[Comparison of serum and erythrocyte superoxide dismutase in myocardial infarction and healthy people]

Despite of success in treatment of cardiovascular diseases by drugs and other methods, cardiovascular diseases and myocardial infarction are the most common causes of death in the developing countries. Many reports have been published about correlation between free radicals and increase of homocysteine with atherosclerosis pathogenesis. The aim of this research was to study the correlation between the heaelevation of homocysteine with changes of superoxide dismutase [GPx] activity after myocardial infarction. This research was a descriptive cross-sectional study that performed in 2006. In fasting condition, blood was taken from 48 patients and 48 normal healthy people under 76 years old. Serum homocysteine was determined by ELISA method, erythrocyte GPx [rGPx] activity assayed by Randox company kit and serum GPX [sGPx] activity assayed by Cayman chemical company kit. 36 men and 12 women were in the patien group, while the control group included 29 men and 19 women. The mean of homocysteine in patients were 30.3 +/- 5.3 micro mol/L and in controls were 11.1 +/- 3.1 micro mol/L, that it showed a significant difference between two groups [p<0.001]. The mean activity of sGPx in patients and controls were 2705 +/- 2078 U/g Hb and 2509 +/- 2450 U/g Hb, respectively. The mean activity of rGPx in patients and controls were 47.8 +/- 25.6 U/ml, 44.8 +/- 24.6 U/ml, respectively. In this study, an increase in homocysteine, sGPx and rGPx was observed in patients in compared with controls; however the increase of GPX was not significant. It seems that the elevation of GPX is due to cellular damages. This enzyme inhibits free radicals

[Verapamil enhances the impairing effects of stress on retrieval of long-term memory in rats]

This study investigated an interaction between acute restraint stress and verapamil, as a blocker of L-type voltage sensitive channels on retrieval of long-term memory. Young adult male rats were trained in one trial inhibitory avoidance task [1mA, 1.5s footshock]. On retention test given 48 hr after training, the latency to re-enter dark compartment and time spent in light chamber of the apparatus were recorded. Thirty min before retention test, the rats were exposed to a 10 min of restraint stress in a Plexiglass with or without prior treatment of verapamil [5, 10, 20 mg/kg]. The results showed verapamil pretreatment enhanced the impairing effect of stress on memory retrieval. The applied stress increased circulating corticosterone levels as assessed immediately after the retention test, indicating that stress-induced impairment of memory retrieval is mediated, in part, by increased plasma levels of glucocorticoids. Verapamil did not affect on this response. These findings indicate that acute restraint stress impair retrieval of long-term memory, and provide evidence for the existence of an interaction between stress and L-type voltage calcium channels on this process