excited both the sensitive cells and insensitive cells to the MEPh applied AII. MEPh-applied Sar1-Ala8-AII, however, blocked the IVT AII induced excitation only in the former type of the cells.

Angiotensin II↗
PubMed1981

Effect of body temperature on respiratory frequency in vagotomized rabbits.

The temperature coefficients of the fundamental central respiratory frequency (fo), cycle duration (Tco), and inspiratory duration (TIo) were estimated, and their values were 5.3, -5.3 and -2.7, respectively. These results suggest that the fundamental respiratory pacemaker is under the influence of some thermosensitive mechanisms or is thermosensitive by itself, while the mechanism controlling the inspiratory duration is unaffected by thermosensitive mechanisms.

Animals↗
PubMed1980

Responses of paraventricular and supraoptic units to angiotensin II, sar1-ile8-angiotensin II and hypertonic NaCl administered into the cerebral ventricle.

Extracellular recordings of action potentials were made from neurones antidromically identified as neurosecretory cells in the paraventricular and supraoptic nuclei of urethane-anesthetized female rats. Eighty-six neurones were examined for their responsiveness to 10 ng of angiotensin II (AII) injected into the third cerebral ventricle and 78 (91%) of them increased their firing rate following the AII injection. None of the neurosecretory cells tested showed a response to the intraventricular (IVT) injection of isotonic NaCl. Thalamic neurones and non-neurosecretory hypothalamic neurones did not respond to the AII given IVT. Firing activity of 13 neurosecretory neurones was recorded during reflex milk ejection induced by suckling pups in the lactating rats. Seven of them were classified as oxytocinergic cells because they showed a burst of activity before reflex milk ejections and the remaining 6 neurones which gave no burst of firing before milk ejections were classified as nonoxytocinergic neurones. The IVT application of AII resulted in activation of all the oxytocinergic neurones and 5 of the 6 non-oxytocinergic neurones. The effect of AII on the firing of the neurosecretory cell was inhibited by the simultaneous application of Sar1-Ile8-AII (1 microgram), a competitive AII antagonist. The IVT injection of the antagonist alone inhibited the spontaneous firing of the neurosecretory cells, but it did not affect the firing of thalamic or non-neurosecretory hypothalamic neurones. Hypertonic NaCl (0.85 M NaCl, 1 mu1 IVT) also activated 13 of 20 neurosecretory cells tested. Combined application of AII and hypertonic NaCl elicited a marked potentiation of the response of neurosecretory cells to each of the stimuli. These findings indicate that AII activates neurosecretory cells stimulating specific AII receptors in the brain and that AII has a synergistic action with hypertonic NaCl. Inhibition of spontaneous activity of neurosecretory cells by a competitive AII antagonist suggests that endogenous AII may participate in the maintenance of basal activity of neurosecretory cells.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1979

Phrenic activity during severe hypercapnia in vagotomized rabbits.

The central control mechanism of respiratory frequency under varied alveolar carbon dioxide pressure (PACO2 20--200 Torr) was investigated in anesthetized, vagotomized, immobilized, and artificially ventilated rabbits. Central inspiratory activity indicated by phrenic motor discharge was tolerant of the extensive hypercapnia. Under light anesthesia the respiratory frequency (f) decreased in a hyperbolic fashion with increasing PACO2. Under deeper anesthesia or after mesencephalic decerebration the hyperbolic f response to PACO2 was abolished or changed to a hill-type f response (initial increase and subsequent decrease in f) and, on the average, the changes in frequency were much less. We conclude that in the absence of vagal control the respiratory frequency is primarily determined by 1) the periodicity of the bulbopontine inspiratory activity, which is little dependent on PACO2, and 2) a suprapontine acceleratory mechanism, which is depressed by increased PACO2 and highly sensitive to anesthetics. The mechanism of changes in the type of f response to CO2 is discussed.

Anesthesia, General↗
PubMed1975

Electric birefringence of myosin subfragments.

Electric birefringence measurements have been made on aqueous solutions of myosin subfragments, heavy meromyosin, subfragments 1 and 2 (S-1 and S-2). All of these showed positive electric birefringence. Heavy meromyosin and S-2 showed a large intrinsic Kerr constant. From the analysis of the build up and decay process of the birefringence, the contribution of the slow induced dipole moment was concluded in heavy meromyosin and S-2, although the existence of the permanent dipole moment was not completely excluded. The decay process of the birefringence of heavy meromyosin was found to consist of two components; the fast one of which had a relaxation time of the same order as that of S-1. This is probably due to the presence of a flexible hinge in heavy meromyosin.

Adenosine Triphosphate↗
PubMedDate not supplied

Invasive enteritis by Strongyloides stercoralis presenting as acute abdominal distress under corticosteroid therapy.

Overwhelming helminthiasis is still a problem in endemic areas, especially in immunocompromised patients. We report a case of invasive intestinal strongyloidiasis that was clinically expressed as acute abdominal distress in a 73-year-old man from São Paulo who had been receiving methylprednisone, 20 mg/day, for one year for osteoarthritis. A surgical specimen from the ileum revealed invasive enteritis with severe infestation by Strongyloides stercoralis. The patient died of sepsis 6 days after surgery. The possibility of invasive strongyloidiasis should be considered in the differential diagnosis of acute abdominal distress in patients undergoing immunosuppressive therapy.

Abdomen, Acute↗