Effect of violence films viewing on serum catecholamines and nitrites in male adolescents

This study is an attempt to determine the physiological effects of violence films viewing [VFV] in teenagers. For this purpose, 100 male teenagers volunteers [11-15 years] participated in this study. They were divided into 2 equal groups. The first group [Group I] was accustomed to VFV, while the second group [Group II] was not accustomed to VFV. Violence films [Natural Born Killer and Scream I "R-rated"] were viewed to participant volunteers for 3 hours. Blood samples were withdrawn before and after VFV [pre and post viewing samples]. Serum catecholamines [epinephrine [E], norepinephrine [N] and dopamine [D]] and nitrites [as an indicator of nitric oxide [NO]] were measured in pre-viewing and post viewing samples so that each participant acted as his own control. Results of the first group clearly revealed that serum catecholamines [E, N and D] levels were significantly increased. While nitrite levels were significantly decreased in post viewing samples compared to, pre- viewing samples. In the second group, serum E and nitrites were significantly increased, while serum N and D were significantly decreased in post viewing samples compared to pre-viewing samples. It is concluded that previous experience with VFV caused an aggressive stress response in group I; while lack of this past experience in group II was reflected as an attenuated stress response

Cardiovascular effects of violence films in male adolescents

In this study, the cardiovascular [CV] effects of violence film viewing [VFV] were studied. For this purpose, two groups of adolescent volunteers participated in this study. The first group [50 males aged 11-15 years] was violent film viewers, whereas the second group [50 males aged 11-15 years] was not accustomed to view violent film. Before included in the study, written consent and clinical examination were done. The CV parameters [blood pressures and ECG parameters] were recorded before and after VFV, so that each participant acted as his own control. These parameters were: Heart rate [HR], systolic and diastolic blood pressure [SBP and DBP], mean pressure [MP], pulse pressure [PP], the durations of P-R interval, QRS, Q-Tc, R-R interval, S-T segment and interval and the voltage of R and T waves. Statistical analysis of data showed that there were a significant increase in HR, SBP, DBP, PP and MP in group I after VFV compared to their control pre-viewing values. There were significant decrease in R wave and T wave voltage, the durations of P-R, QRS, Q-Tc, R-R and ST in group I after VFV compared to their control previewing values. In group II, there were significant decrease in HR. SBP, DBP, PP and MP after VFV compared with their previewing control values. While there were significant increase in R and T waves voltage, durations of P-R, QRS, Q-Tc [Q-T correct], R-R and ST after VFV compared with their control previewing values there. Previous experience with VFV resulted in sympathetic reactions whereas non accustomed to VFV showed parasympathetic reaction. This may be due to aggressive stress response associated with previous experience with VFV in group I while lack of this past experience could lead to less aggressive reactions in group II

Biochemical changes in brain catecholamines and serotonin during gastric ulcer induced by cold restraint stress in male albino rats

The present study was undertaken to investigate the chronological effect of cold restraint stress on the profile of biogenic amines [epinephrine, norepinephrine, dopamine and serotonin] in different areas of the brain, which are known to affect gastric function and are critically involved in the stress response [frontal cortex, hypothalamus and hippocampus]. Cold restraint stress was applied to pylorically ligated male albino rats in half hourly increasing duration [5-3 hr]. In the three selected brain areas, cold restraint stress produced a significant decrease in both norepinephrine and epinephrine concentrations and a significant increase in dopamine and serotonin levels. These changes in brain amines were significantly correlated with the increased duration of stress. The relevance of these findings was discussed

Role of glutathione status and nitric-oxide synthase activity in protection against ethanol-induced gastric mucosal injury in rats

The present study was devoted to investigate the effect of selenium chloride, N-ethyl maleimide [NEM] and N-nitro-L-arginine methylester [NAME] on ethanol-induced gastric lesions in rats. The ultimate aim was to explore further the possible role of endogenously formed glutathione and nitric oxide [NO] in the protection against ethanol-induced gastric mucosal injury in rats. All rats treated with 80 percent ethanol developed hemorrhagic ulceration. This was associated with a significant increase in lipid degradation products represented by increased levels of malondialdehyde; the degradation product of lipid peroxides, together with a significant decrease in gastric mucosal glutathione peroxidase [GSHPx] activity and mucosal glutathione [GSH]. Orally administered selenium chloride exerted significant protection against gastric mucosal injury induced by ethanol, possibly via increasing endogenous antioxidant reserve represented by increased GSHPx activity. This acts to scavenge oxygen free radicals produced during mucosal ischemia induced by ethanol with resultant decrease in rate of lipid peroxidation. Depletion of endogenous GSH by NEM had no potentially ulcerogenic effect in the control rats. However, when given before ethanol treatment, the ulcer index significantly increased. Lipid peroxides were not significantly affected in the control rats in spite of the significant depletion of GSH. However, when the mucosa was challenged during ethanol treatment in the presence of depleted GSH and decreased GSHPx activity, oxygen free radicals failed to be buffered and lipid peroxides increased more significantly. Blocking NO synthase activity by NAME during alcohol treatment exaggerated the mucosal lesions as revealed by a decrease of the preventive index. This supports the protective role of endogenous NO on the gastric mucosal injury induced by ethanol. The aggressive effect of NAME was accompanied with a significant decrease of GSHPx activity as well as of endogenous GSH. The lipid peroxides, however, were found to be reduced despite the decreased antioxidant activity. In conclusion, repletion of gastric GSHPx system by selenium chloride exerts cytoprotective effect while blockade of endogenous GSH via NEM or blockade of NO synthesis with NAME aggravated the alcohol-induced gastric lesions

Serum and gastric tissue changes in lithium calcium and zinc ions during stress and their correlation to the gastric stress ulcers in albino rats

48 adult male albino rats of an average weight of 150 to 200 g were used to study the effect of different stressors; restraint, water immersion and cold exposure on both serum and gastric tissue Ca2+, Li+ and Zn2+ levels and their correlation with the changes in composition of gastric juice and with the development of gastric stress ulcers. Zinc sulphate pretreatment was also studied to test for a possible protective effect. The gastric juice was collected after pyloric ligation and analyzed for the volume, total acidity and proteolytic activity. Both serum and gastric tissue Ca2+, Li+ and Zn2+ were measured and the gastric mucosal lesions were scored. The ulcer and preventive indices were then calculated. The results were compared with those of a control non stressed group. It was found that all forms of stress reduced significantly the rate of gastric secretion probably secondary to gastric mucosal ischaemia. Neither the serum nor the gastric tissue levels of the gastric stimulant Ca2+, or the gastric inhibitory Li+ and Zn2+ are significantly changed and hence their role in the secretory changes and stress ulcer development was not evident. However, increasing the serum and gastric tissue Zn2+ concentration following zinc sulphate pretreatment could inhibit gastric secretion and exert a protective effect against the different forms of stress ulcer

Effect of natural atrial natriuretic factor on suprarenal cortical function in albino rats

63 adult female Sprague-Dawly albino rats were used to study the effect of natural ANF [atrial extract] on suprarenal cortical functions. Forty rats were sacrificed and used for preparation of the natural atrial extract, while the rest were classified into three groups; group I [7 rats] received no treatment and served as control I, group II [8 rats] were intravenously injected by 0.5 ml of phosphate buffered saline /rat and served as control II, and group III [8 rats] were injected by 0.5 ml of atrial extract/ rat and served as ANF treated group. Blood samples were taken from the rats 20 minutes after injection and plasma Na [+] and K [+] were determined by flame photometry and plasma cortisol and aldosterone levels by radioimmunoassay technique. Histochemical study of suprarenal cortical cholesterol concentration was also done to assess steroidogenesis. It was found that atrial extract produced a significant decrease in plasma Na[+] with no change in K[+], a significant decrease in plasma aldosterone with no effect on plasma cortisol levels, and an increase in cholesterol concentration in zona glomerulosa but not in zona fasciculata of the suprarenal cortex. It was concluded that atrial extract block selectively the conversion of cholesterol to pregnenolone in the zona glomerulosa but not in the zona fasciculata, hence it inhibits the biosynthesis of aldosterone but not cortisol. This is probably an additional mechanism through which atrial extract may exert a natriuretic response