摘要:

AbstractBefore, and after 22 weeks of physical training, oxygen uptake, heart rate and cardiac output (dye dilution technique) were measured in 7 male subjects (22 to 26 years old) during pro longed severe exercise (60 min on 75%of the individual's maximal oxygen uptake) and during exhausting work loads of about 5 min duration. Maximal oxygen uptake increased from 3.41 l/min (48.0 mllkg per min) before to 3.64 I/min (52.0 ml/kg per min) after the training (p<0.05). Maximal heart rate decreased from 201 beats/min before to 194 beats/min after the training (p<0.05). During the 1 hr work period after the training the stroke volume and mean blood pressure became higher (p<0.05) and (a—v)O2diff. lower (p<0.05) than before the training. From the 5th to the 60th min of the prolonged work the heart rate increased about 20 beatslmin before as well as after the trainin

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04650.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe acetylcholine content of the bull retractor penis muscle, duodenum and urinary bladder was assayed By super fusion of the eserinized frog rectos muscle. The capacity of retractor homogenates to split acetyl‐β‐methylcholine, butyrylcholine and acetylcholine was estimated with the manometric technique. The acetylcholine content of the retractor was of the same order of magnitude as that of the duodenum, but it was twice as high as the amount found in the urinary bladder. A moderate activity of acetylcholinesterase and non‐specific cholin esterase was observed. The role of acetylcholine in the function of the efferent nerve fibres running in the bull retractor is discussed. So far as the classical definitions are applied it is regarded as unlikely that it serves as a neurohumoral transmitter substance either at ganglionic synapses or at neuro effector junctions. There is as yet no conclusive explanation for the mode of action of acetylcholine in these nerve

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04651.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe catechol‐O‐methyl transferase activity in the retractor penis muscle, liver, and kidney of the bull was determined by measuring the amount of metanephrine formed from adrenaline when S‐adenosylmethionine was used as methyl donor. The monoamine oxidase activity in the same tissues was estimated By measuring the rate of disappearance of 5‐hydroxytryptamine added to the incubation mixture. There was a very low, if any, catechol‐O‐methyl transferase activity in the retractor muscle, a slight but distinct activity in the kidney, and a high one in the liver. The monoamine oxidase activity exhibited By the retractor muscle was moderate. In the liver the activity of this enzyme was high but it was still clearly exceeded by that in the kidney. The role of both enzymes in the function of the retractor muscle is briefl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04652.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe influence of systolic left ventricular pressure (SLVP) and maxjmum rate of rise of left ventri cular pressure (dP/dt) on left myocardial oxygen consumption (MVO2) has been studied in intact, anesthetized dogs. Noradrenaline and angiotensin were infused in animals which had been bled to a mean aortic blood pressure of 50–60 mm Hg. End‐diastolic volume was reduced by bleecling, but remained fairly constant during the pressure changes caused by the noradrenaline and angio tensin infusions. Wall tension could therefore be regarded as proportional to SLVP.During noradrenaline infusions, which were adjusted so as to increase mean aortic blood pressure to 130 mm Hg, SLVP, dP/dt and MVO2increased. An unchanged relationship remained between dP/dt and MVO2after a‐adrenergic receptor blockade when SLVP did not rise. During infusion of angiotensin there was a marked elevation of SLVP, but only small increases in MVO2and dP/dt.On the basis of the changes in MVO2, SLVP and dP/dt, it was shown that the contribution to an increase in MVO, of a rise in SLVP is accounted for By the concomitant increase in

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04653.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effects of afferent stimulation of renal nerves on efferent sympathetic activity and systemic blood pressure were studied in anesthetized rabbits. In most animals, afferent impulses pro duced reduction or abolition of sympathetic activity and a fall in blood pressure. High fre quencies of stimulation (20–30 pulses/sec or more) caused a more marked and long‐lasting depression of efferent activity and blood pressure than low frequencies. The highest sensitivity of blood pressure to variations in stimulation frequency was found in the range of 1–10 pulseslsec. Stimulation of the renal afferents had qualitatively the same effect on sympathetic activity and blood pressure as aortic nerve stimulation, but for the aortic nerve, higher stimu lation frequencies were required to obtain the same reduction in blood pressure. It is con cluded that afferent activity in renal nerves has a predominantly inhibitory effect on vasomotor activity, resulting in a fall in blood pre

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04654.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effect of in vivo hemorrhagic shock and its treatment with hypothermia was studied by following the temporal pattern of intracellular potassium content in single skeletal muscle fibres during in vitro incubation. For the control cells isolated before the different experi mental procedures were instituted, reproducible changes in potassium content were observed during the period of incubation. The potassium content of cells isolated shortly after the taking of the biopsy was somewhat lower than of cells isolated after 10 min of incubation. After 10 to 15 min of incubation a marked loss of cellular potassium was seen, followed by a period of active reaccumulation. After hemorrhagic shock under normothermal conditions the potassium content of the cells was markedly lower and no active cellular potassium reaccumulation was obtained during prolonged incubation. Hemorrhagic shock treated with hypothermia lowered the initial pptassium content somewhat but both the periods of cellular potassium loss and active reaceumulation were seen. Hypothermia alone only slightly modified potassium transport during the first 10 to 15 min of in vitro incubation.The results are discussed from the standpoint of cellular metabolism and high‐energy phosphate production with special reference to the exchange of substances between body com partments under the diffrent experimental condition

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04655.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractSingle skeletal muscle cells were isolated after varying intervals of in vitro incubation at 20–22°C from a muscle biopsy of the adductor muscle of dogs. From each isolated fibre 3–4 pieces, 70–90 μ long, were cut out and analyzed separately. Dry mass was calculated from x‐ray absorption measurements. The potassium content was determined from x‐ray fluorescence microanalysis and from ultra‐micro flame photometric analysis.During the first 30–40 rnin of in vitro incubation profound changes in cellular potassium content took place. Cells isolated during the first few min of incubation usually had a lower potassium content than cells isolated after 5 to 10 min. In the period 10 to 25 rnin after the initiation of incubation the cells started to loose intracellular potassium. This cellular potas sium loss was followed by a period of reaccumulation, since cells isolated 30 to 45 rnin after initiating incubation usually had a potassium content as high as that of cells isolated after 5 to 10 rnin of incubation. When the sodium pump was inhibited by addition of 10‐3M ouabain to the incubation medium or if glycolysis was inhibited by 10‐3M monoiodoacetate, no reaccumulation of intracellular potassium was seen. 10‐3M 2.4‐clinitrophenol produced a pro found rapid loss of cellular potassium. It therefore appears that the reaccumulation of cellular potassium after the period of cellular potassium loss was dependent on the integrity of the sodium pump and a source of energy. The possible basis for the profund cellular electrolyte changes which occur during in vitro i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04656.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractStudies on the vascular smooth muscle responses to histamine and 5‐hydroxytryptamine and on the distribution of these amines in different tissues were performed in several species of reptiles. The responses to adrenaline, noradrenaline and acetylcholine were studied for comparison. Vascular actions were recorded bothin vivoas changes in systemic arterial blood pressure andin vitroas changes in vascular resistance in perfused preparations. The specificity of the action of each drug was evaluated by means of pharmacological blocking agents. Tissue levels of histamine and 5‐hydroxytryptamine were determined spectrofluorometrically. Fluorescence microscopy was used for histochemical localization of the histamine stores. The results indicate that histamine and 5‐hydroxytryptamine exert dual actions (inhibitory and stimulatory) on reptilian vascular smooth muscles which have thus acquired response patterns towards these amines similar to those found in mammals. Inhibitory as well as stimulatory actions of adrena line, noradrenaline and acetylcholine are also present in reptiles. Levels of 5‐hydroxytrypt amine are apparently low in most tissues, whereas many species show very high tissue levels of histamine. Histamine, except that of the stomach, is mainly located in tissue mast cells and blood basophils. Nutritional‐dependent variations in mast cell number are parallelled by varia tions in tissue histamine content. By comparing the present results with those previously ob tained in jawless vertebrates, fish and amphibians, a general outline of the evolution of vascular actions and tissue stores of histamine and 5‐hydroxytryptamine i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04657.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe C‐terminal octapeptide of cholecystokinin shares the pharmacological properties of the original molecule. Both seem to act directly on the smooth muscle cell of the gall‐bladder but indirectly via a nervous pathway in the ileum. Both reduce the resistance of the choledocho‐duodenal junction. This pharmacological profile is characteristic for a group of substances which besides cholecystokinin and its C‐terminal octapeptide also includes gastrin, pentagastrin and caerulein. There is a close chemical relationship between these substances,e.g. they all have the same C‐terminal tetrapeptide.Effective doses for the octapeptide were 0.1–0.5 ng/ml invitro. Its molar activity in the gall‐bladder and ileum is comparable to that of caerulein and about 3 times that of cholecysto kinin and 1000 times that of pentagastrin.Besides the heterologous caerulein the C‐terminal octapeptide of cholecystokinin appears as the most active gall‐bladder contracting agent known at present, with a molar activity about 100 times that of acetylcholine, histam

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04658.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe metabolism of nicotine and cotinine by a 10,000 ×gsupernatant fraction of mouse liver homogenate has been studied by using14C‐labelled compounds. The metabolism of nicotine was found to be TPNH and O2dependent and chromatographical evidences for the formation of cotinine, γ‐(3‐pyridy 1)‐γ‐oxo‐N‐methylbutyramide and hydroxycotinine are presented. Three unidentified metabolites and14CO2were also observed. The observed metabolites were also excreted in urine after intraperitoneal administration of nicotine. Chromatographical evidences revealed that cotinine is metabolized to hydroxycotinine, γ‐(3‐pyridyl)‐γ‐oxo‐N‐methylbutyr‐amide and/or demethylcotinine and one unidentified metabolite.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04659.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY