Impaired learning and memory in mature spontaneously hypertensive rats.
In very old, normotensive rats, a disorganization occurs selectively in the retrosplenial cortex, and a similar disorganization occurs in this area in spontaneously hypertensive rats (SHR) at a much earlier age. Since this breakdown compromises a neural circuit involved in learning and memory, this study tests the hypotheses that these functions are disturbed in mature SHR and that they can be prevented or attenuated by long-term, anti-hypertensive therapy. SHR and Sprague Dawley rats (SD) at 3- and 12 months of age, and a group of SHR that had been normotensive from 3 to 12 months of age (CAP-SHR) were trained on an 8 arm radial maze task. Of the 12-month-old groups, SD reached criterion earliest (28 +/- 2 days) and made the least number of total errors. In comparison, 12-month-old SHR took significantly longer to reach criterion (39 +/- 2 days) and made nearly twice as many total errors. CAP-SHR were intermediate between the other two groups (32 +/- 2 days). Three-month-old SD learned the task at the same rate as the 12-month-old SD. In contrast, 3-month-old SHR learned the task significantly faster (21 +/- 1 days) and with fewer errors than any other group. These data indicate that, in SHR, learning and memory are compromised by 12 months of age, and that anti-hypertensive therapy with captopril partially prevents this decline.
Wyss
J M
JM
Department of Cell Biology, University of Alabama, Birmingham 35294.
Fisk
G
G
van Groen
T
T
D000818:Animals; D002216:Captopril / Q000494:pharmacology; D006973:Hypertension / Q000503:physiopathology* / Q000523:psychology; D007858:Learning / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D012153:Retention, Psychology / Q000187:drug effects
D002216:Captopril