Acta physiologica Academiae Scientiarum Hungaricae最新文献

A high proportion of the "intermediate" muscle fibres, which are semi-dark after both acidic and alkaline preincubation in ATP-ase staining, was found in the thigh with heart failure. Characteristic patterns of fibre splitting were found mostly in jumpers' muscles. Possibilities of fibre subgroup transformation and fibre hyperplasia due to training are discussed.

The effects of Zn2+, Mg2+ and Mn2+ in vitro were studied on the procoagulant activity of peritoneal PMN leukocytes derived from endotoxin treated rabbits. The cells collected from the abdominal cavity were incubated in the presence of these divalent cations at 37 degrees in Hank's solution followed by determination of the clotting activity of their supernatants in citrate treated rabbit plasma. When the cells were incubated in the presence of 50 microM/l ZnCl2 the procoagulant activity of their supernatants decreased by 30%. Upon the application of 100 microM/l ZnCl2 a 50-60% increase in clotting time was observed. Zinc ions inhibited in a concentration dependent manner the release of procoagulant material from leukocytes. Neither of the other cations used as controls has influenced clotting time if assayed in a similar system. It has been established that zinc ions inhibited the liberation of tissue factor from endotoxin treated PMN leukocytes. The inhibitory effect was dose dependent and increased from 5 microM/l to 250 microM/l exponentially. The inhibitory effect of zinc ions on tissue factor liberation might be explained by membrane stabilization.

Blood was collected from the right ovarian vein on every third day of pregnancy in rats and the ovarian venous outflow and haematocrit were measured. Progesterone and 17 beta-oestradiol were determined by RIA from the ovarian venous and peripheral blood and the secretion rate of progesterone (ng/min) and 17 beta-oestradiol (pg/min) was calculated. An elevated level of ovarian venous blood flow was found on day 9 and 12 of pregnancy when the progesterone secretion reached the highest values. Blood flow began to decrease on day 15, the progesterone secretion rate on day 18. On day 21, progesterone secretion rate returned to the day-1 level, however, at this time the progesterone concentration of ovarian venous blood and peripheral blood remained significantly elevated. Secretion rate of 17 beta-oestradiol showed a gradually tendency to increase from day 12 reaching the highest value on day 21. Ovarian and peripheral venous blood level of 17 beta-oestradiol increased parallelly from day 15. The high level of ovarian blood flow and progesterone secretion in mid-pregnancy is suggested to be the result of the stimulation of luteotropic material originating from the placenta. Since the ovarian venous blood flow changes during pregnancy, the hormone concentration of ovarian venous blood is not a reliable indicator of hormone production.

Proximal transtubular potential difference (PD) was measured using the semi-microelectrode technique in control (C, n = 10) and unilaterally denervated (D, n = 10) rats. Acute renal sympathectomy resulted in a twofold and fourfold increase in diuresis and sodium excretion, respectively, with no change in GFR. PD (mean +/- S.E.M.) in the earliest accessible proximal convolutions (EPT) of group C was +/- 0.27 +/- 0.08 mV (n = 16), while in group D it was -0.16 +/- 0.07 mV (n = 18) (p less than 0.01). PD in mid (MPT) and late (LPT) proximal segments was unchanged by denervation (MPT: C = 0.94 +/- 0.05, n = 21; D = 0.98 +/- 0.04, n = ns. LPT: C = 1.04 +/- 0.11, n = 17; D = 0.95 +/- 0.06, n = 18 NS.). The shift to the negative of PD in EPT caused by denervation lends support to our earlier suggestion that active transport of solutes and organic substances is depressed by sympathectomy in the proximal tubule. The unaltered PD in MPT and LPT seems to indicate that passive forces promoting reabsorption in this part of the nephron are probably preserved.

Chloroquine and mepacrine appear in the stomach wall and inhibit gastric emptying in the rat after oral or parenteral administration. Measuring their concentration in the stomach wall, it was found that it depended upon on the route of application. A smaller proportion of a given dose accumulated in the stomach wall when chloroquine and mepacrine were introduced by avoiding the stomach. The side effect of the two drugs, the inhibition of gastric motility, could be minimized by not only parenteral but also duodenal administration; the latter could be realized by enteric-coated tablets.

Involvement of the cells of pedal ganglia in the regulation of heart activity and their connections with visceral neurons was studied in the central nervous system of Helix pomatia L. It was found that (1) numerous cells of pedal ganglia receive inputs from the heart. The reaction of the pedal cells to heart afferents was characteristic: initial high frequency increase of firing followed by inhibition, then a secondary tonic increase occurred in activity. Some of the pedal cells were activated after a brief delay; (2) many of the cells of the visceral and right parietal ganglia were activated simultaneously with pedal neurons during tactile stimulation of the heart. In different ganglia the answer to heart afferents can be observed to the same or opposite directions but its duration was identical in every cell; (3) one cell of the left pedal ganglion (LP3) formed monosynaptic connections with several cells of the visceral ganglion. The axons of the visceral cells, connected monosynaptically to the neurons LP3, runs into the intestinal nerve. LP3 caused EPSPs on the visceral cells; (4) the heart excitatory motoneuron V41, simultaneously with a number of pedal cells, receives excitatory inputs from the heart. The heart excitatory motoneuron is involved in the afferent and efferent pathways of heart regulatory network; (5) a motoneuron (V43) was identified to cause relaxation of the heart, giving branches into the intestinal nerve and similarly to other motoneurons activated by heart afferents.

In an isolated spiral muscle preparation from the common bile duct of the dog and rabbit contraction was elicited by PGF2 alpha, in a concentration dependent manner. The contraction was long-lasting and reversible. As opposed to PGF2 alpha, morphine, noradrenaline and barium chloride did not induce a contractile response.

Male rats were trained to swim for 9-10 days to assess the effect of chronic stress on the capacity and affinity of specific glucocorticoid binding in the cytosol fraction of myocardial tissue. A significant decrease in the binding capacity for corticosterone (Cpd B) was found 24 hours after the last swimming test, while the affinity constant remained unchanged. Contrary to Cpd B binding, there was no change in the capacity of dexamethasone binding, and there was no decrease in the Cpd B binding capacity in rats which had been adrenalectomized 2 days prior to the training period. We conclude that daily swimming for 9-10 days alters the numbers of cytoplasmic Cpd B binding sites in the face of increased adrenocortical activity, while not affecting dexamethasone binding in the cytosol fraction of myocardial tissue.