Search Results - (Author, Cooperation:R. C. Webb)

2016-01-19

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

*Absorbable Implants/adverse effects ; Administration, Cutaneous ; Animals ; Body Temperature ; Brain/*metabolism/surgery ; Electronics/*instrumentation ; Equipment Design ; Hydrolysis ; Male ; Monitoring, Physiologic/adverse effects/*instrumentation ; Organ Specificity ; Pressure ; *Prostheses and Implants/adverse effects ; Rats ; Rats, Inbred Lew ; *Silicon ; Telemetry/instrumentation ; Wireless Technology/instrumentation

2018-03-06

The American Society for Pharmacology and Experimental Therapeutics

0022-3565

1521-0103

Medicine

1420-9071

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary Ouabain inhibits the relaxing effect of Ca2+ (but not of Mn2+) on contractile responses in tail artery strips isolated from spontaneously hypertensive and normotensive rats. The magnitude of ouabain inhibition was greater in vascular strips from hypertensive rats suggesting a significant difference in basic membrane function in hypertensive vascular smooth muscle.

Electronic Resource

1432-0428

Key words Endothelium, acetylcholine, angiotensin converting enzyme inhibitor, vascular smooth muscle.

Springer Online Journal Archives 1860-2000

Medicine

Summary This study investigated the protective effect of the angiotensin converting enzyme inhibitor, ramipril, on endothelium-dependent responses in arteries from control (CON) and streptozotocin-induced (STZ) diabetic rats. Three hypotheses were tested: 1) there is an endothelium-dependent component to the increased alpha-adrenergic responsiveness characteristic of diabetes; 2) endothelium-dependent, acetylcholine-induced relaxation is attenuated in aorta from diabetic rats; and 3) ramipril (3 mg/kg daily in the food, 12–15 weeks) will prevent functional vascular changes in diabetic rats. Vascular function was assessed in aortic rings using standard muscle bath procedures for measurement of isometric force. Sensitivity to phenylephrine was increased in aortic rings from diabetic compared to control values [pD2 values (-log ED50): CON =6.22±0.12, STZ =7.54±0.11), and removal of the endothelium (-Endo) increased phenylephrine sensitivity (CON-Endo =7.40±0.11, STZ-Endo =8.32± 0.18). The magnitude of the shift in responsiveness following endothelium removal was greatest in control rats. Ramipril treatment (Ram) partially normalized phenylephrine responsiveness in intact (STZ+Ram = 6.55±0.11) and denuded (STZ-Endo+Ram =7.75± 0.10) vessels. Vasodilatation to acetylcholine and nitroglycerin was not altered in diabetic rats nor was it affected by ramipril treatment. Diabetes increases contractile sensitivity to phenylephrine but not to vasodilators and chronic ramipril treatment prevents this increase in contractile sensitivity. Ramipril treatment did not alter the hyperglycaemic condition induced by streptozotocin. The changes in phenylephrine sensitivity appear to involve an endothelial and a smooth muscle component. [Diabetologia (1994) 37: 664–670]

Electronic Resource

1432-0428

Endothelium ; acetylcholine ; angiotensin ; converting enzyme inhibitor ; vascular smooth muscle

Springer Online Journal Archives 1860-2000

Medicine

Summary This study investigated the protective effect of the angiotensin converting enzyme inhibitor, ramipril, on endothelium-dependent responses in arteries from control (CON) and streptozotocin-induced (STZ) diabetic rats. Three hypotheses were tested: 1) there is an endothelium-dependent component to the increased alpha-adrenergic responsiveness characteristic of diabetes; 2) endothelium-dependent, acetylcholine-induced relaxation is attenuated in aorta from diabetic rats; and 3) ramipril (3 mg/kg daily in the food, 12–15 weeks) will prevent functional vascular changes in diabetic rats. Vascular function was assessed in aortic rings using standard muscle bath procedures for measurement of isometric force. Sensitivity to phenylephrine was increased in aortic rings from diabetic compared to control values [pD2 values (-log ED50): CON=6.22±0.12, STZ=7.54±0.11), and removal of the endothelium (-Endo) increased phenylephrine sensitivity (CON-Endo=7.40±0.11, STZ-Endo=8.32±0.18). The magnitude of the shift in responsiveness following endothelium removal was greatest in control rats. Ramipril treatment (Ram) partially normalized phenylephrine responsiveness in intact (STZ + Ram=6.55±0.11) and denuded (STZ-Endo + Ram=7.75±0.10) vessels. Vasodilatation to acetylcholine and nitroglycerin was not altered in diabetic rats nor was it affected by ramipril treatment. Diabetes increases contractile sensitivity to phenylephrine but not to vasodilators and chronic ramipril treatment prevents this increase in contractile sensitivity. Ramipril treatment did not alter the hyperglycaemic condition induced by streptozotocin. The changes in phenylephrine sensitivity appear to involve an endothelial and a smooth muscle component.

Electronic Resource

1420-908X

Springer Online Journal Archives 1860-2000

Medicine

Abstract The effect of complement fragments on coronary blood flowin vivo and the contraction of coronary arteriesin vitro was determined. In pentobarbital anesthetized dogs, intraarterial bolus injection of C3a and C5a, zymosan-activated serum and methylcholine in the coronary vascular bed caused transient and dose-dependent increases in coronary blood flow. Similar increases were obtained with 25 μg of C3a (104±13%,n=5) and 0.1 μg of methylcholine (102±4%,n=3). Smaller, increases in blood flow were elicited by 25 μg of C5a (41±18%,n=4) and 0.2 ml, of zymosan-activated serum (48±5%,n=4). None of these responses were associated, with significant changes in left ventricular contractile force measured with a strain gauge, arterial blood pressure, and heart rate. C3a dilated the coronary vascular bed in conscious dogs with an activity equal to or greater than that observed in anesthetized dogs. Isolated canine coronary arteries that were precontracted with serotonin relaxed in response to C3a, whether or not the endothelium was intact. Overall these data suggest that physiologically high doses of anaphylactic complement fragments vasodilate the canine coronary circulation.

Electronic Resource

1420-9071

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary Reactive hyperemia was induced in hindlimbs of rats by occlusion of the femoral artery. Using fluorescein dye as a peripheral vascular marker, we observed that there was an increase in the number of flowing capillaries supplying the muscle fibres following release of the occlusion. The results indicate that the number of flowing capillaries is not dependent on the duration of occlusion (2–10 min).

Electronic Resource