M. Sharma et Yk. Gupta, Effect of chronic treatment of melatonin on learning, memory and oxidativedeficiencies induced by intracerebroventricular streptozotocin in rats, PHARM BIO B, 70(2-3), 2001, pp. 325-331
Intracerebroventricular (ICV) streptozotocin (STZ) has been shown to cause
cognitive impairment, which is associated with free radical generation in t
he brain of rats. Melatonin is a potent free radical scavenger and antioxid
ant. In the present study, the effect of melatonin was investigated against
ICV STZ induced cognitive impairment and oxidative stress in rats. Adult m
ale Wistar rats were injected with ICV STZ (3 mg/kg) bilaterally. The rats
were treated with STZ twice, on days I and 3. The learning and memory behav
ior was assessed using passive avoidance paradigms, elevated plus maze and
the closed field activity while the parameters of oxidative stress assessed
were malondialdehyde (MDA) and glutathione. The rats were treated chronica
lly with melatonin for 21 days starting from day I of STZ injection. The le
arning and memory behavior was evaluated on days 17, 18 and 19 and the rats
were sacrificed on day 21 for estimation of MDA and glutathione. The rats
treated with melatonin showed significantly less cognitive impairment. Ther
e was also insignificant increase in brain MDA and decrease in glutathione
levels in melatonin-treated ICV STZ rats as compared to the vehicle-treated
ICV STZ animals. The study demonstrates the effectiveness of melatonin in
preventing the cognitive deficits as well as the oxidative stress caused by
ICV STZ in rats and suggests it's potential in age and age-related neurode
generative disorders where oxidative stress and cognitive impairment are in
volved. (C) 2001 Elsevier Science Inc. All rights reserved.