Abstract
With constriction of left renal arteries of 193 rats in different degrees and either extirpation or infarction of right kindeys, four different elevation patterns of blood pressure were followed.
(1) Macro- and microscopically, these rats developed 6 different cerebrovascular lesions as follows; single massive cerebral hemorrhage, multiple punctate hemorrhage, microscopic hemorrhage, fibrinoid necrosis, cerebral softening and plasmatic imbibition.
(2) Rats which developed single massive hemorrhage died unexpectedly in the early stage of experiment with moderate degree of constriction, while those which developed multiple punctate hemorrhage became temporarily hyperirritable.
(3) Single massive hemorrhage, multiple punctate hemorrhage and fibrinoid necrosis were found almost exclusively in the cerebral cortical area, while 30-40% of microscopic hemorrhage, cerebral softening and plasmatic imbibition were also found in the basal ganglia.
(4) Loosely constricted groups with low rate of increase and also low maximum of blood pressure showed high incidences of microscopic hemorrhage, plasmatic imbibition and cerebral softening and none of macroscopic hemorrhage or fibrinoid necrosis. Moderately constricted groups with both a high rate of increase and also a high maximum of blood pressure developed more single massive cerebral hemorrhage than multiple punctate hemorrhage and fibrinoid necrosis and cerebral softening in about half of the cases but few of microscopic hemorrhage and plasmatic imbibition. Severely constricted groups and group of contralateral renal infarc-tion caused more multiple punctate hemorrhage than single massive hemorrhage and the latter of which showed fibrinoid necrosis, cerebral softening and microscopic hemorrhage in about half of the cases.
(5) Microscopic hemorrhage and plasmatic imbibition were maximal in appearances at the moderate degree of hypertension and subsided abruptly later on, while cerebral softening and multiple punctate hemorrhage were the more frequent as the blood pressure rose higher. Fibrinoid necrosis and single massive hemorrhage showed their peak appearances around the time when the rate of increase of blood pressure was maximal.
In summary, there are three types of cerebral hemorrhage in Goldblatt type hypertensive rats and they seemed to be pathogenetically different each other.
