摘要:

AbstractCapillary filtration coefficient (CFC), reflecting precapillary sphincter tone, and venous outflow of cat lower leg muscle were observed at various transmural pressures before and during muscle work. Increasing transmural pressure in resting muscle 30 mm Hg caused a 35 per cent decrease in CFC, indicating increased tone of precapillary sphincters and, on the average, no change in blood flow, indicating that the increased active tone of resistance vessels closely balanced passive distention. During exercise at 1 twitch/sec, elevating transmural pressure decreased CFC by 50 per cent and increased flow 38 per cent indicating that while precapillary sphincters were still responsive, metabolic demand caused the resistance vessels to behave passively. At 4 twitches/sec the active response of the precapillary sphincters was present, although less marked, whereas the passive behaviour of the resistance vessels was even more pronounced than at 1 twitch/sec. Myogenic autoregulation of filtration exchangeviaalteration of precapillary sphincter tone may be an important factor preventing gross edema in the legs of upright man during exercise.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03624.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractAscaris suiswas extracted with 60% ethanolin dilute formic acid after previous removal of fat with organic solvents. After dialysis, the extract was further purified by ammonium sulphate precipitation, treatment with Amberlite IRC‐50 (XE‐64), chromatography on CM‐ cellulose and gel filtration on Sephadex G‐25. The purified product with a molecular weight probably within the range 2000–3000, had basic character with an isoelectric pointca12.3 in 0.05 M borate buffer. It behaved as a nearly homogeneous compound on paper electrophoresis and on gel filtration. Nitrogen content: 16.7%. Fifteen amino acids were identified by paper chromatography after acid hydrolysis: alanine, arginine, cystine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine and valine. The purified product was degradrd and inactivated by the proteolytic enzymes papain, pronase, trypsin, α‐chymotrypsin and partially by pepsin. The polypeptide caused degranulation of rat mesentery mast cells, even such cells from germ free animals, indicating that the mast cell respome was the result of a direct action of theAscarisprinciple on the mast cell and not due to an antigen antib

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03625.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe accumulation of noradrenaline (NA) was determined biochemically after incubation with NA of slices from the vas deferens, cerebral cortex and neostriatum of rats pretreated with reserpine and nialamide. It was found that both areas rich in NA terminals, such as the vas deferens and cerebral cortex, and areas rich in dopamine (DA) terminals, such as the neostriatum, efficiently accumulated NA. (+)‐Amphetamine effectively inhibited NA accumulation in all the tissues, whereas desipramine inhibited the uptake in areas rich in NA terminals efficiently, but in areas rich in DA terminals only to a slight extent. In this respect, the effect of chlorpromazine was similar to that of desipramine. The data strongly support the view that the reserpine‐resistant accumulation mechanism of the transmitter differs in the two types of catecholamine termin

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03626.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractPlasma renin activity, clearance of inulin (Cin) and para‐aminohippuric acid (Cpah), urinary sodium and potassium excretion during supine exercise were studied in normal healthy men. 8 subjects were treated during exercise with dihydralazine (Nepresolin® i.v.) and 8 subjects were untreated (control group). In the untreated subjects there was a statistically significant decrease in Cpahand increase in filtration fraction. The decrease in Cparduring exercise was less in the dihydralazine‐treated group and the increase in filtration fraction almost inhibited. Urinary sodium excretion decreased significantly in both groups during exercise but returned slowly to pre‐exercise level in the dihydralazine group. Plasma renin activity increased during exercise in both groups, most markedly in the dihydralazine group. After exercise plasma renin activity decreased to pre‐exercise level in the control group but continued to increase in the dihydralazine group in spite of the increased renal blood flow. The findings indicate more marked sympathetic activity in the dihydralazine group and it is suggested that the sympathetic nervous system may have a direct influence on renin release irrespective of its renal hemodynami

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03627.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe effect of ganglionic blocking on piasma renin activity and plasma sodium concentration during exercise and pain stress were studied in rats. 20 female albino rats were exercised by swimming and 16 received intramuscular injections of 1 ml 10% NaCl. Half of the animals in each group were pretreated with a ganglionic blocking drug (Ansolysen®). In both groups there was a significantly lower plasma renin activity in the ganglion‐blocked animals compared with their untreated controls, which indicates the importance of the sympathetic system for renin release. The findings suggest that changes in plasma sodium concentration are of minor importance compared with sympathetic activi

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03628.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractLundberg presented the hypothesis that the secretory potentials in salivary glands were due to an active transport of chloride ions. This transport should be responsible for the formation of the saliva. Recently a different hypothesis has been proposed by Imai, who postulated that the secretory potentials were caused by an increased permeability of the cell membranes to potassium ions. The present investigation was undertaken to test Imai's hypothesis. It was found that the secretory potentials and the secretory rate depended in very much the same way on the extracellular potassium concentration. This gives further support to Lundberg's hypothesis.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03629.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractTechniques are described for recording directly the contractile responses elicited in the longitudinal smooth muscle of cat or rabbit portal vein by vasomotor nerve stimulation in situ or in vitro. This vascular smooth muscle, which shows a spontaneous rhythmic activity of 3 to 8 contractions per minute, responded to splanchnic or postganglionic nerve stimulation by an increase in the mean level of tension associated with an increased frequency of contractions. Guanethidine abolished these neurogenic responses indicating that they were due to adrenergic sympathetic fibre activation. Effects of vagal nerve stimulation were weak and inconsistent. The quantitative tension responses produced by splanchnic or postganglionic nerve stimulation at graded impulse rates increased steeply in the low frequency range and reached a maximum at 8 to 16 imp/sec. These frequency‐response curves, obtained by direct recording of vascular smooth muscle contractions, are in conformity with those found in previous investigations studying blood flow or regional blood volume in intact vascular beds. The mechanisms by which the sympathetic innervation controls activity in rhythmically active vascular smooth muscle and the quantitative aspects of this influence are discussed in the light of the present resul

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03630.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe longitudinal musculature of the rat portal vein is characterized by spontancous, rhythmic contractions indicating effective intercellular conduction in this vascular smooth muscle. The present study was done in order to evaluate the relative importance of neurogenic and myogrnic mechanisms for the spread of excitation in an isolated preparation of this vessel. A local anesthetic agent, in concentrations which blocked impulse transmission in autonomic nerves, failed to interfere with conduction in the smooth muscle of the portal vein whereas hyperosmolarity. which is considered to preclude electro tonic spread of action potentials between muscle cells (Barr. Dewey and Rerger 1965), caused desynchronization of the contractile activity. It is concluded that conduction in this vascular smooth muscle is myogenic in nature. The fact that the portal vein, in contrast to most other vessels, is equipped with a “double plexus” of adrenergic nerve fibres (Fuxe. personal communication) does not seem to be important for coordination of its spontaneous contractions. The influence of the hyperosmotic environment on the electrical and mechanical activity of the portal vein is illustrated by experiments with a sucrose‐gap technique. The mode of action of hyperosmotic solutions is disc

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03631.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe effect of arterially injected adrenaline and noradrenaline on lung blood volume has been examined in isolated, blood‐perfused lung preparations from rabbit and cat. Both substances caused rapid and relatively marked reductions in the weight of the preparations, which was followed continuously. This weight reduction is interpreted as being due to constriction of capacitance vessels. This effect on the capacitance vessels was mediated via α‐receptors, as addition of the α‐inhibitor phentolamine abolished the response. Addition of the β‐inhibitor propranolol did not interfere with the effect of the catecholamines on the capacitance vessels. Noradrenaline usually gave an increase, adrenaline usually a decrease in pulmonary vascular resistance in this preparation. The effect of the catecholamines on capacitance vessels was dissociated from the effects of these drugs on the vascular resistance in

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03632.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractBlood prrssure, heart rate, blood flow to the hind limb and behaviour wcrv studied in conscious dogs during topical stimulation of the sympathetic vasodilator outflow area in the hypothalamus and the mesencephalon. The responses obtained on stimulation were: a rise in blood pressure, tachycardia and also an increasr in hind limb blood flow which could bc abolished by atropinc. The effects on circulation caused by stimulation were essentially the same in the conscious and the anaesthetized dog. The behavioural changes on stimulation were relatively small and consisted of variations in the degree of alertness. In many experiments marked circulatory responscs were obtained on stimulation without any apparent behavioural reactions. Whether these findings indicate that the cholinergic vasodilator system acts more generally in circulatory homeostabis or is restricted to participation in specific situations ase.g. adjustments preparatory to niuacle effort. is discussed.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1967.tb03633.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY