Myoendothelial and placental blood flow responses to ritodrine infusion in the guinea pig

Chronic measurement, using a Doppler probe, of uterine artery flow in the gravid guinea-pig

“…The advantages of these animals include economy, a haemomonochorial placenta (labyrinth type), cyclic changes in serum oestrogen and progesterone concentrations qualitatively similar to those observed in women, and cardiovascular/respiratory alterations during pregnancy analogous to those in women (Enders, 1965;Challis, Heap & Illingworth, 1971;Martensson, Sjoquist, Bjellin & Carter, 1979; Hosenpud, Hart, Morton, Hohimer & Resko, 1983;Morton et ai, 1984). However, the animal's small size has proved a disadvantage in studies requiring blood flow measurement.…”

Effect of noradrenaline on circulation in the genital tract of early and late pregnant guinea-pigs

“…pentobarbitone sodium. The animal was handled and surgically prepared as previously described (Sjöquist, Bjellin & Carter, 1977;Màrtensson, Sjöquist, Bjellin & Carter, 1979) except that artificial ventilation was avoided. A polyethylene catheter (o.d.…”

Continuous measurement of blood gas tensions in the fetal guinea pig by mass spectrometry

“…Catheters were also placed in the opposite femoral artery and a jugular vein to enable registration of arterial blood pressure and for the subsequent infusion of noradrenaline. A detailed description of these procedures has been given elsewhere [15]. The abdomen was opened by a midline incision and the Uterus, wrapped in plastic foil, was placed on a thermostatted table, äs recommended by KASTENDIECK and MOLL [12].…”

“…The first measurement served äs a control for the second determination, which was made during the intravenous infusion of noradrenaline bitartrate (10-20 g/min/kg). On each occasion 6 · l O 5 -7 · l O 5 microspheres were injected in the left ventricle whilst a reference sample of blood was withdrawn at a constant rate from the femoral artery [15]. At the conclusion of the experiment, the fetal thorax was opened to ascertain the position of the blood gas catheter tip.…”

“…The radioactivity in the organs and in the reference samples of blood was measured in a gamma spectrometer with a three inch crystal and a multichannel analyzer. Cardiac Output and organ blood flows were derived äs earlier described [15]. Two experiments were rejected because a comparison of right and left renal perfusion suggested uneven distribution of the microspheres.…”