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Biomedical subjects

T Tsubokawa

Publications and source records attributed to T Tsubokawa.

At least 181 records · Page 10Linked to original sources
PubMed1981

Evidence for involvement of the frontal cortex in pain-related cerebral events in cats: increase in local cerebral blood flow by noxious stimuli.

Noxious stimuli were shown to induce a remarkable increase in local cerebral blood flow restricted to the forepart of the cerebral hemispheres bilaterally anterior to the posterior sigmoid gyrus in cats. This increase in local cerebral blood flow was averted by lesions in the bilateral ventromedial thalamus and attenuated by pretreatment with an intraventricular injection of 6-hydroxydopamine.

Animals↗
PubMed1981

Long lasting suppression of firing of cortical neurons and decrease in cortical blood flow following train pulse stimulation of the locus coeruleus in the cat.

Single neuron activity and local cerebral blood flow were recorded simultaneously in the same spot of the gyrus proreus in cats. Train pulse stimulation (10-20 Hz, 30 sec) of the ipsilateral locus coeruleus induced long lasting suppression of firing in up to 78% of neurons and decrease in local flow, which lasted 1.9-5.6 min and 3.8-6.5 min, respectively. Single pulse stimulation evoked inhibition of firing in 55% of the neurons investigated.

Animals↗
PubMed1981

[Infusion test in the normal pressure hydrocephalus (author's transl)].

Continuous monitoring of the intracranial pressure and ventricular infusion test were carried out in 13 cases in which normal pressure hydrocephalus (NPH) was suspected. The infusion test was performed by intraventricular bolus injection of 8 ml of saline. The result was collated with the effect of shunting operation, which was judged by means of the improvement in the clinical symptoms and the amplitude of contingent negative variation. The excellent effect of shunting operation was obtained in the patients who showed the T of more than 200 sec, the compliance of less than 1.0 ml/mmHg, the conductance to outflow of less than 0.8 ml/mmHg/min and CSF outflow resistance of more than 15 mmHg/ml/min. In 3 cases out of the 5 effective cases, A or B wave was seen. However, appreciable variation of the values was shown among the cases so that it was concluded that the all-round-consideration must be done to select the case for the shunting operation with the findings in RI-cisternography, pneumoencephalography, computerized tomography and so on. This fact might indicate the existence of the complicated pathophysiology in NPH resulted from not only the impairment of cerebrospinal fluid circulation but also the disturbance of cerebral blood flow, changes in plasticity of the brain and so on.

Adult↗
PubMed1980

Changes in local cerebral blood flow and neuronal activity during sensory stimulation in normal and sympathectomized cats.

Activities of neurons of the thalamic relay nucleus and cortical somatosensory area which are capable of producing excitatory potentials in response to stimulation of the sciatic nerve were recorded, and local cerebral blood flow was measured simultaneously using a double microelectrode under local anesthesia in both non-pretreated cats and cats undergoing chemical denervation of the vasoadrenergic nerves by intraventricular injection of 6-hydroxydopamine (6-OHDA), in order to unmask the neural control on the cerebral vessels during increase of local metabolic rate. The results obtained may be summarized as follows. (1) A positive correlation was found between an increase in firing rate of a single neuron in the thalamic relay nucleus and somatosensory area and an increase in local cerebral blood flow following stimulation of the sciatic nerve. A distinct spatial and quantitative correlation was thus observed between neural activity and cerebral blood flow. (2) In 6-OHDA-pretreated cats, an increase in neuronal firing rate was observed following stimulation of the sciatic nerve, as it was in non-pretreated cats, but the concurrent response of local cerebral blood flow was seriously impaired. All these findings indicate that the increase in local cerebral blood flow occurring in association with increased neural activity does not result solely from increased local metabolism and a consequent increase in CO2 production, but requires for its occurrence that certain basic conditions be satisfied and maintained by the vasoadrenergic innervation.

Adrenergic Fibers↗