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@#Objective To investigate whether cold or heat stress affected signal transduction of p38 mitogen-activated protein kinase (MAPK) in the spinal cords and ganglia.Methods The rat models of acute cold and heat stresses were established, and the immunohistochemistry and Western blotting analysis were used.Results The phospho-p38 (p-p38) immuno-positive cells were observed in the Rexed Ⅱ layer of normal thoracic spinal cord, with low cell density and brown nucleus staining, and without staining in Rexed Ⅲ～Ⅹ layers. In the spinal ganglia, the p-p38 immunoreaction was mainly located in the nuclei of a few small-sized neurons. Acute heat stress (10 min & 20 min) reduced the number of positive cells in Rexed Ⅱ layer, with body-temperature (38℃) stress (20 min) having no effect. No immunostaining was changed in the spinal ganglia. Acute cold stress (10 min & 20 min) slightly reduced the positive cells in the Rexed Ⅱ layer, with unchanged immunostaining in spinal ganglia. Western immunoblot analysis showed that activation level of p-p38 was differently downregulated by heat and cold stresses compared to the normal groups and body temperature (38℃)-bathed groups.Conclusion Constitutive activation of p38 can be observed in the normal spinal cord and ganglia; heat stress and cold stress significantly and gentlely inhibite the phosphorylation level of p38, respectively.
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@#Objective To investigate the effects of estrogen on brain derived neurotrophic factor (BDNF) and neuropeptide Y (NPY) levels in cerebellar cortex of ovariectomized rats. Methods 24 female Wistar rats were randomly divided into three groups: intact (INT) group, ovariectomized (OVX) group, and OVX+estrogen 0.5 mg/kg every day group (E group). Radioimmunoassay (RIA) was used to measure the estrogen content in plasma, and the levels of BDNF and NPY were measured with Immunohistochemistry. Results Compared with the INT group, the plasma estrogen level significantly reduced in OVX group (P<0.001). However, the plasma estrogen level was higher in the E group than that in the OVX group (P<0.001). The BDNF and NPY presented in the Purkinje cell layer,and BDNF also distributed in the molecular layer and granular layer. Compared with that in the INT group, BDNF and NPY positive cells markedly decreased in OVX group, with slight cytosol staining in the cerebellar cortex (P<0.001). The BDNF and NPY positive neurons increased in E group compared with that in the OVX group (P<0.001). Conclusion Estrogen can increase the BDNF and NPY levels in cerebellar cortex of female rats, which may protect the structure and function of cerebellar neurons.
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@#Estrogen is an important active endogenous substance which is needed by female to sustain normal psychological and physiological function.Studies have demonstrated that estrogen has an extensive effect on the central nervous system.This review explained the relation between estrogen and learning on a few aspects such as neurobiochemistry,neurophysiology,neuroanatomy,signal transduction and so on.
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Objective To investigate the effects of estrogen on extracellular signal-regulated kinase-1/2(ERK1/2) phosphorylation levels in hippocampal CA4 region of ovariectomized rats. Methods Experimental female Wistar rats were randomly divided into three groups: intact (INT) group, ovariectomized (OVX) group, and OVX+estrogen (1 mg/kg, weekly) group. Radioimmunoassay (RIA) was used to measure the estrogen content in plasma, and the levels of ERK1/2 phosphorylation were measured with immunohistochemistry. Results Compared with the control animals, the plasma estrogen level was significantly lower in OVX group (P＜0.001). However, the plasma estrogen level was higher in the OVX+estrogen group than that of the OVX group (P＜0.001). Immunohistochemical staining showed that the phospho-ERK1/2 (p-ERK1/2) substances were present in the nucleus and cytosol of neurons. Compared with the control group, immunostaining positive cells markedly decreased in OVX group, with light nucleus and cytosol staining in the hippocampal CA4 region (P＜0.001). The phospho-ERK1/2 positive neurons increased more obviously in OVX+estrogen group than in the OVX group (P＜0.001). Conclusion Estrogen can increase ERK1/2 phosphorylation levels in hippocampi of aging female rats, which suggests that the ERK signal transduction pathway may be regulated by estrogen during the process of aging.
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@#Objective To determine the regulation of electroacupuncture(EA)at Zusanli acupoint for the expression of estrogen receptors mRNA in the brain of ovariectomized rats.MethodsFemale Wistar rats were randomly divided into 3 groups:intact group(INT),ovariectomized group(OVX),and ovariectomy and acupuncture group(OVX+EA).Radioimmunoassay(RIA)was used to measure the estradiol(E2)and testosterone(T)levels in plasma.The mRNA levels of estrogen receptor(ER)α and ERβ in the brain of rats were measured with RT-PCR.ResultsThe levels of endogenous estrogen increased significantly in OVX+EA rats compared with OVX rats(P<0.01),while the plasma T levels were lower in the OVX+EA group than those of the OVX group(P<0.01).Eelectroacupuncture can up-regulate ERα expression in the brain of ovariectomized rats(P<0.01).However,it was shown to have a down-regulatory effect on the levels of ERβ expression(P<0.01).ConclusionThere is an intimate relationship between the expressions of estrogen receptors mRNA and the endogenous hormone levels,such as E2 and T.Electroacupuncture can regulate the expression of estrogen receptors mRNA in the brain and the E2 and T levels in plasma of ovariectomized rats,which might,at least in part,explain the mechanisms of acupuncture adjusting the neuroendocrine system.
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Objective To study the protection effect of acupuncture at acupoint ST 36 in rat with cold-restrainted stress-induced ulcer,and to observe the expression of NOS in hypothalamus and adrenal. Methods Ulcer Index in rats was used to study the protection effect of acupuncture, and and RT-PCR was employed to study the expression of NOS in hypothalamus and adrenal. Images were analyzed with semi-quantitative method. Results The ulcer Index was significantly decreased in rats with stress-induced ulcer by acupuncture as indicated by a comparison with those without acupuncture. The expression of NOS1 in hypothalamus was increased by acupuncture protect stress-induced ulcer. The increased expression of NOS2 was involved in stress-induced ulcer, and acupuncture decreased its expression. The expression of NOS3 in hypothalamus had the similar reaction to NOS2, but the decreased effect of acupuncture was limited. The expression of NOS1 and NOS3 in adrenal were increased by cold stress, only the expression of NOS1 could be repressed with acupuncture. There was no NOS2 expression in adrenal in stress-induced ulcer rats. Conclusion The protection effect in stress-induced ulcer exerted by acupuncture at acupoint ST 36 were mediated by increase of the physiological expression of NOS1 in hypothalamus as well as decrease of the expression of NOS2,NOS3 in hypothalamus and repress of the expression of NOS1 in adsenal.