BRAIN KALLIKREIN-KININ SYSTEM ABNORMALITIES IN SPONTANEOUSLY HYPERTENSIVE RATS

The objective of the present study was to determine whether the brain kallikrein-kinin system differs between spontaneously hypertensive rat s (SHR) and normotensive Wistar-Kyoto rats (WKY) and if so, whether an y detected differences occur before the development of hypertension in SHR. We measured cerebrospinal fluid levels of various components of the system in adult and young prehypertensive SHR and WKY. Cerebrospin al fluid kinin concentration and appearance rate were higher in SHR. C erebrospinal fluid active kallikrein level and kininogenase activity w ere also higher in adult SHR. In addition, cerebrospinal fluid kinin c oncentration and appearance rate were higher in prehypertensive, 5- to 6-week-old SHR compared with age-matched WKY. However, no differences s in cerebrospinal fluid kallikrein or kininogenase activity were obse rved between the two strains of young rats. Cerebrospinal fluid kinin concentration was higher in young versus adult rats of the same strain . In WKY, cerebrospinal fluid kallikrein also decreased with age altho ugh cerebrospinal fluid kallikrein concentration did not decrease in y oung and adult SHR. Together, these data suggest that there is a hyper active kallikrein-kinin system in the brain of SHR that may contribute to the hypertensive state in this animal model.