摘要:

AbstractThe responses to rapid stretches applied just prior to or during potassium‐induced contractures were investigated using small bundles of muscle fibres. In submaximal contractures induced by 27 or 42 mM KCl (in choline‐Ringer's) the “resistance to stretch” (i.e., the extra tension recorded about 0.1 sec following the start of the stretch) and the tension developed without stretching followed different time courses. When stretched during the rise in tension the muscles always developed greater tensions than when the same stretch was applied before exposure to the elevated potassium. The “resistance to stretch” was small at the start of the contracture, it was maximal about halfway through the rise in tension and it declined slowly thereafter. By a proper selection of the amount of stretch and the instant of stretching it was possible to obtain tensions equal to or greater than the maximal tensions induced by isotonic KCl. In contractures induced by isotonic KCl the “resistance to stretch” was maximal near the start, it declined slowly during the rise of tension, and it declined rapidly during the fall in tension. These results suggest that the changes in elasticity (as indicated by the ‘resistance to stretch’) and the ability to develop tension resulted from two distinct processes and in potassium‐induced contractures they follow different time courses which can be

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04244.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractNyhus, L. M., M. J. Rheault and L. S. Semb.The effect of antral acidification on the intestinal phase of gastric secretion in the Heidenhain pouch dog. Acta physiol. scand. 1965.65. 11–19. — Five dogs were prepared with vagally denervated antral pouches and Heidenhain fundic pouches. As a stimulus for the intestinal phase of gastric secretion a test meal was given, consisting of 200 g strained beef liver. The acid response from the Heidenhain pouch was determined in each dog in half‐hour samples for 4 hrs after the meal. In each dog, the following experiments were carried out:I: Test meal, no perfusion of antrum 25 expts. in 5 dogsII: Test meal, perfusion of antrum with 0.9 % saline 25 expts. in 5 dogsIII: Test meal, perfusion of antrum with 0.1 N HCl 25 expts. in 5 dogsIV: No test meal, perfusion of antrum with 0.9 % saline 10 expts. in 4 dogsThere was a highly significant greater average acid response to the test meal when the antrum was perfused with saline (II) as compared to the response when the antrum was acidified (III) (p = 0.00004) or not perfused at all (I) (O = 0.008). There was, however, no significant difference in the average acid outputs of expts. I and III (p = 0.059) in 4 dogs, the fifth showed a greater output (p = 0.040) when thc antrum was acidified. When no test meal was fed to the dogs, and the antrum perfused with saline, there was a release of endogenous gastrin from the antrum, as indicated by a measureable secretion from the Heidenhain pouches.The results are discussed, and the conclusion is drawn that the results do not support the presence of an antral chalone, but seem to support the theory that antral acidification has an inhibitory effect on relea

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04245.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractBojesen. E. and P. P. Leyssac.The kidnty cortex slice technique as a model for sodium transport in vivo. A qualitative evaluation. Acta physiol. scand. 1965,65, 20–32. — Morphologically the tubules of slices incubated at 37°C present thrmselves as occluded with greatly swollen cells in contrast to the open ancl distended tubules with well‐defined and cubic cells in vivo. The cellular sodium and potassium concentrations of incubated slices differ markedly from the calculated intra‐cellular concentrations in the functioning cells, which were found to be: 4–15 μeqNa+/g cellular Water and 123–135 μeq K+/g cellular water. Efflux studies on slices incubated with radioactive sodium did not disclose any active component when flushed with Ringer solutions of different electrolyte composition and temperatures, or in the presence of metabolic inhibitors. At a sulfate concentration of 6 mM, at which concentration the volume of distribution was equal to that of sodium, the curves on the log. of efflux rates of the two species of ions were parallel during eluation of almost the entire amount.The results suggest that at least a major fraction of sodium in cortical slices is in diffusion equilibrium with the surrounding medium. The turnover rate of sodium in the remaining minor fraction of the sodium pool subjected to active transport must be of an order of magnitude comparable to the diffilsion rate of sodium in the thin slices and thereforc faster than the turnover rate of intracellular sodium of st

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04246.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractJervell, J.,The antagonistic effect of human plasma albumin on the insulin stimulated of glucose uptake of the isolated rat diaphragm. Acta physiol. scand. 1965,65, 33–44. — Albumin isolated by several different procedures antagonized the effect of insulin on the glucose uptake of the isolated rat hemidiaphragm. The antagonism was still present after the pH reducing effect of the albumins had been corrected. A decrease in pH was also found to have some insulin‐antagonistic effect. There was no correlation between the antagonistic effect and the free fatty acid content of the albumins, and adding palmitate to a nonantagonistic albumin did not increase its antagonistic activity. The antagonistic effect cannot he explained by the calcium and magnesium binding properties of the al

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04247.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractAnderson, B., C. C. Gale, B. Hökfelt and B. Larsson.Acute and chronic effects of preoptic lesions. Acta physiol. scand. 1965,65, 45–60. — The effects of preoptic and preoptic/hypothalamic lesions were studied in unanesthetized goats. A gradual destruction of the entire preoptic region (the “heat loss center”) was induced by proton irradiation in two animals. The lesions caused a permanently raised heat‐dissipation threshold, an impaired resistance to cold, a complete adipsia and a lack of thermal inhibition of food intake. A febrile response to pyrogen was obtained in spite of the destruction of the preoptic region. In contrast to the proton lesions a rapidly induced radio‐frequency (RF) coagulation was fatal if restricted to the preoptic region. It caused initial strong shivering and peripheral vasoconstriction, sympathico‐adrenomedullary and thyroid activation, severe hyperthermia, hyperglycemia, and death within 16 hours in three goats studied. An ability to respond to severe hyperthermia with polypnea remained in these goats. In two goats preoptic RF‐lesions were extended to involve most of the anterior hypothalamus. These animals survived an initial period of hyperthermia and sympathico‐adrenomedullary activation. One of them was studied for 8 months and showed similar disturbances of temperature regulation and alimentation as the proton irradiated goats. In one goat the RF lesions was extended further caudally to involve also the mid‐hypothalamic region. The immediate effects were virtual disappearance of urinary excretion of noradrenaline development of marked hypothermia, and consi

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04248.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractJ. E. Kihlström.Periodic variation in the amount of semen yielded at spontaneous ejaculations of the male rat. Acta physiol. scand. 1965.65, 61–64. — Male rats have been prevented from grooming the penis by means of a stiff girdle, and the spontaneously ejaculated semen has been collected. The amount of semen yielded varies rhythmically with a mean period of 4.4

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04249.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractKernell, D.The adaptation and the relation between discharge frequency and current strength of cat lumbosacral motoneurones stimulated by long‐lasting injected currents. Acta physiol. scand. 1965.65. 65–73. — Cat lumbosacral motoneurones were stimulated by steady currents injected through the tip of an intracellular micro‐electrode. The results strongly indicate that the majority of undamaged motoneurones are capable of responding to steady currents by long‐lasting and well maintained repetitive discharges. Such discharges from various motoneurones were studied with regard to the adaptation and the slope of the linear relation between discharge frequency and current strength (cf. Granit, Kernell and Shortess 1963a, b). Measurements were also made of the lowest current strength (in units of rheobase) which was needed for eliciting a steady repetitive discharge. None of these characteristics relating to repetitive firing were found to be correlated with the duration of afterhyperpolarization, the latter being measured by single spike discharges (generally antidromic). The results have been discussed also with reference to earlier findings concerning tonic and phasic repetitive firing of motoneurones stimulated by muscl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04250.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractKernell, D.High‐frequency repetitive firing of cat lumbosacral motoneurones stimulated by long‐lasting injected currents. Acta physiol. scand. 1965.65. 74–86. Repetitive discharges were initiated in motoneurones by steady currents injected through an intracellular micro‐electrode. At weaker currents, producing firing rates up to on the average 51 (30–84) imp/sec, the steady discharge frequency was approximately linearly related to current strength (cf. Granit, Kernell and Shortess 1963a). Several cells were capable of setting up steady discharges only within this so‐called “primary” range. In many other cells, steady repetitive firing was obtained even with stronger currents. There were in the latter two ranges of steady firing, the primary one referring to weak and a “secondary” referring to stronger stimulating currents, each approximately fitted by a separate straight line in the graphs relating impulse frequency to current strength. The straight line wich referred to steady firing within the secondary range had a 2–6 times steeper slope than the one characterizing the primary range. Motoneurones capable of maintained firing within the secondary range could reach steady firing rates of the order of 125 (88–195) imp/sec. The maximal impulse frequency within the primary range was about the same initially in the discharge as later on. The findings are discussed also with regard to the repetitive firing of reflexly

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04251.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractKernell, D.The limits of firing frequency in cat lumbosacral motoneurones possessing different time course of after hyperpolarization. Acta physiol. scand. 1965.65, 87–100. — Long‐lasting repetitive discharges were set up in cat lumbosacral motoneurones by steady currents injected through the tip of an intracellular micro‐electrode. The upper and lower limits of discharge frequency of the various motoneurones were significantly correlated with the time course of their afterhyperpolarization the latter being measured from single spike discharges (generally antidromic). From previous work it is known that the relation between discharge frequency and current strength (the “f‐I relation”) is linear over a certain range from the minimal firing rate and upwards (Granit, Kernell and Shortess 1963, Kernell 1965b). In the present paper it was shown that the maximal discharge frequency within this linear part of the f‐I relation was also significantly correlated with the time course of afterhyperpolarization. The findings are discussed with regard to problems of regulation of muscle tension by repetitive firing on the part of t

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04252.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractThose single units, in the cortex corresponding to foveal representation in the monkey, which responded reproducibly to restricted portions of the spectrum did so to blue, to green or to red (Andersen, Buchmann and Lennox‐Buchthal 1962). The combined spectral sensitivity curves of these units showed the blue‐sensitive units to have a sharp peak at 470 nm. The sensitivity of the red‐sensitive units was broader, 590 to 650 nm, with peak sensitivity at 630 nm at the highest criterion of threshold. The green‐sensitive units gave sparser responses and were more variable from trial to trial, sometimes responding in a vaguely opponent colour fashion to about 500 and 590 nm, and sometimes with peak sensitivity at about

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1965.tb04253.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY