摘要:

SUMMARY1. To examine individual hormonal responses to extreme physical stress, blood samples were taken from eight highly trained athletes 1 day before and within 15 min of finishing the 1986 1000 km Sydney to Melbourne Ultramarathon foot race.2. The baseline hormonal state of these highly trained athletes was quite different from normal. Resting serum conjugated catecholamines — epinephrine (E), nor‐epinephrine (NE), dopamine (D), free E and free D — were significantly elevated above the normal mean (P<0.01). ACTH levels were significantly elevated above the normal range. Immunoreactive β‐endorphin (IR‐βEP), growth hormone (GH), prolactin (PRL), testosterone, cortisol and cortisol‐binding globulin (CBG) were within the normal range.3. The effect of the race on serum catecholamine levels was to elevate further free and conjugated NE (P<0.01). Other catecholamines, free and conjugated, remained significantly elevated above the normal mean (P<0.01). Adrenocorticotrophic hormone (ACTH) remained elevated, and IR‐βEP within the normal range, without significant change. A significant increase in GH (P<0.05), PRL (P<0.01), and cortisol (P<0.01) was seen, with no change in CBG.4. As a model of chronic physical stress, the ultramarathon runner demonstrates a significantly altered baseline hormonal state as reflected in the primary mediators of the stress response, the catecholamines and the hypothalamic‐pituitary‐adrenal axis. Their response to severe exercise is distinct from that of untrained individuals in whom conjugated catecholamines decrease and ACTH increase. This may represent hormonal adaptation

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01571.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The concentrations of gamma‐amino butyric acid (GABA) and glutamate were measured in the brains of chickens which were treated with furazolidone (FZ) or nitrofurazone (NF) at oral doses of 12.5, 25 or 50 mg/kg for 5 days.2. At the end of the treatment, the birds lost about 9% of their bodyweight when on the small dose of FZ or NF and about 18% when on the high doses.3. Both drugs produced dose‐dependent increases in the concentrations of GABA and glutamate which were statistically significant at doses of 25 and 50 mg/kg of NF, and 50 mg/kg of

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01572.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The effects of intravenous (i.v.) morphine on adrenocorticotrophic hormone (ACTH), β‐endorphin (β‐END), total catecholamines (CA) and histamine (HIS) plasma concentrations, were determined in anaesthetized dogs at 30°C and 37°C.2. Hypothermia initially increased CA levels by 29%, but the values returned to baseline after 2 h. Morphine (1 mg/kg, i.v.) produced a significant decrease in CA both at 37°C and 30°C (34% and 54%, respectively). Subsequent administration of naloxone (1 mg/kg, i.v.) significantly increased CA levels in both groups.3. Hypothermiaper sehad no effect on ACTH, β‐END, and HIS concentrations. Morphine produced a significant increase in pituitary hormones and HIS, in hypo‐ thermic but not in normothermic animals. Morphine concentrations were significantly higher at 30°C during the first 45 min.4. The results suggest that the effects of morphine on hormonal and histamine release observed at 30°C are concentration‐dependent and related to changes in morphin

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01573.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. This study tests the hypothesis that suppression of Na+ pump would increase the rate of tension development and the magnitude of contraction induced by cooling in airway smooth muscle.2. Rat tracheal preparations were incubated in ouabain for 8 h and tested hourly for their response. In a representative specimen the rate of tension development increased from the control value of 0.7 mg/s to 5.5 mg/s after 7 h of incubation in ouabain concentration of 4 × 10−4mol/L; likewise, the magnitude of contraction increased from the control value of 80 mg to 550 mg.3. Using ouabain concentrations between 9 × 10−5mol/Land6 × 10−3mol/L, the rate of tension development and the magnitude of contraction first increased in a dose‐dependent manner up to 8 × 10−4mol/L, then declined with higher doses but the responses were still greater than the control values at all concentrations.4. After 3 h incubation in ouabain at 8 × 10−4mol/L, the mean rate of tension development and the mean magnitude of contraction increased to 647% and 578% of the control value, respectively.5. These results indicate that depression of Na+pump results in hypersensitivity and hyper‐reactivity of the airway smooth

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01574.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The basal blood pressure and the drug‐stimulated pressor response were studied in male offspring in the sixth generation (5d‐PTx‐F6) of rats parathyroidectomized on day 5 of pregnancy.2. The systolic blood pressure in conscious 5d‐PTx‐F6rats measured by a tail cuff was significantly higher (P<0.001) than in control rats.3. Venous plasma renin activity was significantly lower (P<0.001) in the 5d‐PTx‐F6rats. Plasma levels of calcium, sodium, and potassium in the 5d‐PTx‐F6rats and in the controls did not differ.4. Systolic arterial pressure response to intravenously (i.v.) administered angiotensin II (150 ng/kg) in the 5d‐PTx‐F6rats was significantly greater than in the controls (P<0.05), when blood pressure was measured directly through a pressure transducer under anaesthesia.5. Pressor responses to norepinephrine (5 μg/kg, i.v.) in the 5d‐PTx‐F6rats were significantly lower (P<0.05) than in the controls, when blood pressure was measured directly under anaesthesia.6. The findings suggest that the 5d‐PTx‐F6rats undergo functional alterations of the renin‐angiotensin and sympathetic nervous system

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01575.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. A method for determining free Ca2+‐ions in the erythrocyte is described, using a commercially available ORION‐Ca‐electrode and calomel reference electrode assembly, where changes in free Ca2+‐ion concentration upon addition of 0.01% digitonin could be measured.2. The average value found for fresh cells from 20 healthy donors at 37°C (pH = 7.4) was 0.20 ± 0.04 μmol/L referred to a haematocrit of 10%.3. Decrease of the simultaneously determined adenosinetriphosphate (ATP) concentration indicates that ATP is presumably needed to activate the Ca‐ATPase.4.In vitroaddition of the calcium antagonists pentoxifylline and nifidepine, respectively, induced a normalization of the intraerythrocytic Ca2+‐ion concentration after previous increase with the ion carrier ionophore A23187.5. The advantages and possible clinical applications of this method

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01576.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. Cortico‐lingual and linguo‐cortical interconnectivity was investigated in ketamine‐anaesthetized rats mounted onto a stereotaxic apparatus. The tip of the tongue was tied to a force displacement transducer to monitor tongue retrusions. The tongue cortical area was exposed in one or both hemispheres to record evoked potentials or spontaneous electroencephalographic (EEG) activity, or to stimulate electrically with single square pulses of up to 50 V and 0.25 ms pulse width.2. The results showed that (i) tongue retrusions elicited by electrical stimulation were identical to those induced by ketamine; (ii) ketamine‐induced tongue contractions correlated in time with cortical EEG potentials which were easily distinguished from the background noise; (iii) haloperidol (2.5 mg/kg, i.m.) suppressed the cortically evoked tongue contractions as well as the ketamine‐induced contractions.3. These results suggest that ketamine‐induced tongue retrusions may involve the cortex in their mediation if not their generation and that this may provide a basis for the suppression of dyskinetic activity during sleep or unco

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01577.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. A ‘tissue perfusion monitor’ (TPM) to non‐invasively provide an index of skin blood flow (SkBF) has been developed; it employs photoelectric plethysmographic principles to measure changes in the nett flux of red blood cells in superficial microvasculature.2. The ‘tissue perfusion index’ (TPI) varies in proportion to SkBF, provided local haemoglobin concentration does not change significantly. TPI of humans and experimental animals has been shown to indicate reliably, well established phenomena such as decreased SkBF in response to mechanical restriction, cold or Valsalva's manoeuvre, or increased SkBF in response to heat, acetylcholine, sodium nitrite or local nerve blockade.3. SkBF in sheep was varied between 1 and 156 mL/100g per min as measured with radioactive microspheres. Simultaneous measurements were made using the TPM and four laser‐Doppler instruments. The TPI yielded a correlation coefficient of 0.938, and when data were expressed as percentage change, the regression line did not differ significantly from the line of identity and the root‐mean‐square‐error was 6.2%. Data for the laser‐Doppler indices of SkBF were, respectively, 0.549–0.786, highly significant deviations in slopes, and 13.6–16.7%.4. Thus, the TPI is a reliable index of changes in SkBF. Compared with some other available instruments, the TPM is more precise; it is also less sensitive to movement artefact, can be completely portable by battery operation, probes can be multiplexed to a single meter and it is likely to be much less expensive than current lasers.5. Applications include, for example, experimental investigations of SkBF in man and animals, clinical uses such as evaluation of the efficacy of regional nerve blockade or of circulatory restitution after reconstructive surgery, and clinical tests of

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01578.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. To determine the response of plasma atrial natriuretic peptide (ANP) to treatment with an angiotensin converting enzyme (ACE) inhibitor in heart failure, seven patients (NYHA Functional Class III‐IV) were studied before and after the addition of ramipril to maintenance digoxin and diuretic treatment.2. Baseline arterial ANP levels were raised, but fell during ramipril treatment in parallel with changes in both haemodynamic recordings (arterial pressure, pulmonary artery diastolic pressure, and right atrial pressure) and hormone levels (antiotensin II and aldosterone).3. Coronary sinus ANP, measured in three patients, was greater than concomitant arterial levels, and the coronary sinus ANP secretion rate was calculated to be between 15 and 119 pmol/min.4. These results demonstrate that improvement in haemodynamic function during ACE inhibitor treatment is associated with a decline in elevated ANP levels, and support the concept that atrial stretch or pressure regulates the secretion of atrial peptides in ma

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01579.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The effects of papaverine, an adenosine uptake inhibitor, were tested against theophylline‐induced seizures.2. Rats were infused with a constant intravenous infusion of theophylline at 10.3 mg/min immediately following intraperitoneal pretreatment with either papaverine 35 mg/kg or saline vehicle.3. Papaverine produced a potent proconvulsant effect towards theophylline seizures, reducing the onset time and cumulative dose to seizure and theophylline concentrations in arterial serum, cerebrospinal fluid and brain, respectively, at onset of maximal seizure

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01580.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY