摘要:

AbstractRats treated with decaborane exhibited a marked reduction in the noradrenaline (NA) content of heart, liver, and spleen but no significant fall in adrenal catecholamines. Decaborane‐treated animals excreted less NA but more adrenaline (A) than control animals. When exposed to 3° C, control animals survived and showed increased NA excretion in contrast to decaborane‐treated rats, which, however, responded with increased excretion of A until death after 4–6 days. Unlike adrenalectomized controls adrenalectomized rats treated with decaborane failed to increase their NA excretion during cold exposure and died in less than 20 hrs. The survival of cold‐exposed animals appears to be related to the liberation of NA, with A release serving as an important secondary mechanism of defense against cold. The results suggest that decaborane treatment curtails the supply of NA in vivo, presumably owing to inhibition of s

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03410.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe vasoconstrictor effect of intermittent lumbar sympathetic stimulation of the hindleg of the rabbit, pretreated with noradrenaline (NA)‐depleting doses of decaborane or prenylamine, rapidly subsides in contrast to untreated controls. When the interval between the trains of stimuli is increased a partial recovery of the stimulation response is observed, suggesting an accumulation of transmitter, probably as a result of continuous resynthesis. Injection of NA (1–5 μg/kg) or dopamine (50–100 μg/kg) also causes an enhanced stimulus response, suggesting uptake of NA and increased rate of synthesis, respectively. An increase in stimulation response was observed after administration of dopa in prenylamine‐treated but not in decaborane‐deple

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03411.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe development of five intestinal dipeptidase activities (L‐alanyl‐L‐glutamic acid, L‐alanyl‐L‐proline, glycylglycine, glycyl‐L‐leucine and glycyl‐L‐valine dipeptidase activity) in the rat from 15 dayspost coitumup to 3 weekspost partumwas investigated and related to the structural development of the rat small intestinal mucosa. Very low enzyme activities were found in the period of mucosal cell proliferation (15 to 18days post coitum). At 18 1/2 dayspost coitumthe period of mucosal cell differentiation was commencing, and simultaneously the dipeptidase activities began increasing to reach maximal values at parturition, by which time the differentiation was finishing. Within a few hours of birth, when the newborns had suckled, an abrupt and significant fall to the relatively low adult level was observed for four of the dipeptidase activities. The fifth enzyme activity (L‐alanyl‐L‐proline dipeptidase) declined more slowly postnatally and first reached the relatively low adult level during the 3rd weekpost partum.The relation of the changes in the intestinal dipeptidase activities to the structural characteristics of the mucosa during the devel

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03412.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe CO, buffer capacity of brain tissuein vivowas studied by measuring the tissue bicarbonate concentration at various tissue CO2tensions in rats which were either hyperventilated, or breathed various CO2concentrations spontaneously for 30 min. Measurements of the tissue lactate content indicated that the technique of freezing the tissuein situdid not lead to tissue hypoxia. The main increase in the tissue bicarbonate concentration at a given inspired CO2concentration occurred within 30 min, but there was a slow further increase from 30 to 180 min. The values did not differ significantly between groups anesthetized with pentobarbital or phenobarbital and they were not influenced by variations of the inspired oxygen concentration from 20 to 50%. The mean tissue bicarbonate concentration was 16.0 meq/kg tissue H2O at a tissue CO2tension (PtCO2) of 40 mm Hg. The buffer capacity of the tissue, defined as βCO2= d log PtCO2/d log (HCO3/PtCO2· S2) was 1.5. This means that when the CO2tension was changed from 20 to 120 mm Hg, the tissue bicarbonate concentration increased from 12.5 to 22.5 meq/kg tissue H2O. Theoretical derivation of an equivalent buffer system with the same buffer capacity showed that at least 35 mmoles of buffer/kg tissue H2O were needed to explain thein vivobuffer capacity of the tissue. The theoretical buffer system made it possible to derive buffer base values for the tissue, and to construct a curve for the calculation of base excess value

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03413.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractAdreno‐demedullated rats subjected to a moderate cold exposure showed a significant increase in urinary excretion of noradrenaline (NA) and maintained their thermal equilibrium. Adrenodemedullated rats, chronically pretreated with guanethidine, however, failed to respond with an increase in NA excretion upon exposure to 3° C and all the animals died 7 days later following a fall in urinary NA. These results suggest that the survival of cold stressed adreno‐demedullated animals is dependent upon a peripheral secretion o

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03414.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractExperiments were conducted with and without addition of 1 per cent cholesterol to diets containing 20 per cent of fats of the following types: 1. corn oil, 2. 19.5 per cent hydrogenated coconut oil and 0.5 per cent corn oil, and 3. 12 per cent hydrogenated coconut oil and 8 per cent olive oil. Following a 3 weeks' pre‐experimental period on a fat free diet adult female rats were given the experimental diets for 6 weeks. In rats given cholesterol corn oil caused the well known transfer of cholesterol from plasma to the liver. In rats given diets containing cholesterol and corn oil the cholesterol content of the liver was considerably higher and serum cholesterol much lower in rats given the diet containing olive oil. The result indicate that linoleic acid probably enhances cholesterol absorption over and above the effect of oleic acid. The carcass cholesterol of rats given corn oil was slightly lower than in rats given type 2 of fat. The difference was statistically significant on cholesterol free diets. When various tissues were analysed corn oil induced transfer to other tissues than the liver could not be observe

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03415.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractRats were given a diet free of polyenoic fatty acids and containing 1 per cent of cholesterol until 150 days old. Severe hypercholesterolemia and livers containing several per cent of cholesterol resulted. Next 80 mg of cod liver oil was given daily to each rat for 14 days. The result was that about 28 mg of cholesterol disappeared from a rat body per day. The pathways responsible were not further studied.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03416.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractIn acute experiments on cats anesthetized with chloralose, inhibition of excitatory vagal responses of gastric smooth muscle was produced by reflex or direct activation of an adrenergic nerve fibre system. The reflex that could be elicited by distension of a jejunal loop or stimulation of mesenteric afferents was dependent on intact spinal connections because it was blocked by spinal anesthesia. Activation of the adrenergic nerve fibre system did not inhibit gastric myogenic tone or gastric muscle contraction elicited by the muscarinic action of acetylcholine. It was therefore concluded that the adrenergic outflow responsible for this type of inhibition acts on parasympathetic intramural ganglion cells involved in the excitatory control of gastric motility.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03417.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractIntracellular electrodes were used for studying the responses of frog muscle fibers to linearly rising currents over a wide range of gradients (0.4–400 μA/sec) corresponding to spike latencies up to 1 sec. In fibers with normal resting potential the critical firing level showed no significant variations at different gradients. With lowering of the gradient there was a successive decrease in stimulus threshold and a moderate reduction in spike height. Even a small reduction of the resting potential resulted in typical changes of the spike responses characterized by a pronounced reduction in amplitude and increase in duration as the gradient was lowered until a minimal gradient was reached below which no spike was generated. The response patterns in normal and depolarized fibers were correlated to the slow active subthreshold processes occurring in muscle fibers during stimulation with linearly rising curren

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03418.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractRat peritoneal mast cells, when incubated in histamine‐H3containing medium, were shown to take up and concentrate histamine. The uptake was proportional to incubation time and to extracellular histamine concentration. Metabolic inhibitors did not significantly affect the uptake. The exogenous histamine was bound to mast cell granules in about the same proportion as found for the endogenous. Treatment of mast cells with compound 48/80 released the same relative amounts of both exogenous and endogenous histamine. These results suggest that histamine was taken up by passive diffusion and stored in the mast cell granules. High concentrations of 5‐HT inhibited the histamine uptake, whereas histidine and 5‐HTP did not influence the pr

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1966.tb03419.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY