摘要:

SUMMARY1. The intravenous administration of nicergoline (5 mg) was followed by a rapid and sustained lowering of blood pressure; less rapid effects were bradycardia and an elevation of cardiac output. These delayed effects are consistent with an indirect action on the α‐adrenoreceptors of the central nervous system.2. Following the oral administration of nicergoline (30 mg), a partial reduction of exercise‐induced lactacidaemia was demonstrated, which is consistent with the haemodynamic changes shown at

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00051.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. The 24‐h urinary excretion of tritium after tritiated adrenaline administration and digital vascular reactivity to exogenously administered adrenaline and noradrenaline were measured in ten normotensive and in twenty‐eight labile essential hypertensive subjects. Tritiated noradrenaline excretion and apparent noradrenaline secretion rate were also measured in ten and eleven of these subjects, respectively.2. Despite overlapping, the mean 24‐h tritium excretion after 3H‐adrenaline administration as well as reactivity to adrenaline were significantly greater in the hypertensive than in the normotensive subjects, whether or not they had increased responsiveness to noradrenaline. Significant correlation, however, was observed between tritium excretion of adrenaline and reactivity to adrenaline in both labile hypertensive and normotensive subjects. These measurements were also both significantly correlated with percentage variability in systolic and diastolic blood pressure in the labile hypertensive subjects.3. No significant correlation was observed between adrenaline as against noradrenaline measurements, whether physiological or biochemical, in either hypertensive or normotensive s

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00052.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. The present study examines the modulation, by parathyroid hormone, of the changes in myocardial contractile force induced by isoprenaline, propranolol isomers, verapamil, and nadolol.2. Cardiac contractile force was estimated by the use of guinea‐pig isolated auricles. Synthetic bovine 1‐34 parathyroid hormone (sPTH) alone did not modify contractile force; conversely, sPTH significantly inhibited the cardiode‐pressant effect ofl‐propranolol,d, l‐propranolol,d‐propranolol, and verapamil. These results suggested an action of sPTH independent of β‐adrenoceptors. Against an hypothesis of a single, non‐β‐adrenoceptor mechanism of sPTH action on the heart are the following observations: (i) when β‐adrenoceptors were blocked with nadolol, sPTH no longer inhibited the cardiodepressant effect of propranolol, (ii) sPTH reduced the inotropic effects of isoprenaline. Our conclusion, therefore, is that sPTH probably affects cardiac muscle contraction by at least two mechanisms, one of which involves non‐adrenergic transmembrane calcium flux and the second β‐adrenoceptors.3. When these studies were extended into the clinical pharmacological field, it was found that plasma ultrafiltrates from severely hyperparathyroid patients in chronic renal failure inhibited like sPTH the cardiodepressant action of propranolol. No such effect was seen with ultrafiltrates from parathyroidectomized patients. Accordingly, high PTH levels may inhibit the action of cardiotropic drugs administered to hyperparathyroid patients, and may be one factor in the cardiomyo

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00053.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. The effects of systemic hypoxia, arterial occlusion and muscle exercise on blood flow and oxygen uptake of the hind limb of anaesthetized areflexic dogs were assessed. The control responses were compared to those elicited after administration of meclofenamic acid (2 mg/kg, i.v.).2. Meclofenamic acid reduced resting blood flow by approximately 20%.3. The increase in blood flow during 6 min periods of hypoxia was inversely related to arterial oxygen saturation and this relationship was not altered significantly by meclofenamic acid.4. The magnitude of the reactive hyperaemias following arterial occlusion for 5‐40 s was dependent on the occlusion time. The peak changes in vascular conductance relative to the resting values were similar before and after administration of meclofenamic acid.5. Direct stimulation of the muscles of the hind limb with 0.5‐5 Hz produced frequency‐dependent increases in blood flow and oxygen uptake to the limb. Although these responses were depressed after meclofenamic acid, the relationship between blood flow and oxygen uptake was not changed. The responses to stimulation with 10 Hz were not affected by meclofenamic acid.6. An isolated chick rectum, superfused with re‐oxygenated venous blood from the hind limb during muscle stimulation at 10 Hz showed an initial relaxation, followed by contraction. The contraction was abolished after administration of meclofenamic acid.7. From these results it appears that the release of prostaglandins is not essential for hyperaemais associated with vessel occlusion, systemic hypoxia or muscle e

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. The sensitivity of human metacarpal veins and digital arteries obtained post‐mortem to noradrenaline and phenylephrine has been tested.2.pED50values for noradrenaline were significantly higher in the veins (699, s.e.m. = 008) than in the arteries (6.56, s.e.m. = 009), whereaspED50values for phenylephrine in the two tissues were not significantly different (arteries: 6.24, s.e.m. = 009; veins: 6.26, s.e.m. = 005).3. The addition of propranolol (4 × 10−6mol/l) alone, or in combination with hydrocortisone (4 × 10−5mol/l), did not affect the responses to either noradrenaline or phenylephrine. The further addition of cocaine (3 × 10−5mol/l) slightly shifted the noradrenaline and phenylephrine concentration‐effect curves to the left in both arteries and veins, but veins were still found to be more sensitive than arteries to noradrenaline whilst there was still no difference in the sensitivity of veins and arteries to phenylephrine.4. Cocaine also slightly potentiated responses to barium chloride, potassium chloride and serotonin.5. It is concluded that the difference in sensitivity to noradrenaline between arteries and veins cannot be explained by differences in neuronal uptake and it is possible that there may be differences in the properties of the postsynaptic α‐adrenoreceptors of the two tissues. It is also concluded that the potentiation of the contractile effect of noradrenaline produced by cocaine is not solely due to inhibition of neuronal u

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00055.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. Strips of bovine tracheal muscle and rabbit aorta produced sustained contractions on perfusion with Krebs solution made twice normal strength by addition of sucrose. The contractures were relaxed on return to normal Krebs solution.2. Similar contractures were produced by tracheal muscle strips in Krebs solutions made twice normal strength by addition of galactose, glucose or NaCl whereas urea caused only a transient contraction.3. In twice normal strength Krebs solution (sucrose added) the basal tension of rat portal vein and guinea‐pig taenia coli was increased. Spontaneous mechanical activity was maintained, but the frequency of contractions was reduced.4. The hypertonic contracture of bovine trachea in twice normal strength Krebs solution (sucrose added) was reduced by 15% by omission of Ca from the bathing fluid (01 mmol/1 EGTA added). Severe Ca depeletion, by prolonged washing in Ca‐free Krebs with 12.5 mmol/1 EGTA and Carbachol added, resulted in a 77% reduction in the hypertonic contracture.5. In twice normal Krebs solution (sucrose added), the hypertonic contracture was partially relaxed by isoprenaline (4 × 10−6mol/1); the contractile response to carbachol was reduced; the contractile response to high‐K Krebs solution was maintained.6. Atropine (5 × 10−7mol/1) abolished the contractile response to carbachol, but had no effect on the hypertonic contracture.7. It is suggested that the contraction of bovine tracheal strips in hypertonic solutions is mainly due to activation of the contractile myofilaments rather than simple cell shrinkage. Hypertonic solutions may also interfere with some steps in the excitation‐contraction coup

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00056.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. Tritiated digoxin was injected intravenously into euthyroid, hyperthyroid and hypothyroid rats. The rats were killed at intervals up to 24 h and tritium in serum and tissues counted.2. Serum concentrations of tritium in the hyperthyroid animals were less than in the control group, whereas the concentrations in the hypothyroid group were similar to those in the control group.3. Cardiac tissue concentrations of tritium were higher in the hyperthyroid group than in the control group, but in the hypothyroid group were similar to the control group.4. The decreased serum levels in the hyperthyroid rats were probably due to an increased volume of distribution.5. Pharmacological resistance to digoxin in hyperthyroidism must be due to some alteration in cardiac function and it is suggested that this is an increase in Na/K ATPase receptors.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00057.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. In Sprague‐Dawley rats, two‐kidney, one‐clip renal hypertension was induced, and the drinking behaviour as well as total fluid and sodium intake were studied before and for 16 days after the operation.2. When water alone was offered as drinking fluid, the blood pressure reached values that were by about 20 mmHg higher than those in the rats which had free choice of drinking water or 2% saline.3. In those rats which had water and 2% saline to drink, the total sodium and fluid intake rose transiently for three days, as compared with that of the sham‐operated controls, and increased steeply starting from the 7th and 10th day, respectively. When a tighter stenosis of the renal artery was induced, the pressure rose more rapidly, and the total fluid and sodium intake increased continuously after the operation until the end of the experiment.4. A positive correlation was demonstrable between the height of blood pressure and the total daily intake of fluid and sodium, respectively.5. The relation between the total daily fluid and the total daily sodium intake followed a straight regression line.6. The hypertensive rats which had a high total sodium intake responded to the withdrawal of the 2% saline solution, within 2 days, with increased water intake, decreased food intake, and loss of body weight, whereas the blood pressure remained high.7. In the two‐kidney, one‐clip hypertension, no ‘critical level of blood pressure’ can be defined, beyond which the contralateral kidney starts

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00058.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. The haemodynamic responses to progressive increments in positive end‐expiratory pressure ventilation (PEEP) were assessed in dogs in the presence and absence of pericardial effusion (2‐2 ml saline/kg).2. Increasing levels of PEEP (0, 4, 8, 16 cm H2O) were associated with increases in right atrial, left atrial, pericardial and pulmonary artery diastolic pressure; increases in pulmonary vascular resistance; decreases in aortic blood pressure; and decreases in cardiac index or stroke index.3. Pericardial effusion that was associated with an increase in pericardial pressure of 3 mmHg was not associated with significant changes in aortic blood pressure or stroke index. In contrast 8 cm PEEP was associated with significant decreases in both these haemodynamic variables yet pericardial pressure increased only 2‐2 mmHg.4. For these levels of PEEP and pericardial effusion, the same haemodynamic response to PEEP was observed regardless of the presence or the absence of pericardial effusion.5. Similar changes in aortic blood pressure and stroke index despite different pericardial pressures is reflected by significantly different intercepts in the linear model relating these haemodynamic variables to pericardial pressure in the presence and absence of pericardial effusion.6. The results suggest that these haemodynamic consequences of PEEP are primarily a function of pulmonary hyperinflation and are less dependent on increases in extracardiac pressurep

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00059.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY1. The effects of adenosine and adenine nucleotides were studied on arterial vasculature in blood‐perfused arterial preparations of dogs which were isolated from the internal and external carotid arteries. Each compound was administered directly into the cannulated artery over a period of 4 s.2. In both arterial preparations, adenosine produced a dose‐related vasodilatation and was more potent than AMP. On the other hand, ATP produced a dose‐related vasoconstriction and was more potent tha

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1980.tb00060.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY