In spontaneously hypertensive rats, a standard model of vascular cognitive impairment, hypertension reduced blood flow in the hippocampus (CA1) and medial prefrontal cortex, with more widespread hypoperfusion in females than males. The mineralocorticoid receptor blocker eplerenone restored perfusion in both regions in females and improved spatial working memory, but did not rescue hippocampus-dependent long-term memory. Males showed no benefit from the drug, pointing to a sex-specific, MR-dependent mechanism of hypertension-related cognitive decline. This evidence comes from rats, not humans. Eplerenone is already prescribed for heart failure and resistant hypertension, so a brain-protective role for MR blockade is a plausible, testable idea, and the sex split is the notable part: trials of blood-pressure drugs for dementia prevention rarely stratify by sex, and a mechanism that works in only one sex could be diluted in pooled analyses. Still, caution is warranted. Rat findings often fail to translate, the hypertensive model does not capture decades of human vascular aging, and the dissociation between rescued working memory and unrescued long-term memory suggests that restoring blood flow alone may not repair every cognitive domain. Nothing here supports adults taking eplerenone to protect memory; the practical message remains controlling blood pressure. This is a preprint that has not been peer reviewed, so its conclusions may change. As an editorial assessment, the work is incremental but useful for generating hypotheses about sex-specific dementia prevention.