摘要:

The renal tissue of 12-, 29-, 90- and 165-day-old genetically obese, hyperphagic, diabetic KKAy and age-matched nondiabetic C57BL/6 mice was morphometrically analyzed to characterize the development of peripheral glomerular capillary basement membrane thickening in the kidney of this animal model. Peripheral glomerular basement membrane (GBM) thickness was unremarkable in KKAy mice at 12 days of age (prior to onset of hyperinsulinemia) or at 29 days of age (after development of hyperinsulinemia). By 90 days of age, when the KKAy mice became severely hyperinsulinemic and hyperglycemic, the peripheral GBM thickness was greater (13%, p < 0.002) in the diabetic compared with the nondiabetic mice. Furthermore, the peripheral GBM thickness was exacerbated (20%, p < 0.001) by 165 days of age in the KKAy mice. The results of the present study suggest that peripheral glomerular capillary basement membrane thickening has an early onset and develops rapidly in the KKAy mouse in comparison with other diabetic animal models. Therefore, the KKAy mouse seems to be an appropriate model for further investigation of early structural and functional defects in the glomerular filtration barrier.

ISSN:1018-1172    

DOI:10.1159/000158706

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Lymphatic valves assure the forward propulsion of fluid along the lymphatic vessels. A description of valve function in skeletal muscle must be based on a knowledge of the valve morphology. To this end, histological sections of valves from lymphatic microvessels of the rat spinotrapezius muscle were examined with light microscopy. All of the approximately 50 valves studied from 20 rats had a bileaflet structure, with a buttress formed at each side of the valve by the fusion of opposing leaflets. This valve structure would allow the valve to close without inversion. There is no evidence for active smooth muscle action to open and close the valve. Since the Reynolds number of lymph flow is very small (about 0.0025), only pressure and viscous forces are available for valve closure. A particular mechanism based on the actual lymphatic valve structure is proposed.

ISSN:1018-1172    

DOI:10.1159/000158707

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The biosynthesis of collagen and elastin was followed during the development of spontaneous hypertension in rats (SHR) of the Okamoto-Aoki strain. Strain-matched animals of the same age, which did not develop hypertension, served as controls. Both collagen and elastin synthesis (as revealed by specific hydroxyproline activity) was found to exceed control levels in the prehypertensive period, to decrease during the development of hypertension and to increase again in the period of the established hypertensive state. From the two main collagen types present, synthesis of collagen type III exceeded that of type I in the prehypertensive period (at the age of 4 weeks) and this relation was reversed during the period of established hypertension. It is suggested that (a) the vascular connective tissue metabolism in SHR differs from that in strain-matched controls, and (b) the reverse rate of collagen type IIIto collagen type I synthesis during hypertension development may be considered an adaptive response to the increasing pressure load which may alter the mechanical properties of the vessel wall.

ISSN:1018-1172    

DOI:10.1159/000158708

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Furosemide-induced inhibition of 86Rb uptake was measured in rat and rabbit aorta and compared with its ability to inhibit contractions induced by α-adrenergic agonists. In both rat and rabbit tissues, furosemide defined a portion of 86Rb uptake (IC50 = 2.5 µM) which was distinct from the ouabain-sensitivite fraction. Furosemide-sensitive 86Rb uptake was [Cl–]ext dependent and required Na+ and K+ for optimal activity, suggesting that it reflected a Na+-K+ cotransport process. Furosemide-sensitive 86Rb uptake was found to be greater in HEPES buffer than in bicarbonate buffer. Phenylephrine-induced contractions of rat and rabbit aorta were inhibited by furosemide; however, rat responses were far more sensitive. Agonist-induced uptake of 45Ca was reduced by furosemide in rat aorta, but not in rabbit aorta. Agonist-induced 45Ca efflux stimulation was reduced in both species. These findings indicate the presence in arteries of a furosemide-sensitive, Cl– dependent Na+-K+ cotransport process. Along with other monovalent transport processes, it may modulate Ca2+ availability and thereby influence arterial contract

ISSN:1018-1172    

DOI:10.1159/000158709

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Adrenergic innervation in the main trunk of the mesenteric artery was studied in stroke-prone spontaneously hypertensive rats (SHRSP) as well as in a new strain of SHRSP (M-SHRSP) and was compared with that of normotensive Wistar Kyoto rats (WKY). Noradrenaline (NA) content and high K-induced NA release in the artery of 6-week-old SHRSP and M-SHRSP were greater than those in the artery of WKY. These results suggest that a higher adrenergic innervation of the artery might be involved in the development of hypertension in SHRSP and M-SHRSP.

ISSN:1018-1172    

DOI:10.1159/000158710

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158711

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158712

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158713

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158705

出版商:S. Karger AG    

年代:1987

数据来源: Karger