摘要:

SUMMARY1. The effects of ouabain and acetazolamide on the secretion of pancreatic juice stimulated by secretin in anaesthetized dogs were investigated.2. Intra‐arterial injection of ouabain (1–10 μg) and acetazolamide (1–10 mg) caused dose‐dependent decreases in the volume of pancreatic juice. When both drugs were added together, the inhibitory effects were significantly higher than for each drug alone.3. The bicarbonate concentration in the pancreatic juice was decreased and the chloride concentration was increased by ouabain and acetazolamide, but sodium and protein concentrations were not modified.4. The results suggest that the Na+K+‐ATPase and carbonic anhydrase activities play important roles in water and electrolyte secretion, and that ouabain and acetazolamide inhibit secretin‐stimulated pancreatic secretion by acting on different systems in the exocrine c

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01538.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. We studied whether or not circulating catecholamines of adrenal origin play a major role in cardiovascular responses evoked by bilateral carotid artery occlusion (3 min) in anaesthetized dogs.2. In the control group, the following parameters increased significantly (P<0.05) during bilateral carotid occlusion: aortic systolic pressure, heart rate, net adrenal catecholamine output, net renal noradrenaline output, and plasma catecholamine concentrations in aortic blood. Similar responses were obtained during the second occlusion performed approximately 25 min after the first occlusion.3. After functional adrenalectomy (ADRX: diversion of adrenal venous blood flow), the increase in aortic adrenaline concentration observed during bilateral carotid occlusion was abolished. The increase in aortic noradrenaline concentration during the occlusion was significantly attenuated by approximately 60% (P<0.01) after ADRX.4. The increase in net renal noradrenaline output during bilateral carotid occlusion after ADRX was not different from that observed before ADRX. Similarly, the response of aortic systolic pressure and heart rate during the occlusion was unaffected by ADRX. Furthermore, the increase in net adrenal catecholamine output during the occlusion was not affected by ADRX itself.5. From these results, we conclude that the increase in circulating catecholamines of adrenal origin during bilateral carotid occlusion is not a major determinant for the increases in aortic pressure and heart rate. The results suggest that these cardiovascular responses during the occlusion are mediated principally by neuronal noradrenaline released from peripheral sympathetic nerve terminals.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01539.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. Perfusion pressure was measured in thein situmesentery of anaesthetized rats perfused with blood at a constant 2 mL/min.2. Increases in perfusion pressure were produced by mesenteric peri‐arterial nerve stimulation at 10 Hz for 5 s at 2 min intervals and by bolus intra‐arterial injections of the vasoconstrictors noradrenaline, angiotensin II and 5‐hydroxytryptamine.3. The intra‐arterial infusion of platelet‐activating factor (PAF) to produce a blood concentration of 3 × 10−10mol/L inhibited all responses to a similar extent. Intra‐arterial prazosin (1–5 × 10−9mol/L), however, preferentially reduced responses to nerve stimulation and noradrenaline.4. PAF at concentrations from 3 × 10−11to 10−9mol/L produced increasing inhibition of vasoconstrictor responses to nerve stimulation. The dose‐response to PAF was shifted to the right by the concomitant intra‐arterial infusion of the PAF antagonist SRI 63–441.5. PAF at very low concentrationsin vivoinhibits mesenteric vasoconstriction, produced by sympathetic nerve stimulation or various agonists, by a PAF‐receptor mediated vasodilatati

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01540.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The effects, on parturition in the rat, of subacute and acute opioid administration were studied. Further experiments investigated the role of modulation of maternal plasma and pituitary oxytocin (OXY) and arginine vasopressin (AVP) levels in these effects.2. Subacute opioid (M320, buaprenorphine or bremazocine) administration prolonged the gestation of rats. This was accompanied by toxic effects on the offspring. Acute subcutaneous (s.c.) M320 (10 μg/kg) administration was accompanied by prolonged gestation without toxic effects.3. Subacute M320 (10 μg/kg, s.c., twice daily) treatment was accompanied by increased interbirth intervals in parturient rats.4. Maternal OXY but not AVP release, as assessed by measurement of plasma and pituitary immunoreactivity, was elevated during and up to 1 h after the completion of parturition. Subacute M320 treatment did not inhibit this elevated OXY releas

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01541.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. A rapid imaging technique with temporal resolution of about 1 ms was employed to describe cell‐length changes during the isotonic contraction cycle of adult rat ventricular myocytes at 22°C.2. Parameters of cell contraction and relaxation were defined and values obtained under control conditions and after treatment with 5 μmol/L verapamil.3. Over 15 min, verapamil dramatically reduced the maximum shortening attained. This was associated with delay in both excitation‐contraction coupling latency and the time at which maximum rate of shortening occurred. However, peak shortening was recorded earlier in the contraction cycle. Total cell‐cycle time was abbreviated under the influence of verapamil and maximum rates of shortening and lengthening were depressed in a similar manner.4. The results highlight the value of improved temporal precision in describing myocyte contractility and validate the use of the parameters defined in the single‐cell model for the study of the mechanisms of action of cardioton

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01542.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. Both natriuretic and hypotensive effects of brain natriuretic peptide (BNP), a novel peptide identified in porcine brain, were investigated in anaesthetized DOCA‐salt rats and control rats.2. An intravenous injection of two different doses (0.5 and 5.0 nmol/kg) of BNP produced a rapid and marked natriuresis and hypotension in DOCA‐salt rats.3. In particular, significant differences of responsiveness were observed between DOCA‐salt and control rats when administered the lower dose of BNP.4. It was suggested that DOCA‐salt rats might be relatively more susceptible

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01543.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The effects of μ‐ and K‐opiate receptor agonists on plasma concentrations of immunoreactive (ir) oxytocin (OXY) and arginine vasopressin (AVP) in normally hydrated and water‐deprived rats were studied.2. Water‐deprivation for 36 h elevated both plasma ir‐OXY and ir‐AVP concentrations of Long‐Evans rats. These elevated levels were lowered in a dose‐dependent manner after subcutaneous administration of bremazocine (3–10 μg/kg), M320 (10–100 μg/kg) or morphine (0.1–10 mg/kg). Comparable reductions of plasma concentrations of ir‐AVP and ir‐OXY were observed.3. Plasma concentrations of ir‐OXY and ir‐AVP of normally hydrated Long‐Evans rats were lower after subcutaneous administration of bremazocine (10 μg/kg), M320 (10 μg/kg) and morphine (1.0 mg/kg).4. These data suggest that both μ‐ and K‐opiate receptor agonists inhibit both OXY and AVP

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01544.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The effects of dibutyryl cyclic AMP (cAMP), isoproterenol and colforsin (forskolin) were evaluated on respiratory burst in human polymorphonuclear neutrophils (PMN).2. Dibutyryl cAMP showed a dose‐dependent inhibition ofn‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP)‐induced superoxide production by human PMN.3. Administration of isoproterenol induced a dose‐dependent inhibition of FMLP‐induced superoxide production by human PMN, and the inhibition was blocked by propranolol.4. Administration of colforsin induced a dose‐dependent inhibition of FMLP‐induced superoxide production by human PMN, and the inhibition could not be blocked by propranolol.5. Incubation with colforsin caused a significant increase in the cAMP level in human PMN.6. Pretreatment with colforsin caused a dose‐dependent inhibition in the elevation of intracellular free calcium (monitored by fura‐2 fluorescence), which was observed in human PMN stimulated with FMLP.7. These results suggest that cAMP is an inhibitory factor of superoxide production and intracellular calcium mobilization in human P

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01545.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. This study examined the hypothesis that inhibition of Na, K ATPase with digoxin would enhance the pressor response to aldosterone infusion in conscious sheep.2. While intravenous infusion of digoxin (10 μg/kg per day for 5 days) had no effect on blood pressure and aldosterone infusion (6 μg/kg per day for 5 days) increased blood pressure by 7 mmHg, combined infusion of digoxin and aldosterone increased blood pressure by 17 mmHg.3. The metabolic effects of the combined digoxin and aldosterone infusion were similar to those for aldosterone alone, suggesting that digoxin did not enhance the mineralocorticoid action of aldosterone.4. The results of this study suggest that changes in Na influx (aldosterone‐dependent) and efflux (digoxin‐dependent) are important in the genesis of aldosterone‐induced hyper

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01546.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY