Summary
Our previous studies of angiotension-induced acute hypertension showed increased intracerebral arteriolar permeability associated with markedly enhanced pinocytosis. This study was performed to determine whether similar findings occurred in spontaneous non-pharmacologically induced chronic hypertension.
Cerebrovascular permeability to horseradish peroxidase (HRP) was studied over an 82-week period in spontaneously hypertensive rats (SHR) derived from a strain that originated from Japan. In a few animals increased cerebrovascular permeability to HRP was observed, associated with enhanced pinocytosis. Quantitatively, the number of pinocytotic vesicles in permeable arteriolar segments was significantly increased suggesting that enhanced pinocytosis is the principal mechanism of early cerebrovascular changes in SHR.
Light microscopy of renal, ocular and cerebral vessels revealed medial hyperplasia affecting renal vessels at 16 weeks and occurring later in ocular and cerebral vessels. Deposition of fibrin in renal vessels was observed from 64 weeks onwards but was not associated with renal failure.
Similar content being viewed by others
References
Amano S (1977) Vascular changes in the brain of spontaneously hypertensive rats. Hyaline and fibrinoid degeneration. J Pathol 121: 119–128
Beggs JL, Waggener JD (1979) The acute microvascular responses to spinal cord injury. In: Thompson RA, Green JR (eds) Advances in neurology, vol 22. Raven Press, New York, pp 179–189
Folkow B, Hällback M (1977) Physiopathology of spontaneous hypertension in rats. In: Genest J, Koiw E, Kuchel O (eds) Hypertension. Physiopathology and treatment. McGraw-Hill, New York, pp 507–529
Hazama F, Amano S, Haebara H, Okamoto K (1975a) Changes in vascular permeability in the brain of stroke-prone spontaneously hypertensive rats studied with peroxidase as a tracer. Acta Pathol Jpn 25: 565–574
Hazama F, Ooshima A, Tanaka T, Tomimoto K, Okamoto K (1975b) Vascular lesions in the various substrains of spontaneously hypertensive rats and the effects of chronic salt ingestion. Jpn Circ J 39: 7–22
Hazama F, Amano S, Haebara H, Yamori Y, Okamoto K (1976) Pathology and pathogenesis of cerebrovascular lesions in spontaneously hypertensive rats. In: Cervós-Navarro J, Betz E, Matakas F, Wüllenweber R (eds) The cerebral vessel wall. Raven Press, New York, pp 245–252
Hedley-Whyte ET, Lorenzo AV, Hsu DW (1977) Protein transport across cerebral vessels during metrazole-induced convulsions. Am J Physiol 233: C74-C85
Limas C, Westrum B, Limas CJ (1980) The evolution of vascular changes in the spontaneously hypertensive rat. Am J Pathol 98: 357–384
Loosinsky AS, Garcia JH, Iwanowski L, Lightfoote WE jr (1979) New ultrastructural evidence for a protein transport system in endothelial cells of gerbil brains. Acta Neuropathol (Berl) 47: 105–110
Manz HJ, Robertson DM (1972) Vascular permeability to horseradish peroxidase in brainstem lesions of thiamine-deficient rats. Am J Pathol 66: 565–576
Nag S, Robertson DM, Dinsdale HB (1977) Cerebral cortical changes in acute experimental hypertension. An ultrastructural study. Lab Invest 36: 150–161
Nag S, Robertson DM, Dinsdale HB (1979) Quantitative estimate of pinocytosis in experimental acute hypertension. Acta Neuropathol (Berl) 46: 107–116
Okamoto K (1969) Spontaneous hypertension in rats. Int Rev Exp Pathol 7: 227–270
Okamoto K, Aoki K (1963) Development of a strain of spontaneously hypertensive rats. Jpn Circ J 27: 282
Petito CK, Schaefer JA, Plum F (1976) The blood-brain barrier in experimental seizures. In: Pappius HM, Feindel W (eds) Dynamics of brain edema. Springer, Berlin Heidelberg New York, pp 38–42
Reese TS, Karnovsky MJ (1967) Fine structural localisation of blood-brain barrier to exogenous peroxidase. J Cell Biol 34: 207–217
Simionescu N, Simionescu M, Palade GE (1975) Permeability of muscle capillaries to small heme-peptides. Evidence for the existence of patent transendothelial channels. J Cell Biol 64: 586–607
Sokabe H (1965) Renin-angiotensin system in the spontaneously hypertensive rat. Nature 205: 90
Spiro D, Lattes RG, Wiener J (1965) Cellular pathology of experimental hypertension. I. Hyperplastic arteriolar sclerosis. Am J Pathol 47: 19–49
Westergaard E (1977) The blood-brain barrier to horseradish peroxidase under normal and experimental conditions. Acta Neuropathol (Berl) 39: 181–187
Wiener J, Spiro D, Lattes RG (1965) Cellular pathology of experimental hypertension. II. Arteriolar hyalinosis and fibrinoid change. Am J Pathol 47: 457–485
Author information
Authors and Affiliations
Additional information
This work was supported by the Medical Research Council of Canada, Grant No. MT 1647
Rights and permissions
About this article
Cite this article
Nag, S., Robertson, D.M. & Dinsdale, H.B. Morphological changes in spontaneously hypertensive rats. Acta Neuropathol 52, 27–34 (1980). https://doi.org/10.1007/BF00687225
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00687225