Chronic, Severe Hypertension Does Not Impair Spatial Learning and Memory in Sprague-Dawley Rats

Abstract

This study tested the hypothesis that long-term hypertension impairs spatial learning and memory in rats. In 6-wk-old Sprague-Dawley rats, chronic hypertension was induced by placing one of three sizes of stainless steel clips around the descending aorta (above the renal artery), resulting in a 20-80-mm Hg increase of arterial pressure in all arteries above the clip, that is, the upper trunk and head. Ten months later, the rats were tested for 5 d in a repeated-acquisition water maze task, and on the fifth day, they were tested in a probe trial; that is, there was no escape platform present. At the end of the testing period, the nonsurgical and sham control groups had similar final escape latencies (16 ± 4 sec and 23 ± 9 sec, respectively) that were not significantly different from those of the three hypertensive groups. Rats with mild hypertension (140-160 mm Hg) had a final escape latency of 25 ± 6 sec, whereas severely hypertensive rats (170-199 mm Hg) had a final escape latency of 21 ± 7 sec and extremely hypertensive rats (>200 Hg) had a final escape latency of 19 ± 5 sec. All five groups also displayed a similar preference for the correct quadrant in the probe trial. Together, these data suggest that sustained, severe hypertension for over 10 mo is not sufficient to impair spatial learning and memory deficits in otherwise normal rats.

Exercise intensities modulate cognitive function in spontaneously hypertensive rats through oxidative mediated synaptic plasticity in hippocampus

“…Furthermore, our results demonstrated that the SHR did not exhibit impaired learning in the water maze task, which is different to the findings reported in previous animal and clinical studies which indicated that chronic hypertension could impair learning and memory. Indeed, our results were consistent with the findings of Kadish et al 35 showing that learning impairment of SHR might not be entirely explained by hypertension. Finally, exercise improves cognitive function and causes structural and biochemical adaptation via modulating ROS‐synaptophysin pathways.…”

Antihypertensive and cognitive effects of grape polyphenols in estrogen-depleted, female, spontaneously hypertensive rats

“…Together this suggests that hypertension per se can decrease learning in rats. However, our recent studies show that in Sprague-Dawley rats, chronic, severe hypertension (aortic coarctation) for 12 mo has no significant effect on spatial learning (16). Treatment of aging normotensive rats with angiotensinconverting enzyme inhibitors improves memory despite negligible effects on arterial pressure (39), and chronic antihypertensive treatment of SHR with hydralazine does not improve their age-related memory impairment (39).…”

Intramyocardial Injection of Human Adipose-Derived Stem Cells Ameliorates Cognitive Deficit By Regulating Oxidative Stress-Mediated Hippocampal Damage After Myocardial Infarction

“…The nitro blue tetrazolium reaction in TRIS-buffer was used to determine the plasma superoxide level [28]. As the reduction can be inhibited by superoxide dismutase, this reaction is speci c for superoxide radicals [29]. All measurements were performed at a wavelength of 530 nm.…”