Memantine effects on liver and adrenal gland of rats exposed to cold stress

Male rats divided into 4 groups: 1)Control (CON); 2)Memantine (MEM); 3)Induced cold stress (IH) and; 4)Induced cold stress memantine (IHF). Memantine were administrated by gavage (20 mg/kg/day) during eight days. Cold stress were performed during 4 hours once at - 8°C. Lipid and glycogen depletion were presented as its intensity levels.Rats exposed to cold stress presented the highest glycogen (p < 0.001) and lipid depletion (p < 0.001) in liver and adrenal gland, respectively. We noted that memantine significantly reduced lipid depletion in adrenal gland and glycogen depletion in liver.Memantine prevented glycogen depletion in liver and lipid depletion in adrenal gland of rats under a cold stress condition.More than 60 years ago, Selye [1] recognized that the physiological system was activated by stress, and that protecting and restoring the body could also damage the system [2-5]. Induced cold state by low temperature exposure is considered as an important stressing physical agent [6]. Previous studies reported that acute exposure to cold stress besides impair heart tissue [7-9] cause lipid depletion in adrenal gland and glycogen depletion in liver [10], suggesting that the sympathetic activity and oxidative stress are the source of such fact.It is well established that glutamate excitotoxicity triggers neurodegeneration in acute brain injury conditions such as stroke, status epilepticus and head trauma. Drugs that block N-methyl-d-aspartate (NMDA) glutamate receptors are known to be neuroprotective in animal models for studying these acute brain injury conditions [11,12]. Memantine is a non-competitive antagonist at NMDA receptors and it is currently used to treat subjects with moderate to severe Alzheimer's disease to improve cognitive symptoms [13].Although it was indicated that glutamate receptors antagonists reduces oxidative stress mechanism in neurologic diseases [14], no study focused its effects on liver and adrenal gland in an acute cold stress situation