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Aim To determine whether AngⅡin para-ventricular nucleus (PVN)was involved in the chronic intermittent hypoxia (CIH ) induced-hypertension in rats.Methods Male Sprague-Dawley rats were ran-domly divided into Sham and CIH groups,the Sham rats were exposed to continuous normoxia,while the CIH rats were submitted to CIH (8 h per day for 15 days).The conscious noninvasive method with tail cuff was performed in rats to record the systolic blood pres-sure during establishing the model of CIH induced hy-pertension.Mean arterial pressure (MAP)and heart rate (HR)were recorded in vivo on a PowerLab data acquisition system after CIH.Rats were fixed on the stereotaxic instrument to conduct microinjection in the PVN.We used Western blot to measure Ang Ⅱ level and AngⅡtype 1 receptor (AT1 R)protein expression in PVN.Results The level of PVN Ang Ⅱin CIH rats was significantly higher than that in Sham rats,a-long with increased AT1 R protein expression.Microin-jection of Ang Ⅱ(0.03,0.3,3 nmol)in bilateral PVN dose-dependently increased MAP in both CIH and Sham rats,and this response was significantly augmen-ted in CIH rats.Losartan (50 nmol),AT1 R antago-nist,had no effect on MAP in Sham rats,but caused significant MAP decreases in CIH rats,and prevented Ang Ⅱ-induced increases in MAP in both CIH and Sham rats.Conclusion The results suggest that the increased AngⅡrelease and enhanced AT1 R activation in the PVN contribute to CIH induced-hypertension in rats.
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Objective To investigate the oxidative stress status and cardiac myocyte apoptosis in rats with propylthiouracil-induced hypothyroidism and to examine the effect of levothyroxine ( LT4 ),vitamin E ( VitE ),and both supplementation on this experimental model.Methods Male Sprague Dawley rats were divided into normal control group( NC),propylthiouracil group( PTU ),LT4 treatment group( PTU + LT4 ),VitE treatment group ( PTU +VitE),LT4 and VitE combination therapy group (PTU + LT4 + VitE).Serum T3,T4,TSH levels,serum and myocardial superoxide dismutase ( SOD ) activity and malondialdehyde ( MDA ) content were determined.Cardiac myocyte apoptotic index was made with TUNEL.Results ( 1 ) Compared with NC group,T3 and T4 levels were significantly lower and TSH level was significantly higher in PTU group and PTU+VitE groups( P＜0.05 ).Compared with PTU group,T3 and T4 levels were significantly higher and TSH level was significantly lower in PTU + LT4 group and PTU + LT4 + VitE group( P＜0.05 ).There were no statistical differences in T3,T4,and TSH levels between PTU group and PTU + VitE group( P＞0.05 ).( 2 ) Compared to NC group,serum and myocardial MDA levels in PTU group increased significantly( P＜0.05 ),serum SOD activity decreased significantly ( P＜0.05 ),while myocardial SOD activity showed no significant difference( P＞0.05 ).( 3 ) Compared with NC group,myocardial apoptosis index was significantly higher in PTU and PTU + VitE groups( P＜0.05 ).Compared with PTU group,myocardial apoptosis index was significantly lower in PTU + LT4 group and PTU + LT4 + VitE group( P＜0.05 ).Conclusion LT4,VitE,and their combined treatment of hypothyroidism in rats reduce the myocardial cells apoptosis,which may be related to the improvement of thyroid function and amelioration of oxidative stress.
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AIM To study the role of serot on in (5-HT) in ventrolateral preoptic nucleus(VLPO) on sleep and wakefulness cycl e of rat by microinjection of 5-hydroxytryptaphan (5-HTP , precursor of 5-HT ) , non-special 5-HT receptor antagonist methysergide (MS) and 5-HT retake i nhibitor fluoxetine. METHODS Stereotaxic, microinjection and po lysomnography (PSG) were used in the experiment. RESULTS There was no significant effect by microinjection of 5-HTP(0 5 ?g,0 1 ?l) into VLPO,but microinjection of 5-HTP(1 ?g,0 1 ?l)and fluoxetine lead wake i ncreased and sleep decreased; while microinjection of non-selective serotonin receptor antagonist MS lead to the opposited effect. The chang of sleep-wakefu lness cycle caused by 5-HTP or MS were significantly assiociated with time. CONCLUSION 5-HT involved in the regulation of sleep-wake cycle a nd promoted wake in the VLPO and its role of promotion may involve the gene exp ression of post-synaptic neurons.
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AIM To investigate the role of serotonergic projection from dorsal raphe nuclei (DRN) to basolateral amygadaloid (BLA) in the regulation of sleep and waking state. METHODS stereotaxic microinjection and polysomnography were employed. RESULTS Microinjection of L Glu into the DRN caused an enhancement of wake (W) and a decrease of slow wave sleep (SWS) and paradoxical sleep (PS). However, microinjection of L Glu into the DRN plus bilateral microinjection of methysergide (MS) into the BLA reversed the effects of L Glu. Microinjection of PCPA into the DRN caused an enhancement of SWS and a decrease of W. Microinjection of PCPA into the DRN plus bilateral microinjection of 5 HTP into the BLA reversed the effects of PCPA. CONCLUSION These results suggest that the role of the DRN in the regulation of sleep and waking state is partly mediated by serotonergic projection from the DRN to the BLA.