Measurement of respiratory function using whole-body plethysmography in unanesthetized and unrestrained nonhuman primates.

Extended term, continuous measurement and observation of drug responses were performed to examine the feasibility of a custom-made whole-body plethysmograph for measuring respiratory function in unanesthetized, unrestrained monkeys. Using this apparatus, respiratory function (respiration rate, tidal volume, and minute volume) was observed for 23 hr in unanesthetized, unrestrained cynomolgus monkeys (Macaca fascicularis). The respiration rate, tidal volume, and minute volume in the light period (7:00 to 19:00) reached approximately 30% to 50% higher values than in the dark period (19:00 to 7:00), thus clearly exhibiting circadian variation in the cynomolgus monkey respiratory functions.

Effects of benzene in a micronucleus test on peripheral blood utilizing acridine orange-coated slides.

A micronucleus test was conducted on the peripheral blood of mice and rats utilizing acridine orange-coated slides (AO-coated method) after oral administration of benzene. Blood was sampled at 0, 24, 48, and 72 h after administration of benzene at doses of 500, 1000, and 2000 mg/kg in both mice and rats. The highest occurrence of micronucleated reticulocytes (MNRETs) was observed at 48 h after administration in both species.

Administration-route-related differences in the micronucleus test with benzene.

The effect of route of administration on the outcome of the micronucleus test was studied in 2 laboratories by administering the model chemical benzene intraperitoneally (i.p.) and orally (p.

Ouabain susceptibility of heart muscle of the house musk shrew, an insectivore: a comparison with the rat, guinea pig and rhesus monkey.

The susceptibility to ouabain of the heart muscle of the house musk shrew (Suncus murinus), an insectivore, was investigated by means of in vitro experimentation, and compared with the rat, guinea pig, and rhesus monkey. Contraction of the electrically driven heart muscles of all species slowly increased following application of ouabain. The shrew was approximate 100-fold more sensitive than the rat and 10-fold less than the guinea pig and rhesus monkey.