Se estudió el posible efecto protector de drogas antihipertensivas sobre el deterioro de la memoria de reconocimiento espacial (MRE) en ratas espontáneamente hipertensas (SHR). Desde las 12 semanas de vida, las SHR fueron tratadas, a través del agua de bebida, con Losartan (SHR-L, 30mg/kg/día, n=13) ó Hidralazina (SHR-H, 11mg/kg/día, n=13), permaneciendo un tercer grupo no tratado (SHR-C, n=13). Al año de tratamiento se determinó la presión arterial (PA) sistólica y los animales fueron evaluados en el Laberinto en Cruz Elevado (LCE), el Campo Abierto (CA), y el laberinto en forma de Y. Resultados: los grupos SHR-L y SHR-H tuvieron valores de PA (147.9±8.1 y 139.3±10.6 mmHg) significativamente menores al grupo SHR-C (211.6±11.9 mmHg, P<0.01 para ambas comparaciones), no diferenciándose entre sí. Las SHR-L y SHR-H mostraron preservada su MRE, con un porcentaje de entradas en el brazo novedoso, durante el ensayo de retención, significativamente mayor al de los demás brazos (P<0.05 y P<0.01). Este resultado no puede atribuirse al efecto de los drogas sobre otras variables, ya que los grupos no se diferenciaron en sus niveles de locomoción (CA) ó ansiedad (LCE). Se concluye que el tratamiento crónico con Losartan ó Hidralazina previene el deterioro de la MRE en SHR. Palabras clave SHR Losatan Hidralazina Memoria ABSTRACT CHRONIC TREATMENT WITH LOSARTAN OR HYDRALAZINE PROTECTS FROM THE WORSENING OF SPATIAL RECOGNITION MEMORY IN ADULT SHR The possible protection effect of anti-hypertensive drugs on spatial recognition memory (SRM) in spontaneously hypertensive rats (SHR) was studied. Twelve-weeks-old male SHRs were divided into 3 groups: those that were not treated (SHR-C, n=13), and those receiving Losartan (SHR-L, 30mg/kg/día, n=13) or Hydralazine (SHR-H, 11mg/kg/día, n=13) through the drinking water. At one year of treatment the systolic blood pressure (BP) was measure and the rats were tested in the Elevated Plus Maze (EPM), the Open Field Test (OF), and the Y-maze. Results: the SHR-L and SHR-H showed values of BP (147.9±8.1 and 139.3±10.6 mmHg) significantly lower than the SHR-C (211.6±11.9 mmHg, P<0.01 for both comparisons), while no differences were found between the former two groups. The SRM was intact in SHR-L and SHR-H, both groups showing, during the retention trial, a significantly higher percentage of entries in the novel arm in comparison with the other two arms (P<0.05 and P<0.01). These results were not due to effects of the drugs on locomotion or anxiety levels since neither of the groups showed behavioral differences in the EPM nor OF tests. It is concluded that the chronic treatment with Losartan or Hydralazine protects from the worsening of SRM in adult SHR. Key words SHR Losartan Hydralazine Memory