Memantine Prevents Cardiomyocytes Nuclear Size Reduction in the Left Ventricle of Rats Exposed to Cold Stress

OBJECTIVES Memantine is an N-methyl-d-aspartate (NMDA) glutamate receptor antagonist used to treat Alzheimer's disease. Previous studies have suggested that receptor blockers act as neuroprotective agents; however, no study has specifically investigated the impact that these drugs have on the heart. We sought to evaluate the effects of memantine on nuclear size reduction in cardiac cells exposed to cold stress. METHOD We used male EPM-Wistar rats (n=40) divided into 4 groups: 1) Matched control (CON); 2) Memantine-treated rats (MEM); 3) Rats undergoing induced hypothermia (IH) and 4) Rats undergoing induced hypothermia that were also treated with memantine (IHM). Animals in the MEM and IHM groups were treated by oral gavage administration of 20 mg/kg/day memantine over an eight-day period. Animals in the IH and IHM groups were submitted to 4 hours of hypothermia in a controlled environment with a temperature of -8 degrees C on the last day of the study. RESULTS The MEM group had the largest cardiomyocyte nuclear size (151 +/- 3.5 microm(3) vs. CON: 142 +/- 2.3 microm(3); p<0.05), while the IH group had the smallest mean value of nuclear size. The nuclear size of the IHM group was preserved (125 +/- 2.9 microm(3)) compared to the IH group (108 +/- 1.7 microm(3); p<0.05). CONCLUSION Memantine prevented the nuclear size reduction of cardiomyocytes in rats exposed to cold stress.