摘要:

AbstractA simple differential respirometer equipment for experimental work with tissue cultures of liver is described. The respirometer works with small amounts of tissue (0.3–3 mg dry weight). The respiration values obtained indicate that the employed cultivation technique permits gas exchange at a rate adequate for normal liver also when the working gas phase consists of ordinary ai

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05165.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractA plethysmography technique was utilized to investigate the reactions within consecutive vascular sections of the small intestine of the cat during and after a 2–3 h local arterial hypotension at approximately 55 or 30 mm Hg produced by graded arterial occlusion. The sympathetic nerves to the intestine were cut. The resistance vessels were dilated during hypotension, the dilatation being more pronounced the lower the perfusion pressure. In the early phase of hypotension this autoregulation of intestinal blood flow was probably mainly “myogenic” while it was predominantly “metabolic” in the late part of hypotension. When releasing the arterial occlusion, blood flow returned to control after a 55 mm Hg hypotension, while a marked prolonged vasodilatation was observed after the 30 mm Hg hypotension. The capillary filtration coefficient was not changed from control during a hypotension at 55 mm Hg while it was enhanced at 30 mm Hg. Mean capillary hydrostatic pressure seemed to increase in the latter half of most experiments performed at this level. An additional, transient augmentation of capillary pressure seemed to occur after the hypotension. Upon releasing the arterial clamp after a 30 mm Hg hypotension the whole cardiovascular system seemed to derange progressively to judge by a decline of arterial blood

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05166.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractSynchronized bursts of efferent sympathetic impulses, appearing either spontaneously or triggered by various peripheral stimuli, were recorded with microelectrodes inserted percutaneously into skin nerve fascicles in alert, adult subjects. The signals were abolished by sympathetic ganglion blocking agents and by Lidocaine nerve blocks proximal to the recording site. Many of the sympathetic discharges were succeeded by skin resistance changes and plethysmographic vasoconstrictor responses within the innervation zone of the fascicle impaled. The sympathetic activity was not pulse synchronous as in muscle nerves and the spontaneous sympathetic volleys occurred largely independently of spontaneous blood pressure variations, indicating a relative lack of baroreflex control of the vasoconstrictor outflow to the skin. A loose coupling was observed, however, between the resting respiratory rhythm and the spontaneous sympathetic bursts in the skin nerves.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05167.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractSympathetic activity was recorded from human skin nerves during the execution of a variety of different manoeuvres. The neural activity (composed of vasoconstrictor and sudomotor impulses) was regularly affected by emotional, thermal and respiratory stimuli. Mental stress, body cooling and increased respiratory movements all increased the sympathetic outflow, whereas the activity decreased during moderate body warming and when the. subject was calm and relaxed. Manoeuvres known to cause changes in baroreceptor activity usually did not affect the sympathetic outflow to the skin. When comparing neural and effector organ responses during the different manoeuvres the changes in sympathetic activity correlated well with changes in skin vascular resistance (either measured simultaneously or as reported in the literature). A comparison of the sympathetic responses recorded from human skin‐ and muscle nerves was also made. It was concluded that most manoeuvres had different effects in the two nerve types, thereby confirming earlier indirect evidence for selective regional control of the sympathetic outflo

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05168.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe experiments were performed on isolated, autoperfused subcutaneous tissue in urethane‐anesthetized female rabbits. Directly recorded blood from adipose tissue averaged 6.6 ml/100 g‐min (S. D. 4.2, 11 expts.). The blood flow calculated from the washout of Xenon‐133 with an average partition coefficient on 11.8 (ml/g) was 7.4 ml/100 g‐min (S. D. 5.3, 11 expts.). A direct proportionality was found between blood flow in adipose tissue calculated from the washout of Xenon‐133 and directly recorded blood flow. The coefficient of correlation was 0.995 (p<0.001). When blood flow was constant during the experiments, the washout curves were monoexponential. In the preparation used, the adipose tissue appears to have homogeneous distribution of blood flow and it is likely that diffusion equilibrium of the highly diffusible, inert gases exists between adipose tissue and blood during the washout. The discussion contains a survey of the recently found values of blood flow in adipose tissue obtained with different t

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05169.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractIn cats anesthetized with chloralose electrical afferent stimulation of the right cardiac nerve promptly elicited marked hypotension, bradycardia and relaxation of the stomach. Stimulation threshold and conduction velocity measurements indicated that the stimulated afferents were unmyelinated fibres. The circulatory and gastric responses were abolished by cervical vagal blockade on the stimulation side. Administration of nicotine intrapericardially or veratrum alkaloids i.v. produced similar circulatory and gastric responses as the electrical nerve stimulation. The effects of veratrum were markedly reduced upon application of a local anesthetic in the pericardial cavity. Reflex gastric relaxation was also elicited in response to occlusion of the ascending aorta or mechanical stimulation of the left ventricle. With occlusion of the pulmonary artery only slight gastric responses were obtained during the occlusion. Pronounced gastric responses were recorded upon occlusion of a coronary artery, the effect being abolished by section of the vagi in the neck. – It is concluded that marked reflex relaxation of the stomach can be elicited from heart receptors, probably located in the left ventricle and with unmyelinated afferents in the vagi. It is suggested that the described reflex gastric response may form part of a vomiting patter

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05170.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractSplenic blood flow was measured in normal guinea‐pigs of three weight classes, and in groups immunized with pertussis vaccine or sheep erythrocytes (SRBC). The determination was based on the wash‐out of xenon 133 injected directly into the splenic tissue.In the normal guinea‐pigs the blood flow in ml/g min decreased slightly with weight, the means in the three weight classes being 0.85, 0.73 and 0.66 ml/g min. After injection of pertussis vaccine the splenic blood flow was significantly greater in relation to the weight of splenic tissue than for the controls given a saline injection, but the flow was unaffected by immunization with sheep erythrocytes.Combination of the blood flow values with the differences in lymphocyte content between splenic efferent and afferent blood made it possible to calculate the splenic release into the blood of lymphocytes formed in the spleen. This increased with body weight, and in the heaviest animals reached about 10ocells/24 h. In the animals injected with pertussis vaccine the number of lymphocytes released was significantly greater than in the corresponding controls. An increase recorded after immunization with sheep erythrocytes was, however, not statistically signif

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05171.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractIsolated vas deferens preparations from rats aged 2–22 days were stimulated transmurally in a superfusion bath. The first responses to postganglionic nerve stimulation appeared in preparations from animals 3 days of age whereas responses to exogenous noradrenaline (NA) and direct stimulation of the smooth muscle cells were obtained one day earlier. Preparations of all ages responded readily to low concentrations of exogenous NA (0.2–5.0, μg/ml) while acetylcholine (ACh) had to be added in much higher concentrations (10–100, μg/ml) to give equal direct responses.a‐receptor blockers (phentolamine or phenoxybenzamine, 0.2–2.0, μg/ml) totally inhibited the contractions of preparations from animals up to about 10 days of age, but thereafter the effect was changed into potentiation of the responses. Atropine (0.5–2.0, μg/ml) generally caused a slight decrease of contractions of preparations up to about 15 days of age, but at later stages it was without effect.It is concluded that the major part of the motor innervation of the rat vas deferens is adrenergic but that subtreshold amounts of ACh probably are liberated from some source within the organ on transmural stimulation. The most probable explanation for the greater sensitivity of the young vas deferens preparations to the specific receptor blockers seem to be a greater accessibility of the junctional receptors, perhaps in combination with relatively smaller amounts of transmitter liberated at t

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05172.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractIsolated rat vas deferens preparations were intermittently field stimulated (30 s every min) for 2 or 4 h at 7 or 25 imp/s. At the low stimulation frequency only a very small reduction (7 %) of the endogenous noradrenaline (NA) stores was seen during 4 h stimulation while it was about 15%after 2 h and 37%after 4 h at 25 imp/s. Addition of drugs known to inhibit NA synthesis (a‐methyl‐p‐tyrosine, a‐MPT, 4times10‐4M) or uptake (cocaine, 10‐5M) did not apparently influence neither the spontaneous nor *the nerve‐induced reduction of the endogenous NA stores. The present results seem to support the hypothesis that the functional transmitter pool of the short adrenergic neurons of the vas deferens is very small, and that the residual NA reuptake and synthesis after pharmacological blockade, together with minute refilling from the large storage pools, are able to maintain transmitter homeostasis without significant changes of the total endogenous NA content of the

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05173.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe occurrence of prostaglandins (PG), prostaglandin precursor acids, prostaglandin synthetase and 15‐hydroxy prostaglandin dehydrogenase was studied in subcellular fractions isolated from homogenates of rabbit renal papilla by sucrose density gradient centrifugation. The investigated fractions were lipid droplets, supernatant, microsomes and mitochondria as verified by electron microscopy. Most of the prostaglandins was found to be prostaglandin E2and was present in the supernatant whereas the prostaglandin synthetase occurred most abundantly in the microsomal fraction.‐Nearly all of the recovered prostaglandins were formed during the preparation of the subcellular fractions. Arachidonic acid was the major esterified C20acid and had the highest relative concentrations in the supernatant, microsomes, and mitochondria, whereas the lipid droplets had lower concentrations. No detectable 15‐hydroxy prostaglandin dehydrogenase was present in the supernatant fraction of the papilla. The results indicate that in the rabbit renal papilla prostaglandin E2 is formed mainly from locally available arachidonate in membranes which sediment in the microsomal fraction and which may be derived from either cell membranes or membranes of the endoplasmic reticulum. After their formation the prostaglandins are probably released into the cytoplasm of the cells rather than being concentrated within specific subcellular particles and may leave the papilla without undergoing metabolic inactiv

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb05174.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY