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Biomedical subjects

T Ookawa

Publications and source records attributed to T Ookawa.

At least 19 recordsLinked to original sources
PubMed1978

Visual evoked potentials from the superficial Wulst of the cockerel to intermittent flash stimulation of various frequencies.

Averaged visual evoked potentials (VEPs) from the surface of the Wulst and the electroretinogram (ERG) were recorded simultaneously in curarized cockerels. The polyphasic VEPs were recorded from the dorso-medial region of the Wulst of cockerels at 1 Hz stimulation, while the ERG consisted of the a, b, and c waves. The late VEPs were markedly attenuated with an increase in the stimulation frequency.

Animals↗
PubMed1977

Behavioral and electroencephalographic manifestations of avian epilepsy: a review of the literature.

Recently, electrophysiological studies on sleep and wakefulness in birds have yielded useful results. Furthermore, recent evidence obtained in behavioral and electroencephalographical investigations of epileptic birds, induced neuropharmacologically or genetically, have led to recognition of the fact that epileptic seizures are present in aves, and that these seizures reveal many similarities between mammalian and avian epilepsy. While the investigation of birds is of obvrious value for demonstrating the neuropharmacological interrelationship with the brain, comparison of the correlation between abnormal behavior and the electroencephalogram in birds and higher vertebrates requires further research. In the present paper, normal and abnormal electroencephalographic activity associated with behavior of birds is reviewed. It was concluded that birds provide a useful preparation for studying experimental epilepsy.

Animals↗
PubMed1976

Strychnine convulsions in cockerels.

An intravenous injection of 0.85 mg/kg strychnine nitrate produced typical convulsions in all cockerels, aged 4 to 12 weeks, as well as adult hens. Convulsions consisted of an initial excitement, tonic stage associated with opisthotonos, transient clonic movement, and finally vigorous tonic convulsions. Strychnine spikes in the Wulst EEG were not induced by the same intravenous does of strychnine in both cockerels and adult hens.

Animals↗
PubMed1976

Behavioral and physiological studies of seizures induced by systemic injection of metrazol in chickens.

The influence of systemically administered Metrazol on behavior, electroencephalogram and body temperature has been studied in young and adult chickens. Distinct convulsions were induced by 30--50 mg./kg. Metrazol administered intravenously in adults: they consisted of an initial excited state, a tonic convulsion accompanied with opisthotonos, and finally, convulsive movements. During recovery from these convulsions, three distinct behaviors were observed: violent peck-like movement, watchful state and finally panting behavior. All of the birds receiving higher intravenous doses (60--100 mg./kg.) exhibited vigorous convulsions immediately after injection and death occurred in 100% of the birds receiving these doses. An intraperitoneal injection of 75--100 mg./kg. Metrazol produced typical convulsions in young and adult chickens. At these doses, convulsions consisted of an initial excited state, a tonic convulsion accompanied with opisthotonos, and convulsive movements which involved clonic and tonic phases. The threshold for evoking typical convulsions with intraperitoneal injection ranges between 50 and 60 mg./kg. Metrazol in young chickens. The intravenous threshold doses for evoking high amplitude (1--2 mV.) in the EEG of adult chickens was 60 mg./kg. Metrazol. High intraperitoneal doses of Metrazol(75-100 mg./kg.) produced typical spikes with large amplitude which were synchronous in the two hemispheres in both young and adult chickens. There was a marked increase in body temperature within 10 minutes after injection in all cases of 50 mg./kg. intravenous dose: maximum increase (at 40 min.) was 1.5 degrees C. as compared with controls, however, it decreased rapidly with panting behavior. The highest does (100 mg./kg.) produced a maximum increase in body temperature of 3 degrees C. Discussion of epileptic seizure susceptibility to Metrazol in aves, in the light of phylogenesis, is discussed.

Animals↗