摘要:

AbstractIn the isolated guinea‐pig gallbladder, contractions were induced by acetylcholine (ACh), the C‐terminal octapeptide of cholecystokinin (C8‐CCK), prostaglandin E2(PGE2), and the prostaglandin precursor arachidonic acid (ARA). The effects on these contractions induced by the inhibitor of the prostaglandin synthesis indomethacin, and of the prostaglandin antagonists polyphloretin phosphate (PPP), and SC 19220 were investigated. In a concentration of 0.5 μg/ml indomethacin inhibited the response to ARA but did not appreciably affect the contractions produced by ACh, C8‐CCK and PGE2. Indomethacin, 10 μg/ml, reduced the responses to all the agonists probably due to a non‐specific depressive effect. PPP, 1–10 μg/ml, had no effects on the contractions elicited by ACh, C8‐CCK and PGE2. In concentrations of 100–400 μg/ml, PPP caused a transient contraction in the gallbladder strips and reduced the responses to the agonists used. SC 19220, 2 and 8 μg/ml, selectively inhibited the responses to ARA and PGE2, leaving the contractions of ACh and C8‐CCK virtually unaffected. The inhibition of the response to PGE2was surmountable by increasing the bath concentration of the prostaglandin 5–100 times.—It is concluded that local synthesis and release of prostaglandins play no essential role for the mediation of the contractile effect of C8‐C

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05633.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractRats trained by repeated swimming bouts were compared with rats swimming once and with sedentary controls. Training caused a decrease in body weight, body triglyceride and fat cell size. Fasting plasma insulin was also decreased. However, plasma free fatty acids and glycerol were not changed. Incorporation of labelled glucose into fat cell triglycerides was decreased by physical training, which also caused a disappearance in the fat cell size dependence of adipose tissue glucose metabolism. The response to insulin of this pathway in enlarged fat cells was increased by physical training. After a single exhaustive swim the cell size dependence of triglyceride labelling of adipose tissue apparently also disappeared. It was suggested that physical training leads to an adaptation of adipose tissue metabolism with an increased insulin sensitivity. This effect as well as the disappearance of the cell size dependence of adipose tissue metabolism might hypothetically be due to a diminished glucose flow to adipose tissue caused by exercise.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05634.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe intestinal vasodilator responses evoked by close i.a. administration of cholecystokinin (CCK) and secretin, mechanical stimulation of the mucosa and transmural electrical field stimulation were abolished by the 5‐hydroxytryptamine (5‐HT) antagonist dihydroergotamine, given in doses sufficient to block the vascular effects of i.a. injected 5‐HT. Corresponding results were obtained by making the cat small intestine tachyphylactic to 5‐HT. Nervous blockade (tetrodotoxin), inhibiting the intestinal blood flow increase after mechanical mucosal or electrical field stimulation, left the vascular responses to exogenous CCK and secretin unaffected. An increased 5‐HT content in venous blood from the intestine was demonstrated during vasodilatations caused by electrical field stimulation. A participation of intestinal 5‐HT, possibly as a transmitter substance, in the vasodilator mechanism evoked by mechanical mucosal stimulation or electrical transmural field stimulation i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05635.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractSpontaneously hypertensive rats (SHR), aged 7 months (‘manifest’ hypertension) or 10–11 weeks (‘prehypertensive’), and renal hypertensive rats (RHR; ‘nonhereditary’ hypertension were compared with normotensive rats (NCR) concerning cardiovascular responses to mental ‘stress’. Blood pressure and heart rate were followed in pairs of awake SHR—NCR and RHR—NCR, while defence reactions were provoked by alerting stimuli (light, noise, vibrations). The tachycardia, here involving both accentuated sympathetic and centrally suppressed vagal discharge, reflected the intensity of neural activation and the pressuie rise the imposed load on heart and vessels. In both respects the SHR groups responded decidedly stronger than NCR and RHR, also after either adrenergic or vagal cardiac blockade. Since SHR and NCR hearts responded equally to graded vagal stimulations or to isoprenaline, the enhanced tachycardia responses reflected a truly intensified defence reaction in SHR. Further, SHR responded more often to mild stimuli than NCR, suggesting a lower ‘threshold’ for defence reactions, and more frequently with clearcut defence reactions than NCR which exhibited vagal bradycardia responses in 30 %,versus5 % in SHR. This hyperreactivity and apparent prevalence concerning ‘sympathotonic’ patterns in SHR during alertness, in turn tending to trigger structural vascular adaptation and manifest hypertension, is evidently genetically linked and not secondary to hypertension, being observed particularly in ‘preh

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05636.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe diurnal variation in the immunoassayable TSH content of sera of female and male adult rats under conditions of 12 hours' light and 12 h darkness was determined. In the females the TSH level rose gradually from 11 p.m. to 3 p.m. and then declined, in the males the level rose from 7 p.m. to 11 a.m. and then declined. Scattering of individual values was great (mean coefficient of variation was 0.45–0.46). For the estimation of the serum TSH level these determinants should be know

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05637.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractLongitudinal spread of induced activity was analysed in the rat portal vein and rabbit aorta and compared to propagation in the brachial, radial, ear, mesenteric, femoral and posterior tibial arteries of the rabbit. Isometric force in spiral strips or intact preparations was measured during superfusion with Krebs' solution. The lower 20 per cent of the preparation could be selectively exposed to exogenous noradrenaline (NA) or to transmural field stimulation. Propagation was inferred to occur when the amplitude of the local response, relative to that when the entire preparation was stimulated, exceeded the relative length of the locally stimulated tissue. No propagation was found in the rabbit aortic strip. Propagation was less in proximal than in distal muscular arteries. The calculated distance of propagation was greatest in the rat portal vein. The intact limb vessel preparations reponded to NA with phasic contractions. In the ear artery, here was propagation only of the first phase of this biphasic response. These results show that different sections of the rabbit vascular tree display individuality in their ability to support propagation. In general, propagation in the arterial tree appears to be greatest in the smaller vessels.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05638.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractIntravenous administration of the neurotoxin (taipoxin) to mice caused after a latent period death by respiratory paralysis. The length of the latent period varied with dose, the dose‐response relation being bilogarithmic. Taipoxin failed to affect the resting membrane potential and the action potential of muscle. It caused a slight reduction in the acetylcholine sensitivity of the muscle membrane. The main effect of taipoxin on neuromuscular transmission was to reduce spontaneous and evoked transmitter release. The frequency of spontaneous miniature end‐plate potentials (m.e.p.p.s) was reduced to complete stop and depolarization of nerve terminals by a high potassium concentration (20 mM) failed to cause a marked and sustained increase in m.e.p.p. frequency. With nerve stimulation the amplitude of end‐plate potentials (e.p.p.s.) was reduced and with repetitive stimulation the amplitude of e.p.p.s. rapidly fell to a low level. Post‐tetanic facilitation of m.e.p.p. frequency and of e.p.p. amplitude were absent. The shape of evoked e.p.p.s. indicated asynchronous release of transmitter quanta. The effects of the toxin on neuromuscular transmission progressed even when the muscle was removed from the animal and placed in toxin‐free bathing fluid. Invitroexperiments showed that the rate of onset of neuromuscular block depended on the temperature of the bathing solution and on the degree of activity at the neuromuscular junction. Thus, incubation in toxin solution during 4 hr at 28° C failed to produce a neuromuscular block while at 37° C the block was complete within 1 h. With nerve stimulation at 10 Hz for 2 s every 2 min the rate of blockade was more rapid than in unstimulated preparations, similarly 20 mM potassium in the bathing fluid enhanced the rate

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05639.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractPlateau values of deep body temperature were diminished during work after intake of 1 1/2 1 water, they were increased after intake of 2–3 % sodium chloride solution and after dehydration in a sauna by 1 1/2 kg. The shifts in plateau values were related to plasma osmolarity, not to plasma volume. In rest and during work at low temperature (7° C), when there was virtually no sweating, the effect of plasma osmolarity on body temperature disappeared. The rate of increase in sweating at the start of work was faster than normal after intake of water and slower after intake of sodium chloride solution and dehydration. The mechanism by which the changes in temperature were brought about is the increase in sweating at the start of work. Plasma osmolartiy may cause these changes either by a peripheral effect on the sweat glands or a central effect on the thermoregulatory centr

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05640.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractIt has been found that previous heavy or long‐lasting exercise results in a diminished ability to raise the blood lactate concentration by exhaustive supermaximal work (Hedman 1957, Astrandet al. 1963, and others). No definitive explanation for this phenomenon has been given. It was the purpose of the present experiments to throw light on the question whether a diminishing store of carbohydrates in the body could be the cause for the declining ability to liberate energy anaerobically by breakdown of glycogen to lactic acid. In 3 subjects the stores of glycogen were presumed to be varied 1) by repeated bouts of supermaximal and submaximal exercise on the bicycle‐ergometer, and 2) by diet after previously depleting the carbohydrate stores by exercise. It was found that in all cases the ability to work anaerobically and to produce lactate decreased with decreasing amounts of available carbohydrate. Disturbances in water or electrolyte balance were avoided. It is tentatively suggested that the velocity of the enzymatic process glycogen—glucose‐1‐phosphate is the limiting factor, and that this process is slowed down by lactic acid accumulation, the more the lower the substrate (glycogen) concentration is. Glucose, which enters the glycogenolytic chain as glucose‐6‐phosphate, can partly restore the ability for lacta

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05641.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractRat skeletal muscle was analysed at different ages, from birth to 90 days, for its concentration of phospholipids and individual phosphoglycerides, and for the fatty acid pattern of cardiolipin, choline phosphoglyceride (CPG), ethanolamine phosphoglyceride (EPG), inositol phospho‐glyceride and serine phosphoglyceride (SPG). The concentration of phospholipids was found to increase between birth and two weeks of age, after which it decreased slightly to 14 μmol/g fresh weight at the age of 90 days. The relative amount of CPG and EPG varied but little with age, while that of cardiolipin increased to three times its original value. The concentration of polyenoic acids increased with age in all phosphoglycerides except SPG. The concentration of the sum of the fatty acids of the linoleic acid series in CPG increased rapidly during the first weeks of life, while that of the linolenic acid series increased throughout the period studied. In EPG the concentration of the sum of the fatty acids of the linolenic acid series increased, while that of the linoleic acids decreased and the concentration of linoleic acid in cardiolipin increased. In the muscles of 90‐day‐old rats, the fatty acid pattern of cardiolipin showed a high level of linoleic acid and no fatty acids of the linolenic acid series. The fatty acid pattern of CPG was characterized by rather high levels of both linoleic and arachidonic acids and that of EPG by a high concentration of the fatty acids of the linolenic acid

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05642.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY