PubMed Health⌕ Search

Biomedical subjects

R Kishi

Publications and source records attributed to R Kishi.

82 records · Page 5Linked to original sources
PubMed1982

Regional distribution of lead, zinc, iron and copper in suckling and adult rat brains.

The flameless atomic absorption method was applied to reveal regional differences in heavy metals between suckling and adult rat brains. The lead concentrations in the suckling brains were considerably different from those in the adult rats. The levels of lead concentration in the cerebrum and cerebellum of the normal suckling rats were 3-4 times higher than those of adult rats. Iron concentrations in the cerebrum of the suckling brains were approximately half those in the adult brains. Zinc and copper concentrations in medulla from the suckling rats were higher than those in the same region from the adult rats.

Aging↗
PubMed1980

Effects of infrasound on the rota-rod treadmill performance of rats.

The present study was designed to evaluate the effects of infrasound on behavioral performance in rats. The rats were divided into two groups, one selected for good performance (six rats: superior group) and the other for poor performance (six rats: inferior group) on the Rota-rod Treadmill. Exposure conditions were as follows: Exp. 1 Control (150 min), Exp. 2 Exposure to infrasound with a main frequency of 16 Hz and a sound pressure level of 105 dB (S.P.L.) (70 min), Exp. 3 Exposure to infrasound with a main frequency of 16 Hz and a sound pressure level of 95 dB (S.P.L.) (70 min), Exp. 4 Exposure infrasound with a main frequency of 16 Hz and a sound pressure level of 85 dB (S.P.L.) (150 min), Exp. 5 Exposure to infrasound with a main frequency of 16 Hz and a sound pressure level of 75 dB (S.P.L.) (150 min), Exp. 6 Exposure to Pink Noise of 72 dB (A) (70 min). Comparison of the pre-exposure endurance time (Maximum: 2 min) on the Rota-Rod Treadmill with endurance after exposure to infrasound showed that the endurance time of the superior group after exposure to 16 Hz, 105 dB was not reduced. The endurance of the inferior group was reduced by exposure to 16 Hz, 105 dB after 10 min, to 16 Hz, 95 dB after 70 min, and to 16 Hz, 85 dB after 150 min.

Animals↗
PubMed1980

Behavioural effects in rats following repeated exposure to methyl bromide.

Rats were exposed to methyl bromide (MB) at concentrations of 200 ppm and 300 ppm, 4 h per day, 5 times weekly, for 3 weeks. After the final exposure, behavioural tests for emotional response equilibrium function, the function of the peripheral nerve and the circadian rhythm of spontaneous activity were performed. Relatively prolonged dysfunction of the peripheral nerve as well as disturbance of the circadian rhythm of spontaneous activity were observed.

Animals↗
PubMed1978

[Behavioral changes in the rats following inhalation of mercury vapor (author's transl)].

The present study was designed to determine critical brain mercury concentrations associated with specific behavioral changes during exposure to mercury vapor. Rats exposed to 3 mg of Hg/m3 for 3 hours, 5 days per week, for 15-42 weeks, showed a decline in conditioned avoidance response. The latency of escape response also increased in pole climb shock escape. The time to the onset of effects varied from 12 to 39 weeks among 14 rats exposed to mercury. All rats recovered to preexposure baseline within 12 weeks after the termination of exposure. A significantly poor behavioral performance was noticed in rats with brain mercury concentration of approximately 20 microgram Hg/g. Behavioral recovery was seen when the mercury concentrations decreased to 10 microgram Hg/g brain tissue. These results suggest that the critical concentration of inorganic mercury in the brain associated with behavioral changes in the rat ranges about 10 ppm to 20 ppm. In spite of the high concentration of mercury, the nervous tissues of rats in this experiment with mercury vapor intoxication were normal.

Animals↗
PubMedDate not supplied

Effect of prenatal exposure to styrene on the neurobehavioral development, activity, motor coordination, and learning behavior of rats.

Maternal Wistar rats were exposed via inhalation to 0, 50, or 300 ppm styrene for 6 h/day during gestation days 7 to 21, and offspring were subsequently evaluated in several neurobehavioral tests. Preliminary results with a small number of litters revealed significant dose-dependent effects in tests performed prior to weaning (surface righting, pivoting locomotion, and bar holding), as well as in tests performed after weaning (motor coordination, open-field behavior, and motor activity). Exposure to low concentrations of styrene (50 ppm) caused disturbances in motor coordination in addition to delaying some motor and reflex developments. Large doses (300 ppm) led to changes in open-field behavior and increases in spontaneous activity in addition to the delay in neurobehavioral developments. Exposure of dams to styrene did not clearly affect the learning behavior of the offspring. It was also observed that age played a role in the differences in styrene's effects on neurobehavioral function. Only subtle effects were found in both open-field behavior and motor-coordination function when compared with control rats at 120 days of age. These results suggest that the functional neurobehavioral development of progeny of dams exposed to styrene (or other solvents) should be further investigated.

Animals↗
PubMedDate not supplied

Effects of low lead exposure on neuro-behavioral function in the rat.

Small doses (45-180 micrograms/g) of lead acetate were administered to male rats by gavage every day during the first 3 wk of life. A blood concentration of approximately 59 micrograms/100 ml blood produced signs of disturbances in reflex development and some changes in emotional behavior. Larger doses resulted in subtle changes in the neuromotor coordination function. The effect of low levels of lead exposure on the cognitive function in operant conditioning could not clearly be observed. Brain lead concentration tended to be higher than in other tissues examined. At approximately 10 months following cessation of lead acetate administration, the brain lead concentration had decreased to almost the same level found in control rats, and no distinguishable differences were observed between the lead-treated rats and controls in emotional behavior and neuromotor coordination.

Animals↗
PubMedDate not supplied

Slow learning in rats due to long-term inhalation of toluene.

Rats were exposed to toluene at the concentrations of 1,000, 4,000 and 7,000 ppm for 1 hr a day, 6 days a week for 6 months and a half; 154 days' exposure. Behavioral tests on a test battery were carried out after the termination of 154 days' exposure. The performance level of FR 1, extinction of the FR 30 schedule, wheel running activity, scores of open field test and body weight were not influenced. Slow acquisition of the timing behavior of the DRL 12 sec schedule in toluene-exposed rats was revealed: higher responses from the 1st session onwards, lower percent reinforced responses from the 1st session onwards and higher relative frequency of shorter interresponse-time (IRT) from the 9th to 12th sessions, respectively than those of the control rats. At the 33rd session onwards, the highest relative frequency of IRT of the DRL 12 sec schedule was at around 12 sec in all groups except one exposed group (7,000 ppm).

Animals↗