摘要:

AbstractA close relation between the state of wakefulness, the electroencephalogram, and the respiration has been demonstrated(Bülow1963). In the present paper it was assumed that as opening and closing of the eyes influence the EEG and thus probably the state of wakefulness, the responsiveness of the respiratory center may likewise be influenced by the single act of closing the eyes. Seven subjects were studied in the steady state of rest breathing ambient air, 4–5 % CO2in air, or 11 % O2in nitrogen. In experimental periods of 4–5 minutes their pulmonary ventilation and alveolar Pco2were measured while they randomly were either reading a book, or were blindfolded. It was found that in all three conditions closing of the eyes resulted in a mean decrease of VEof 8 to 14 % with a concomitant increase of PACO2of about 1 mmHg. It is tentatively suggested that other and stronger central or peripheral stimuli impinging on the reticular formation of the brain may explain the changed sensitivity of the respiratory center towards the chemical stimuli in conditions like exercise, chronic hypoxia

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10355.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractSuccinate dehydrogenase (SDH) and cytochrome oxidase activities in the lateral vastus of the human quadriceps femoris muscle together with total body V́o2max were followed during an 8–10 week period of endurance training (n=13) and a successive 6 week period without training (n = 8). During the training period there was a gradual increase in both Vo. max and muscle oxidative enzyme activities, all being significantly different from the pre‐training levels after 3 weeks of training. After 8 weeks of training V́o2. max was 19%, vastus lateralis SDH 32%, and cytochrome oxidase activity 35% above the pre‐training levels respectively. 6 weeks post‐training V́o3max was still 16% above the pre‐training level, and not signifi‐ficantly different from the level at the end of training (p>0.2). In contrast vastus lateralis SDH activity had returned to the pre‐training level. Cytochrome oxidase activity had returned to the pre‐training level within two weeks post‐training. The significantly faster post‐training decline in skeletal muscle oxidative enzyme activities in contrast to that of the V́o2max indicates that an enhancement of the oxidative potential in skeletal muscle is not a necessity for a high V́o2max. Moreover, the fast return to the pre‐training level of both SDH and cytochrome oxidase activities indicate a high turnover rate of enzymes in the TCA cycle as wel

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10356.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractMeasurements of transcapillary exchange of high‐molecular dextrans, K+and THO in therete mirabileof the eel (Anguilla vulgarisL.) have been made under steady‐state conditions while varying the amounts of plasma proteins in the perfusates. When the perfusates contained 20% or less horse serum the permeabilities of D‐75 000. K. and THO increased significantly. The effect on the K+permeability was irreversible while that on D‐75 000 and THO was not. The permeability was unaffected when the perfusate contained 30% serum or more. Adding 1.3g/100 ml bovine albumin to the perfusate maintained the D‐75 000 and THO permeabilities unchanged while that of K˜ appeared to increase. At an albumin content of 0.33 g/100 ml the effect was similar to that produced by low serum perfusates. Our main conclusion is that lack of the albumin fraction of the plasma proteins reversibly increases the intercellular pore area and irreversibly changes the K permeability of the cel

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10357.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractAdult skeletal muscle hypertrophy induced by exercise has been thought to be exclusively related to an increase in cross‐section area of individual muscle fibers and not to an increase in the number of muscle fibers. Recent experiments using surgical intervention to cause muscle overload have induced an increase in fiber numbers; however, the muscle also exhibited pathological alterations. The purpose of this study was to determine if an exercise regimen also induced hyperplasia. Cats were trained to lift weights with their right forelimb to receive a food reward. After 19–46 weeks of training, the flexor carpi radialis muscle (FCR) was removed and prepared for histochemical examination. The total number of muscle fibers of the right exercised FCR increased significantly (19.3%) when compared with that of the unexercised left FCR (p<0.05). This increase was found to be due to muscle fiber splitt

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10358.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe enzyme activity, expressed as total activity and concentration, was found to be decreased in the cholinergic neurones of the glands after treatment with pilocarpine for 10 days. The secretion of saliva evoked by the parasympathomimetic drug is thought to have reduced the reflex stimulation of the glands via the cholinergic secretory nerves and thereby lowered the enzyme activity in the nerves.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10359.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effect of acetate, at concentrations normally found during ethanol combustion in intact animals and manin vivo, on the uptake and oxidation of β‐hydroxybutyrate by the perfused rat hind‐quarter was studied. The addition of acetate did not significantly affect the total uptake of β‐hydroxybutyrate, but caused a 40 % decrease in the oxidation of β‐hydroxybutyrate to CO2. The oxidation of14CO2‐hydroxybutyrate to14CO2accounted for about 10 % of the total oxygen consumption by the perfused muscle in the absence of acetate. In the presence of acetate this figure was reduced to about 5 %. The addition of β‐hydroxybutyrate did not significantly affect the metabolic fate of14C‐acetate. It is concluded that acetate is preferred as oxidative substrate to β‐hydroxybutyrate. The inhibited oxidation of β‐hydroxybutyrate by acetate did not affect the concentration ratio between β‐hydroxybutyrate and acetoacetate in the medium at the end of the perfusion, indicating that the ability of the muscle tissue to restore an increased redoxlevel, “exported” from the liver during ethanol combustion to extrahepatic tissue

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10360.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10361.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb10362.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY