Stress response modulating effects of lactic acid in mice

Lactic acid is commonly found in sour milk and is often consumed with food, which plays a role in various biochemical processes and used for trauma, surgery, burn injury and as a neuroprotective. Present pilot study was designed to investigate its putative stress response modulating effects in male mice. A battery of behavioural test models viz. stress-induced hyperthermia, tail suspension test and pentobarbital-induced hypnosis was used to assess the adaptogenic activity of lactic acid. Doses of lactic acid (5, 25, 125 and 625 mg/kg) as solution (10 ml/kg) was prepared in distilled water and administered orally for 11 consecutive days. The body weight and body temperature were recorded daily as a measure of stress induced changes. Stress induced hyperthermia test was performed on 1st, 5th, 7th, and 10th day of the treatments. On 11th day, they were subjected to tail suspension test and on day 12th to pentobarbital induce hypnosis test. Stress-induced hyperthermia was reduced by lactic acid in dose dependent manner and also compensated the changed in body weight and basal rectal temperature due to daily handling and intermittent foot-shock stress. Test drug was also reduced the immobility period in tail suspension test and showed considerable effect on onset and duration of sleep in pentobarbital-induce hypnosis test when compared to control, the significant (p<0.05) activity of lactic acid was found at dose 25 mg/kg onwards. These observations indicate that lactic acid has potential for adaptogenic activity, suggesting its use against varied spectrums of psychopathologies associated with stress.