摘要:

AbstractAn animal model which permits sampling of arterial blood and bile from unanesthetized rats with uninterrupted enterohepatic circulation is described. Pharmacokinetic data concerning inulin (0.2 μmol kg‐1) and terbutaline (1.8 μmol kg‐1) after intraarterial injection are presented. The following values for inulin were obtained Vdβ= 0.25 ml g‐1plasma clearance = 2.3 ml min‐1kg‐1and bile clearance = 0.03‐0.04 ml min‐lkg‐1, which mainly are in agreement with data from the literature. For terbutaline the corresponding values were 0.58 ml g‐l, 5.2 ml min‐lkg‐land 0.12‐0.98

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10017.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe permeability of eel gills to ions, lipid‐soluble and ‐insoluble substances has been measured under steady‐state conditions. The results obtained support the multi‐pathway model for transcapillary transport (Stray‐Pedersen and Steen 1975). The gills are 7.5 times more permeable to THO than to Na+or K+. Metabolic inhibitors do not affect the transfer of substances across the gills. Exposure to EDTA or MS‐222 changes the permeability properties to resemble those of an aquous barrier. The gills are 10 times less water permeable than the capillaries of there

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10018.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractWith clearance technique, changes in tubular reabsorption of solute free water(TH2Oc), were studied in a group of 9 healthy hydropenic volunteers during a cold stress of 1 h at + 15°C.Increases were found in(TcH20)and in fractional excretion of sodium and osmoles during cold.Since(TCH2O)was used as an index of sodium reabsorption in the ascending limb of Henle's loop, the findings indicated that under the conditions used in this study, the concentrating ability of the kidney was not negatively influenced by cold, despite a significant increase in arterial pressure.It is suggested that the reabsorption by the ascending limb of the loop was increased secondary to a reduced proximal tubular reabsorption of sodium

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10019.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe contraction response to transmural stimulation in the bovine iris sphincter muscle was abolished by atropine but was left virtually unchanged by hexamethonium, and by adrenergic neuron and receptor blockers, indicating activation of postganglionic cholinergic nerve fibres. Low doses of prostaglandins E1, E2and F2α(0.1–5.0 ng/ml) consistently and apparently in a dose‐dependent manner enhanced the contraction response to transmural stimulation. Prostaglandins E1and E2were equipotent while F., was at least 10 times less active. Within the same dose range the prostaglandins also enhanced the contraction response to exogenous acetylcholine, indicating that part of the enhancing effect of the prostaglandins on neuromuscular transmission was due to a postjunctional action. A spontaneous increase in tone of the preparation commonly occurred about 1 h after the beginning of the experiment. SC 19220, a potent antagonist of prostaglandin action, reduced the tone and the contraction responses as well as the enhancing effect of the prostaglandins. It is concluded that prostaglandins might serve the function of controlling neuroeffector transmission and muscular tone in the sphincter muscle of the bovine

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10020.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe effects of catecholamine‐infusions and of hypoxia on lung blood volume and on extravascular lung water content have been studied in anesthetized cats with opened chests. To this end a biopsy technique, with isotope labelling of blood and with successive removal of the smaller lung lobes, was employed. Mean pulmonary arterial pressure increased by 30–75% upon infusing catecholamines or upon inducing general hypoxia, the latter stimulus being the more powerful one. Pulmonary blood volume did not increase during these procedures, where an active constriction of pulmonary vessels thus apparently took place. The extravascular lung water content was found to be reduced in animals infused with noradrenaline or ventilated by hypoxic air, whereas a small increase was observed in the animals receiving adrenaline. This difference might reflect domination of precapillary vasoconstriction in the former groups, whereas post‐capillary vasoconstriction could be more pronounced with adren

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10021.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractUpon submersion, the domestic duck normally displays a prompt but modest cardiac retardation, which, after a short delay, is reinforced into a pronounced state of bradycardia. The present study has revealed that arterial asphyxia is a prerequisite for the reinforcement of the initial slight bradycardia.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10022.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractIn order to study the extent and degree of specificity of the removal of circulating noradrenaline (NA) from the blood stream, during a single passage through the vascular beds of the lungs and of the forearm musculature of unanaesthetized, healthy young men, the following radiometric method was used: A mixture of3H‐NA with14C‐inulin and125I‐labelled human serum albumin was injected proximally to the bed under study; six serial blood samples were drawn distally to it, with about 15 s interval, and the disappearance of3H‐NA relatively to that of14C‐inulin and125I‐albumin was determined.3H‐NA was found to be removed from the blood stream in both these vascular beds. However, in the forearm the removal of3H‐NA was much greater, and apparently to a large extent due to specific trapping in the tissues, since the clearance of3H‐NA over the vascular bed of the forearm markedly exceeded that of 14C‐inulin. During passage through the lungs removal of3H‐NA was less marked, and apparently largely unspecific, since it was initially essentially equal to that of14C‐inulin. This suggests that removal of circulating ergones of small molecular sire, from the blood stream passing through the lungs, may occur initially by unspecific filtration/diffusion. Their subsequent fate would depend on whether the extraluminal tissues, supplied by the lung circulation, possess specific mechanisms for concentrating and/or inactivating e

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10023.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractRat liver mitochondrial enzyme activities were measured after exposing the animals to the atmospheric pressure of 380 mm Hg for 5 h and 14 days. Succinate dehydrogenase and succinate oxidase activities increased significantly during the hypoxic period of 14 days. No change was observed in cytochrome oxidase activity. Malate dehydrogenase and glutamate dehydrogenase activities increased somewhat, but not significantly. The efficiency of oxidative phosphorylation (the ADP: O ratio) in the isolated mitochondria remained unchanged. The exact mitochondrial protein values showed a 15% decrease as compared with the control group. The concentrations of cytochromes did not change significantly in the hypoxic group. During the short hypoxic period succinate dehydrogenase, succinate oxidase and cytochrome oxidase activities increased as compared with those in the control group.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10024.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Abstract15 μm and 35 μm radioactive microspheres, differently labelled, were used simultaneously for rCBF‐determinations in monkeys. Flow values calculated from data for 35 μm spheres were 27±7 g/min per 100 g higher for grey matter and 10±3 g/min per 100 g lower for white matter than flow values calculated from 15 μm spheres, while both sphere sizes resulted in similar values for the choroid plexus. A large number of 35 μm spheres were trapped in extracerebral pial arterioles. It is concluded that entrapment in relatively large arterioles of the 35 μm spheres explains the differences in flow values, and that this invalidates the use of 35 μm spheres, and larger, in rCBF‐de

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10025.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe number of acetylcholine receptors at normal and denervated end‐plates in rat soleus muscles was studied using the binding of [125I] α‐bungarotoxin as a quantitative assay. Normal end‐plates bound several thousand times as much toxin as equal areas of extra‐synaptic muscle membrane. After short‐term denervation (up to 2.4 weeks) the extrajunctional binding increased, but there was no change in specific binding to the motor end‐plate. Denervation for longer periods (up to 7 weeks) reduced binding sites at the end‐plate by up to 60–70%. Direct electrical stimulation of these muscles for the entire period of denervation did not prevent the loss of junctional binding sites even though it was adequate to abolish the increase in extrajunctional toxin binding. In contrast, denervated end‐plates on muscle fibres cross‐innervated by a Foreign nerve at a distant location continued to bind normal amounts of toxin

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb10026.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY