Reticuloendothelial function in acute noise stress.

Wistar strain albino rats of either sex were subjected to acute noise stress (3000 Hz at > 97 dB) for 30 minutes. Carbon clearance test was conducted in noise stressed animals immediately after the stress period. Significant (P < 0.001) increase of the clearance constant K was observed in stressed animals compared to the controls, indicating increased phagocytic activity of the reticuloendothelial system.

Effect of acute heat stress on certain immunological parameters in albino rats.

The effect of acute heat stress on certain immunological parameters were studied in male albino rats. The test rats were exposed to an ambient temperature of 40 degrees celsius for 30 minutes and sacrificed immediately. Total WBC count, Differential count, Phagocytic index, NBT reduction, organ weight body weight ratio of spleen, thymus, and popliteal lymph nodes, and soluble immune complex levels were measured in control group and the heat stressed animals. The heat stressed animals show decrease in total WBC count, and neutrophilia, eosinophilia, and lymphocytopenia. The phagocytic index showed a significant increase whereas the avidity index showed a decrease from the control value. NBT reduction was also significant. The soluble immune complex level was not altered. The heat stressed animals showed a decrease in the thymus and spleen weight/body weight ratio while the lymph node/body weight ratio showed an increase compared to the control animals.

Certain immunological parameters in subacute cold stress.

The effect of subacute cold swimming stress on the immune system of albino rats was investigated. Subacute cold stressed animals showed an increase in total WBC count, eosinophils and basophils. Phagocytic index and avidity index were also increased indicating hyperactive phagocytic process. On the other hand NBT reduction and soluble immune complex levels decreased significantly in stressed animals. There were no significant changes in the weight of the lymphoid organs.

Studies on monoamine levels in rat myocardium in different stresses.

Albino rats were exposed to isolation, haemorrhagic, and psychic stress. The myocardial norepinephrine (NE), epinephrine (E), dopamine (DA), 5-hydroxytryptamine (5HT) and 5-hydroxy indole acetic acid (5HIAA) were quantitatively estimated at varying periods of time. The results indicate that 5HT, E, and DA are the common denominators in various types of stress and show similar qualitative changes in all the stresses studied whereas norepinephrine shows both quantitative and qualitative differences in the various stresses studied indicating thereby a differential modulatory mechanisms operating for the release of noradrenaline.

Effect of flickering light stress on certain biochemical parameters in rats.

The acute effects of flickering light of 80 Lux intensity for thirty minutes duration, on plasma corticosterone, total serum cholesterol, serum triglycerides, serum glutamic pyruvic transaminase (SGPT) and serum glutamic oxaloacetic transaminase (SGOT) levels were studied in albino rats. Statistically significant increase was observed in the corticosterone, cholesterol, SGOT and SGPT, while a marked reduction was seen in the serum triglyceride level, indicating that the flickering light is a potent stressor to these animals causing alterations in the biochemical parameters studied.

Biochemical changes in acute noise stress in rats.

The effects of acute auditory stress on certain biochemical parameters like blood corticosterone, total cholesterol, triglyceride, Serum glutamic pyruvic transaminase (SGPT) and Serum glutamic oxaloacetic transaminase (SGOT) were studied in albino rats. A significant increase was observed in the blood level of corticosterone, total cholesterol, SGOT and SGPT while a marked reduction was noticed in the Sr. triglyceride level. These data indicate that noise could be a potent stressor and cause disturbances in the biochemical parameters of the body. It is presumed that most of the effects are indirect, being manifested through the activation of autonomic nervous system which liberates catecholamines and hypothalamo pituitary adrenal axis responsible for the liberation of corticosteroids.

Influence of isolation stress on monoamine levels in discrete regions of the rat brain correlated with behaviour.

Various forms of stressful stimuli have been shown to affect brain catecholamine (CA) and indoleamine (IA) levels, although the literature contains some conflicting views. Changes in monoamine levels were also found to accompany the behavioural changes in animals. In the present study an attempt was made to correlate the behavioural changes with the monoamine level in discrete regions of rat brain after different periods of isolation stress. The results clearly indicate that not only the central norepinephrine and dopamine neurons involved in the expression of aggressive behaviour after isolation stress but also the serotoninergic neurons might take part.