摘要:

Intrarenal blood flow, nephron function and whole kidney function were studied in the recovery phase of acute renal failure induced by 45 min of warm ischemia. Analyses were made 24 h, 7 days and 28 days after the ischemic insult. At 24 h the total renal blood flow was 4.0 ml min‐1g‐1, decreasing to 1.2 within one week. After four weeks it was normalized to 3.4 ml ˙ min‐1˙ g‐1. The intrarenal blood flow distribution, studied with the 86‐Rb extraction method, showed the same pattern of response, with no signs of a persistent heavy reduction in the deeper parts, as was found 10 min after recirculation (Karlberg et al. 1982a). The contralateral, nonischemic kidney responded with hyperemia in all areas 24 h after the trauma, but after 7 days the values were normal. The function of the superficial nephrons was studied with the micropuncture technique. In the initial phase mainly obstructed nephrons were found, but after four weeks the nephrons were essentially normal. After 24 h the postischemic kidneys were anuric but at 7 days urine production had started and the GFR was 0.1 ml min‐1; this improved to 0.55 ml min

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07039.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The 86‐Rb extraction method was applied for a study of regional renal blood flow. In the cortex, a samling time of 30 s led to an underestimation by about 15% as compared with the microsphere method. This was due to incomplete cortical cellular extraction of rubidium with subsequent rapid wash‐out the tracer. In the renal medulla, a sampling of 30–60 s gave valid data with almost complete extraction. A sampling time of only 10 s, i. e. a time similar to the intravascular transit time, gave rise to a 50% underestimation of the inner medullary blood flow. Errors due to transport of rubidium by the tubular fluid were investigated in detail. A theoretical analysis based on equilibrium data revealed a maximal error of about 5%. Studies with micropuncture of distal tubules and studies of the urinary transport showed no or negligible contamination from tubular urine. Under control antidiuretic conditions the blood flow in the cortex was 5.2±0.2 ml‐min± g± (mean±SE, n=16), in the outer stripe of the outer zone 2.2±0.1, in the inner stripe 1.5±0.1 and in the inner z

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07040.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

20 subjects were studied at rest and during a 25 min submaximal exercise (65% of VO2max) on two occasions, the first preceded by a fat rich diet and the second by a carbohydrate rich diet. Oxygen uptake, respiratory exchange ratio (R) and arterial‐femoral venous differences for glucose, lactate, β‐hydroxybutyrate and FFA (based on the fractional extraction of3H‐palmitate) were measured at rest and during exercise. Changes in intramuscular glycogen, triglyceride and lactate concentrations were determined in muscle biopsies taken before and immediately after exercise form m. quadriceps femoris. R was lower after the fat than after the carbohydrate diet and simultaneously the FFA extraction by the exercising leg was higher. The muscle triglycerides did not changes significantly during exercise after either diet. The glucose extraction was insignificantly greater after the fat diet. The glycogen reduction was numerically smaller after the fat diet, but the difference was uncertain and difficult to evaluate due to a large variation after the carbohydrate diet. However, muscle lactate accumulation and release by the exercising leg was smaller after the fat diet, indicating a slower rate of muscle glycogenosis. It is concluded that a fat rich diet increases the relative contribution of fat to the oxidative metabolism, that this increase, to a great extent, is covered by plasma FFA and that the concomitant decrease in carbohydrate utilization concerns muscle glycogen rather than blood g

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07041.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The sulfhydryl (SH) inhibiting para‐substituted mercuribenzoates like pOHMB caused a myotonia which appeared as a smooth myotonic profile during recording of the response to twitch stimulation (0.1/s) of isolated rat diaphragm preparations. The maximum myotonic tension varied from about 10% to 200% of the twitch tension at pOHMB addition, and the myotonic repetitive action potential activity varied from a few to more than one hundred action potentials in different cells of the same preparation. The myotonia did not appear after pretreatment with the SH‐reducing agent dithiothreitol, and both dithiothreitol and N‐ethyl‐maleimide inhibited the myotonia. The myotonia increased with temperature, appearing at about 32°C. Increased twitch frequency and tetanic stimulation decreased the myotonia. No change of threshold was observed in myotonic preparations. The myotonia was depressed in K+‐free solution, and it was blocked by K+concentrations exceeding 1.5× normal. The myotonia was reduced when the NaCl was replaced by sucrose or choline chloride. In Ca2+‐free solution the time to maximal myotonic tension and the variability of the maximal myotonia were reduced. Ca2+concentrations above normal inhibited the myotonia. No myotonia was observed in the slow twitch soleus muscle. pOHMB also caused a twitch depression during indirect and direct stimulation. The depression was observed in soleus muscle and in the diaphragm below 30°C. The depression was thus independent o

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07042.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Water and salt balance was studied in the same goats during pregnancy, lactation and anestrus. All goats increased their water intake during the course of pregnancy, but individual differences were large. In general, twin pregnant (TP) goats drank more water than single pregnant (SP) animals (3.4±0.4; N=11 as compared to 2.5±0.3 litres/day; N=5) during the last weeks of pregnancy. During lactation the high water intake of TP goats persisted and the SP animals increased their intake to the same level as the TP goats. The water intake was reduced to about 2 1/day in both categories of animals during anestrus. Urine volume largely followed the changes in water intake in the individual animal. A continuous decrease in urine osmolality during the course of pregnancy occurred, but during lactation urine osmolality increased towards anestrus levels. TP goats generally retained more sodium than SP animals during pregnancy and during anestrus, whereas the figures were similar during lactation. Plasma Na, K and osmolality remained unchanged during pregnancy, lactation and anestrus, but a large fall in total plasma proteins and a moderate fall in hematocrit were observed during the course of pregnancy. Glomerular filtration rate of TP goats was elevated by about 35% during the 4th month of pregnancy, but did not differ from anestrus levels during the 3rd and 5th month or during lactation. Effective renal plasma flow was highest during the 3rd pregnancy month and then fell to reach lactation and anestrus levels during the 4th month of pregnancy. A few hours before parturition the animals became markedly dehydrated as shown by sudden increases in plasma Na, K, osmolality, total proteins and hematocrit. This water deficit was replenished within 26 h post‐par

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07043.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Olfactory receptor activity was studied in the char by two methods: (a) recording of the electro‐olfactogram (EOG) with two electrodes simultaneously in the olfactory pit and (b) recordings from the olfactory bulb during olfactory stimulation and progressive removal of lamellae in the olfactory rosette. As stimuli were used methionine representing the amino acids and dilute char bile representing the bile salts. By cross‐adaptation studies it was demonstrated that receptors sensitive to each of these two stimuli are functionally independent. The results show further that both types of receptors may be found on all lamellae, but differentially distributed within each lamella. Receptors sensitive to methionine are located closer to the raphe than receptors sensitive to bile. The spatial differentiation persists regardless of stimulus concentration. The results are discussed in relation to the projection and growth of primary nerve fibres into the olfactory bulb, and the existence of receptor cells with microvilli and with ci

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07044.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

In view of the fact that diazepam has been shown to prevent an increase in catecholamine synthesis and/or turnover rates in stressful situations, and to modify the cerebral metabolic (and circulatory) response to hypoxia and hypercapnia, the influence of the drug on synthesis rates of DOPA and 5‐HTP in three regions of the rat brain were studied under normoxic‐normocapnic conditions, as well as in hypoxia and hypercapnia. In order to exclude a modifying influence of variations in tissue pO2during hypercapnia, cerebral venous pO2was kept at control values by moderate arterial hypoxia. When compared to the control state (paralyzed animals maintained on 70% N2O) normoxic and normocapnic animals given diazepam (in the absence of N2O) showed a slightly enhanced DOPA synthesis in limbic structures and reduced 5‐HTP synthesis in limbic structures and striatum. In hypoxia, the drug considerably curtailed DOPA synthesis in limbic structures and striatum but had no effect on synthesis rate in cortex. The drug also appeared to exaggerate the generalized reduction in 5‐HTP synthesis observed under 70% N2O. In hypercapnia, diazepam reduced the enhanced rate of DOPA synthesis (observed under 70% N2O) in striatum but left that in the cortex unchanged. The drug prevented the hypercapnia‐induced increase in 5‐HTP synthesis, observed under 70% N2O. It is concluded that diazepam significantly alters dopamine and serotonin synthesis in hypoxia and hypercapnia. Probably an indirect action, perhaps related to the stress‐alleviating effect of diazepam, is involved. The results suggest that the effect of the drug on cerebral metabolic rate and blood flow in hypoxia and hypercapnia is unrelated to changes in noradrenaline synthesis or turnover. Furthermore, although the results demonstrate that diazepam modulates dopamine metabolism in hypoxia and hypercapnia it seems questionable that this influence can explain the metabolic and circulatory effects of diazepam in the

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07045.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Spontaneous activity responses to acetylcholine (ACh), adrenaline (A), noradrenaline (NA) and barium chloride as well as the effects of various autonomic drugs on effects of field stimulation of nerves and muscle cells of isolated pieces or strips of cauda epididymidis, vas deferens, ampulla ductus deferentis and prostate of dog were studied. The main results and conclusions are: the muscles show little spontaneous activity but rhythmicity can easily be produced by e. g. stimulating agonists. The muscles are contracted by α‐adrenoceptor stimulants. ACh has usually no or a very weak contractile effect in high concentrations. Muscles of young dogs are more sensitive to ACh. The excitatory innervation of the muscles is adrenergic and completely blocked by adrenergic neuron blockers as well as α‐adrenoceptor blocking drugs. Stimulation of adrenergic nerves leads to maximum response already at low frequencies (4–6 Hz). This response is very similar to that provoked by a supramaximal dose of NA. Scopolamine enhances neurogenic contractile effects while physostigmine suppresses them. Hence cholinergic nerves may act by muscarinic prejunctional inhibition of the excitatory adrenergic neurotransmission rather than act directly upon the smooth muscle cells. Since secretory cells receive cholinergic innervation prejunctional inhibition of the adrenergic myomotor nerves may be of functional significance in at least the long copulatory events of

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07046.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The relationship between work intensity and body temperature was investigated in the rat in an attempt to clarify whether alterations in thermoregulatory capacity can modify the rate and extent of body warming during exercise. Repeated noradrenaline injections led to increased hyperthermic response to that amine. However, during exercise these animals did not attain higher colonic temperatures as did the animals avoiding noradrenaline treatment. If noradrenaline was injected 60 min prior to test‐exercise the body temperature of the rats rose to a higher level than without the drug. The extent of this rise was, however, independent of the previous noradrenaline‐treatment history. Beta blockade abolished the noradrenaline‐induced hyperthermia but not the exercise‐induced hyperthermia. Despite increased capacity for heat production, cold‐acclimated rats did not attain higher colonic temperatures during exercise than did the running‐trained, cold‐stressed or sedentary control rats. However, the higher tail skin temperature of the cold‐acclimated rats indicate that their heat production was enhanced but they maintained lower colonic temperature by dissipating the excess heat through the elevated blood flow to the tail and probably to other extremities. These results indicate that the rise in deep body temperature of the rats during work is proportional to work intensity and that the enhanced heat production capacity can be compensated for by increasing the heat

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07047.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The influence of short‐term adaptation to a fat and protein enriched diet (F+P) and a carbohydrate enriched diet (CHO) on skeletal muscle lipoprotein lipase (LPL) activity and muscle glycogen levels was evaluated in 7 males. Muscle biopsies were taken from the m. vastus lateralis after an uncontrolled, mixed diet (M), after a 3 day F+P diet preceded by intense exercise, and after a 3 day CHO diet. After the F+P diet glycogen concentration was 55% that of the M diet while LPL activity increased by 21% (n. s.). After the CHO diet glycogen levels increased by 82% and LPL activity decreased by 55% compared to the M diet (p<0.01). The changes in LPL after the CHO diet were related to the changes in glycogen concentration (r = 0.98,p<0.01). LPL activity in the control situation was directly related to percent slow twitch (ST) muscle fibre type (r = 0.95,p<0.01). The results suggest that the uptake of fat from the circulation may be actively regulated by the muscle as a function of intramuscular substrate availability and that this regulation may be related to muscle fibre type compositio

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb07048.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY