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Volume 44 (1992)
- Issue 4 Pages 229-
- Issue 3 Pages 155-
- Issue 2 Pages 83-
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Volume 44, Issue 3
Displaying 1-5 of 5 articles from this issue
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Effects on Arousal Reaction and Ev oked Muscular DischargesYasutami Masuda1992 Volume 44 Issue 3 Pages 155-168
Published: September 20, 1992
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe mechanism for the action of ketamine on the central nervous system was electrophysiologically studied in rabbits.
The following results were obtained.
1. When the brainstem reticular formation, the cerebral cortex and the hippocampus were stimulated by 100 Hz electric currents, the threshold intensity of a stimulus that could induce an arousal reaction and evoked muscular discharge was slightly elevated by administration of ketamine (1.0-10.0mg/kg). Because the ketamine-caused elevation in the stimulus threshold was minimal, the suppressive action of ketamine on consciousness and motor functions seemed to be mild.
2. Following a smaller dose of ketamine (0.3-0.5mg/kg), the stimulus threshold of the brainstem reticular formation, required for the induction of an arousal reaction, was reduced, while the recruiting response for the stimulation of the nucleus ventralis anterior thalami was markedly suppressed.
3. When the nucleus ventralis anterior of rabbits was first destroyed by electrocoagulation, the threshold intensity of a stimulus that could cause an arousal reaction was not reduced by administrating a small dose of ketamine.
The reduction in the st imulus threshold required for an arousal reaction, following small doses of ketamine, seems to represent a weakened suppressive action affecting the brainstem reticular formation after suppression of the diffuse thalamo-cortical projection system, including the nucleus ventralis anterior.View full abstractDownload PDF (4260K) -
Effects on Sciatic evoked eyelid microvibration, Nociceptive reflex muscular discharge, M-and H-waves and Photo-evoked eyelid microvibrationYasutami Masuda1992 Volume 44 Issue 3 Pages 169-178
Published: September 20, 1992
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSTo study the mechanism underlying the central effects of ketamine hydrochloride (hereafter, ketamine), as exemplified by its analgesic effect, the experiments on sciatic evoked eyelid microvibration (SMV), nociceptive reflex muscular discharge, M- and H-waves and photo-evoked eyelid microvibration (MV) were conducted in rabbits.
The following results were obtained.
1) Administration of small doses of ketamine (0.5mg/kg) induced a reduction in the amplitude of the SMV, with greater reductions in amplitude seen as the dose was increased (1.0-10.0mg/kg).
2) In rabbits in which the raphe nuclei had been previously destroyed by electrocoagulation, the ketamine-induced reduction in amplitude was smaller than that seen in the control group.
3) No significant change in the ketamine-induced reduction of SMV amplitude was seen in rabbits in which the thalamic nucleus ventralis anterior (VA) had been previously destroyed by electrocoagulation or in rabbits which the cerebral cortex had been anesthetized with xylocaine, compared with the control group.
These results indicate that ke tamine has strong analgesic effects, with the raphe nuclei directly or indirectly involved in this analgesic effect, whereas the VA and cerebral cortex are not involved.
4) The amplitude of the additional waves in the nociceptive reflex muscular discharge resulting from stimulation of the sciatic nerve was markedly reduced by administration of small doses of ketamine (0.3mg/kg). Thus, it was shown that ketamine inhibits polysynaptic reflex.
5) The amplitude of M-and H-waves did not show remarkable changes after ketam ine was administered, indicating that this agent does not affect monosynaptic reflex or the neuromuscular junction.
6) The amplitude of the photo-evoked eyelid microvibration increased with small doses of ketamine (0.3-0.5mg/kg), but decreased slightly when the dose was increased (1.0-10.0mg/kg). Thus, it was confirmed that ketamine has only a slight effect on consciousness.View full abstractDownload PDF (1704K) -
Mineo Matsubara, Megumi Sakai, Kazutoshi Yamagami, Yasuhide Kitazawa, ...1992 Volume 44 Issue 3 Pages 179-183
Published: September 20, 1992
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSIn regard to 65 patients brought in for acute poisoning during the last 5 years, we studied patient background, termination, patient transport, causative agent, number of days of hospitalization, treatments given, and suicides, and found that there were a large number of suicides as well as a large number of repeated atteliapters. Therefore, we thought that it is necessary to make efforts in providing psychiatric treatment as well as defensive measures to cut off the route of obtaining the poison. When the patient is brought in, it was found that in relatively many ceses there was a delay in diagnosis and aggravation of symptoms due to mistaken treatment, so that it was thought necessary to carry out enlightenment of treatment methods for poisoning patients in primary institutions and also to take action against the belated development of toxicology studies here in Japan. However, as one cause it was thought that since at the time of hospitalization of poisoning cases vital signs are relatively stable, it is difficult to adequately judge the seriousness of the case. In regard to treatment, as to paraquat there is at present no effective treatment method, and it is thought that the expulsion of paraquat at the earliest possible period should be effected as the only possible treatment.View full abstractDownload PDF (715K) -
[in Japanese]1992 Volume 44 Issue 3 Pages 214-218
Published: September 20, 1992
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSDownload PDF (6835K) -
[in Japanese]1992 Volume 44 Issue 3 Pages 219-227
Published: September 20, 1992
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSDownload PDF (13209K)
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