Modulation of serum cortisol by substance P in albino rats: evidence of a direct effect on adrenal gland.

Effect of prolonged administration of substance P on the plasma cortisol level in the albino rats has been investigated. An inhibitory impact on intact individuals and a stimulatory effect in pharmacologically annulled rats has been observed. It is concluded that in normal conditions substance P presumably acts as a preventive agent for any excess secretion of cortisol while during stress or disturbed HPA or RAS conditions, it stimulates the secretion of cortisol. An intraglandular modulatory role of substance P has been suggested.

Lidando com o estresse: o cotidiano do enfermeiro ao assistir uma criança com câncer em uma unidade intensiva pediátrica

O presente trabalho sob a forma de anteprojeto, abordando a temática do estresse, tem por objetivos: identificar e analisar o estresse físico, psicológico e emocional provocado pelo impacto do cenário oncológico nos enfermeiros intensivistas pediátricos, para que possam ser elaboradas estratégias que venham a minimizar os efeitos dos fatores estressores nos referidos profissionais. Para tanto, utilizaremos os referenciais teóricos sobre estresse, as condições de trabalho e estresse, a patologia câncer e seu impacto e o cuidar da criança com câncer. Utilizaremos, quanto aos fins, a metodologia descritiva com abordagem quantitativa. Os sujeitos da pesquisa serão os enfermeiros atuantes no Centro de Terapia Intensiva (CTI) pediátrico do Hospital do Câncer I (HCI) - Instituto Nacional de Câncer (INCA), que irão responder a dois questionários, que abordarão dados de caracterização pessoal e as características evidenciáveis do estresse. A realização desta pesquisa tem o intuito de contribuir para uma melhoria na qualidade de vida e trabalho desses enfermeiros, e, conseqüentemente, melhoria na qualidade da assistência prestada.

Chronic mild stress decreases survival, but not proliferation, of new-born cells in adult rat hippocampus

New-born cells continue to proliferate and survive to become mature granule cells in adult rat hippocampus. Although this process, known as neurogenesis, is inhibited by acute stress, it is not clear whether chronic stress affects neurogenesis. To determine whether chronic mild stress (CMS) influences neurogenesis in the adult rat hippocampus, male Sprague-Dawley rats were exposed to CMS and administered bromodeoxyuridine (BrdU) before or after CMS to observe the survival/differentiation or proliferation of new-born cells, respectively. In addition, we measured brain-derived neurotrophic factor (BDNF) mRNA in the granule cell layer (GCL) of the hippocampus, because BDNF is known to play an important role in the survival of new-born cells. CMS significantly decreased the survival of newborn cells in the GCL, but did not influence the proliferation or differentiation of new-born cells. CMS did not affect the proliferation and survival of new-born cells in the hilus. In addition, CMS did not change BDNF mRNA levels in the GCL. These results demonstrate that CMS reduces the survival of new-born cells but not of their proliferation, suggesting that repeated mild stress could influence a part of neurogenesis, but not the whole part of neurogenesis. These results raise the possibility that the survival of new-born cells may be suppressed in the presence of normal BDNF mRNA levels in GCL.

Stress induced neuron degeneration and protective effects of Semecarpus anacardium Linn. and Withania somnifera Dunn. in hippocampus of albino rats: an ultrastructural study.

Effects of herbal formulations were studied on hippocampal neuron cell bodies. Study was carried out in adult Swiss albino rats. Experimental rats (E) were divided into three groups. Group E1 rats were given immobilization stress for 14 hr/day for 30 days. Rats in E2 and E3 group were given daily single dose (40 mg/kg/body wt.) of alcoholic extract of S. anacardium and W. somnifera. After 1 hr giving the plant extract, the rats were subjected to stress. Treatment continued for 14 hr for 30 days. Control rats were kept in complete nonstress condition. Ultrastructural characteristics of neuron cell bodies in hippocampal sublayer (CA1-CA4 and Dg) was studied in rats of E1, E2 and E3 groups and compared with control. Results of the present study demonstrated, that both CA2 and Dg, 85% of neuron cell bodies exhibited degenerating characteristics, (which includes karyorrhexis, membrane blebbing, chromatin condensation, chromatin fragmentation and intracellular spacing). Interestingly, after the treatment with S. ancardium cells demonstrating degenerating characteristics was significantly reduced (80%) as compared to treatment with W. somnifera. Study suggests that probably both the herbal drugs have cytoprotective properties.

Influence of different types of stress on selected cardiovascular parameters in rats.

Wistar strain male albino rats were exposed to different types of stressors like isolation, immobilization, overcrowding and forced swimming, for a duration of one day, 7 days, 15 days and 30 days and the effect on heart weight, adrenal weight, heart rate, P-R interval and serum transaminase levels were studied. There was a significant increase in the heart weight and adrenal weight in most of the stress subgroups. Tachycardia was seen in all the types of stress upto 7 days, except in the case of overcrowding stress. Serum transaminase level increased significantly in all the types of stress. Among the different types of stress, immobilization and forced swimming had greater effect on the heart weight and heart rate. Increase in the heart rate and heart weight was observed only in the initial period of exposure to a stressor and when the animals were exposed to a prolonged stressor like 15 days and 30 days, there was no further increase in the heart weight and heart rate which may be due to the adaptation of the animal to a chronic stressor.

Effects of heat-stress in rats, III. On pregnant rats, maternal organs and foetal tissues.

Exposure of intact and ovariectomized rats to high ambient temperature (34.4 degrees C, 60-65% relative humidity) resulted in reduction of their body weight, increased water consumption. The feed consumed which was lowered by 25% initially, did not alter later. Intact rats were also subjected to a still higher ambient temperature of 36.6 degrees C and 70 to 75% RH and the effects were observed. When compared with 'controls' no significant changes in the weights of ovaries or pituitary gland were seen due to heat stress in intact rats. But, the latter weighed heavier in ovariectomized rats. Adrenal glands were found enlarged and weighed more both in intact and ovariectomized rats. The average foetal weight due to high ambient temperature in intact rats was lower, but in ovariectomized rats it weighed more. Similarly, the average weight of the placenta was lower in intact rats but higher in ovariectomized rats due to thermal stress.