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Biomedical subjects

F Palecek

Publications and source records attributed to F Palecek.

At least 37 records · Page 2Linked to original sources
PubMed1985

Electromyographic activity of expiratory muscles in the rat.

We examined the participation of expiratory muscles on breathing in the rat. The experiments were performed on 16 male rats in halothane [1.5%] or urethane [1.3 g/kg i.p.] anaesthesia. We recorded the electromyographic [EMG] activity of intercostal and abdominal muscles with a concentric needle electrode during quiet breathing, breathing against increased pressure in the airways and during the expiration reflex. In halothane anaesthesia the EMG expiratory phasic activity was observed only in internal intercostal muscles in 40% of spots examined during quiet breathing and in 58.5% when breathing against increased pressure. The EMG activity during the expiratory reflex was difficult to evaluate. In the abdominal muscles permanent EMG activity was found in 66% of trials. In urethane anaesthesia no phasic expiratory EMG activity was observed in intercostal or abdominal muscles. In abdominal muscles in 9% of trials a permanent activity was found.

Anesthesia↗
PubMed1985

[Postnatal development of the Hering-Breuer reflex in the rat].

The intensity of the Breuer-Hering inflation reflex was studied in newborn (1 day old), in young (8 days old) and in adult rats (90 days old) under urethane general anaesthesia (1.3 g/kg i.p.). The inflation pressure was adjusted with the aid of a water-valve. The reflex was present in all 3 age groups. An inflation pressure of 0.2 kPa applied in the course of expiration produced a long lasting apnoea in newborn rats which lasted 48 normal respiratory cycles. An inflation pressure of 0.5 kPa in young rats induced an apnoea lasting for only 3 normal respiratory cycles, whereas a pressure of 1 kPa in adult rats led to an apnoea which lasted for 20 normal respiratory cycles. The compliance of the respiratory system in relation to lung weight is approximately 5 times higher in adult rats compared with that of newborn rats. It is approximately double in comparison with young rats. The pressures of inflation mentioned in the 3 age categories can be considered as equieffective from the point of stimulation pulmonary stretch receptors. It can be concluded from these findings that the reflex of Breuer-Hering in newborn rats is more potent in comparison with adult rats, but it is lower in young rats at the age of 8 days. It is suggested that the differences observed are due to functional and anatomical maturation.

Animals↗
PubMed1984

Functional residual lung capacity in rats affected by a carotid body stimulant.

The respiratory response and changes of functional residual lung capacity were measured in the rat after intravenous administration of the drug S 2620 in a dose of 0.4 mg/kg. This substance induced a significant decrease of arterial PCO2 and an increase of minute ventilation. The stimulating effect of S 2620 was maximal in the 10th min; after 60 min, ventilation and PCO2 approached control levels. The CO2 ventilatory response was determined 10 min after the administration of S 2620. The slope of the control and S 2620 stimulated curves was similar with a shift towards higher ventilation and lower PCO2 after S 2620 administration. Functional capacity rose with increasing minute ventilation. The increase of functional residual capacity disappeared after bilateral cervical vagotomy.

Almitrine↗
PubMed1983

The role of vagal nerves in changes of functional residual lung capacity during acute hypoxia.

Functional residual capacity of the lungs (FRC) was measured by a plethysmographic method in anaesthetized, intubated rats breathing air or a hypoxic mixture (10% O2 in N2), before and after bilateral cervical vagotomy. Inhalation of the with intact vagi, the drop in Pao2 was accompanied by a significant rise of FRC; after hypoxic mixture led to the same decrease in Pao2 before and after vagotomy. In rats vagotomy, hypoxia did not affect the FRC. The vagal nerves are thus apparently necessary for the increase of FRC during hypoxia in the rat.

Acute Disease↗
PubMed1981

Pulmonary hypertension induced by repeated pulmonary inflammation in the rat.

The effect of repeated lung inflammation on the pulmonary vascular bed was studied in rats. Nonbacterial lung inflammation was induced by repeated carrageenan instillations into the lungs. Three days after the single carrageenan injection, the mean pulmonary arterial blood pressure was only slightly raised [16.3 +/- 0.6 (mean +/- SE) Torr in controls and 19.5 +/- 0.5 Torr in rats with lung inflammation, P less than 0.001]. A substantial pulmonary hypertension was found in rats 3 days after the sixth lung inflammation (24.6 +/- 1 Torr). In this group, arterial hypoxemia, hypercapnia, and right-heart hypertrophy were found. In the 14th day of recovery after the last injection of carrageenan, the mean pulmonary artery blood pressure decreased (18.5 +/- 0.9 Torr) but remained higher than in the control group. There was no difference in cardiac output measured by dye-dilution technique between the experimental and control groups. After repeated inflammation, the media of distal pulmonary vessels thickened and the number of pulmonary arterioles with distinct media increased.

Animals↗
PubMed1979

Pulmonary hypertension in rats with papain emphysema.

Lung emphysema was produced in 80 rats by tracheal chronic constriction and repeated instillations of 0.1% papain solution intratracheally. 17 animals survived 90 days of the experiment; a complete examination was performed on 14 experimental and 11 control animals. 9 rats of the experimental group had pulmonary hypertension, in 5 other rats the pulmonary arterial blood pressure was not different from that in the controls. The experimental animals with hypertension had arterial hypoxemia and increased weight of the right ventricle. All experimental rats (with and without pulmonary hypertension) had increased air spaces in the lung and thickened media of distal pulmonary vessels. After breathing 100% oxygen for 20 min, the pulmonary arterial blood pressure in animals with pulmonary hypertension decreased but did not reach the control level. The decrease of the mean pulmonary arterial blood pressure after oxygen breathing correlated well with the initial level of pulmonary hypertension and with the degree of hypoxemia during air breathing.

Animals↗
PubMed1977

Effect of anaesthesia on the pattern of breathing.

The pattern of breathing of male rats was studied after stimulating respiration with carbon dioxide at different levels of general anaesthesia. Anaesthesia was induced by the inhalation of halothane or by the i.p. injection of urethane. Ventilation values were measured in intubated rats in body plethysmograph. It was found that a linear relationship between minute ventilation and tidal volume was maintained during the decrease of minute ventilation due to deepening of anaesthesia. The slope of the relationship after stimulating respiration with carbon dioxide also diminished during deeper anaesthesia. The duration of inspiration did not alter significantly, despite marked changes in tidal volume. Tidal volume correlated with the duration of expiration at different anaesthesia levels. In vagotomized rats, the duration of expiration shortened as ventilation was depressed by deepening anaesthesia.

Anesthesia, Inhalation↗