神经节苷脂钠对缺血性脑卒中小鼠空间学习记忆能力的影响

摘要 目的：探讨神经节苷脂钠对缺血性脑卒中小鼠空间学习记忆能力的影响。方法：缺血性脑卒中小鼠模型(n=42)随机分为三组-模型组、氟西汀组与神经节苷脂钠组,每组14只小鼠。氟西汀组、神经节苷脂钠组、对照组分别给予10 mg/kg氟西汀与10 mg/kg神经节苷脂钠、等剂量生理盐水腹腔注射,1次/d,持续28 d。结果：氟西汀组、神经节苷脂钠组给药第7 d、14 d、28 d的逃避潜伏期、改良神经损伤严重程度评分(Modified neurological severity score,mNSS)低于模型组(P<0.05),穿越平台次数高于模型组(P<0.05),神经节苷脂钠组与氟西汀组对比差异有统计学意义(P<0.05)。氟西汀组、神经节苷脂钠组给药第28 d的海马组织B淋巴细胞瘤-2基因(B-cell lymphoma-2,Bcl-2)蛋白相对表达水平高于模型组(P<0.05),BCL2-Associated X(Bax)蛋白相对表达水平、脑卒中相对面积低于模型组(P<0.05),神经节苷脂钠组与氟西汀组对比差异有统计学意义(P<0.05)。结论：神经节苷脂钠在缺血性脑卒中小鼠的应用能促进恢复空间学习记忆能力,缓解神经损伤,抑制海马组织神经元细胞的凋亡,降低脑卒中面积。     

BNP/NPR-A/BKCa信号通路在大鼠神经痛形成中的作用及机制研究

摘要 目的：探讨BNP/NPR-A/BKCa信号通路在大鼠神经痛形成中的作用及机制研究。方法：选取SPF级大鼠作为研究对象,并构建神经痛病理性疼痛大鼠模型。并分为空白对照组、假手术组、A组（20 ng/mL BNP梢内注射）、B组（50 ng/mL BNP梢内注射）和C组（100 ng/mL BNP梢内注射）。采用qRT-PCR和Western blot检测NPR-A和BKCa的mRNA和蛋白表达水平。采用ELISA法检查炎症因子。全细胞膜片钳技术检测痛觉神经元BKCa通道电流;对大鼠进行机械性痛觉过敏测试和温度性痛觉敏感测试。结果：与空白组相比,模型组、A、B和C组PWT和PWL明显更低（P＜0.05）;与模型组相比,A、B和C组PWT和PWL明显更高,且C组大于B和A组,B组大于A组（P＜0.05）。与空白组相比,模型组NPR-A的蛋白和mRAN水平明显更高,而BKCa-α明显更低（P＜0.05）;与模型组相比,A、B和C组NPR-A和BKCa-α的蛋白和mRNA明显更高,且C组大于B和A组,B组大于A组（P＜0.05）。各电压水平,与空白组相比,模型组、A、B和C组BKCa-α电流水平明显更低（P＜0.05）;与模型组相比,A、B和C组BKCa-α电流水平明显更高,且C组大于B和A组,B组大于A组（P＜0.05）。与空白组相比,模型组、A、B和C组TNF-α、IL-6和IL-18水平明显更高（P＜0.05）;与模型组相比,A、B和C组TNF-α、IL-6和IL-18水平明显更低,且C组小于B和A组,B组小于A组（P＜0.05）。结论：靶向上调BNP的表达水平可增加BKCa的表达及BKCa电流,同时BNP的表达上调还有助于抑制炎症因子水平,从而达到多途径缓解疼痛的目的。     

七氟醚对脑缺血再灌注损伤大鼠认知功能及海马S100β及PGRN表达的影响

摘要 目的：探索用七氟醚预处理后脑缺血再灌注损伤大鼠的认知功能变化情况以及海马细胞内钙结合蛋白（S100β）及颗粒蛋白前体（Progranulin,,PGRN）的表达水平。方法：选取SPF级雄性大鼠36只,按照随机数字表法分为假手术组（A组）、脑缺血再灌注损伤组（B组）、七氟醚预处理组（C组）,每组12只。B组和C组大鼠采用线栓法建立脑缺血再灌注损伤模型,缺血2 h,再灌注24 h,假手术组仅切开不插入线栓。术前七氟醚预处理组大鼠吸入体积分数3 %七氟醚和氧流量为2 L/min的混合气体,持续1 h,假手术组和脑缺血再灌注损伤组单纯吸入2 L /min的氧气。建模完成后采用大鼠神经功能缺损评分（modified neurological severity score,mNSS）评估大鼠的神经功能状况;Morris水迷宫实验检测各组大鼠学习认知功能;Western Blot检测各组大鼠S100β和PGRN的表达情况。结果：（1）B、C组大鼠mNSS评分显著高于A组,C组评分较B组有明显降低（P＜0.05）;（2）与A组相比B、C两组逃逸潜伏期明显延长,C组与B组相比逃逸潜伏期显著缩短（P＜0.05）;（3）B、C组大鼠海马S100β和PGRN的表达较A组有显著上调,其中C组S100β表达较B组显著降低,PGRN表达显著升高（P＜0.05）。结论：本文通过观察七氟醚预处理对CIRI大鼠认知功能及海马S100β和PGRN蛋白表达水平的影响,发现七氟醚预处理对CIRI大鼠认知功能有显著提高,其作用机制与海马S100β和PGRN的表达密切相关,为进一步探索其作用机制提供参考证据。     

镁离子对谷氨酸诱发的海马神经元损伤的保护作用

目的 :探讨镁离子 (Mg2 )在 0 .1mmol/L谷氨酸诱发的海马神经元损伤中的作用。方法 :将神经元从新生SD大鼠海马中分离后培养 6～ 9d ,即随机分成三组 :A .单纯培养基 ;B .培养基 谷氨酸 ;C .培养基 Mg2 ,30min后再加入谷氨酸。结果 :①B组海马神经元存活率与A组相比显著地呈剂量依赖性降低。②与B组对照 ,C组加用低浓度的Mg2 可提高海马神经元的存活率。结论 :低浓度的Mg2 能保护谷氨酸诱发损伤的海马神经元     

丹参多酚酸盐通过SIRT3/β-catenin-PPARγ信号通路对心肌梗死大鼠的作用及机制研究

摘要 目的：通过制备心肌梗死大鼠模型，基于SIRT3/β-catenin-PPARγ信号通路探讨丹参多酚酸盐对心肌梗死大鼠的作用及相关机制，为将丹参多酚酸盐应用于心肌梗死治疗积累理论基础。方法：选取SPF级健康SD大鼠60只，随机分为假手术组（A组）、模型组（B组）、丹参多酚酸注射低剂量组（C组）丹参多酚酸注射高剂量组（D组）。B、C、D组大鼠制备为心肌梗死模型，A组大鼠仅进行假手术操作。B、C、D三组大鼠均接受丹参多酚酸盐注射治疗，A组大鼠注射等量生理盐水。比较各组大鼠心动图指标、血流动力学参数、心肌损伤相关指标、SIRT3/β-catenin-PPARγ信号通路相关蛋白及mRNA相对表达量。结果：干预后，B、C、D组大鼠的LVEF、LVFS和dP/dt max、dP/dt min均下降，且C、D组高于B组，D组高于C组；同时B、C、D组大鼠LVEDD高于A组，C、D组低于B组且D组低于C组。B、C、D组大鼠CK、CK-MB、LDH水平均高于A组，同时C、D组均低于B组，且D组低于C组；干预后，B、C、D组大鼠IL-1β、IL-6、TNF-α水平均高于A组，同时C、D组均低于B组，且D组低于C组；干预后，B、C、D组大鼠SIRT3、β-catenin蛋白表达量及mRNA表达量均高于A组，同时C、D组大鼠高于B组且D组高于C组；同时B、C、D组PPARγ蛋白表达量及mRNA表达量均高于A组，且C、D组低于B组，D组低于C组（P＜0.05）。结论：丹参多酚酸盐能够有效改善心肌梗死大鼠的心功能，缓解心肌损伤，其机制可能与调控SIRT3/β-catenin-PPARγ信号通路、下调炎性因子水平相关，且高剂量丹参多酚酸盐的治疗效果更优。     

香草醛对新生大鼠缺氧缺血性脑损伤的神经保护作用研究

摘要 目的：探讨香草醛对新生大鼠缺氧缺血性脑损伤(HIBI)的神经保护作用及机制。方法：参考Rice-Vannucci方法建立HIBI大鼠模型。HIBI大鼠建模后立即腹腔注射20 mg/kg（HIBI+20Van组）或40 mg/kg（HIBI+40Van组）的香草醛,每隔12 h给药,连续7 d。然后评估大鼠的神经行为及脑组织中IL-1β、IL-6和TNF-α的水平。对BV2小胶质细胞进行氧糖剥夺/复氧(OGD/R)处理,并用20 μM香草醛培养。通过Western blot及免疫荧光检测HMGB1、NF-κB p65、SIRT1、MyD88和TLR4的表达水平。通过乳酸脱氢酶（LDH）释放测定试剂盒测定用不同BV2细胞培养基处理的原代神经元的LDH释放。结果：与HIBI组比较,HIBI+20Van组和HIBI+50Van组新生大鼠的前肢悬吊时间和旷场得分均升高,脑组织中的IL-1β、IL-6和TNF-α的水平均降低。香草醛均升高了HIBI大鼠和OGD/R处理的BV2细胞质中的SIRT1的表达水平,降低了TLR4、MyD88和HMGB1的表达水平及细胞核中NF-κB p65的表达水平（P<0.05）。香草醛降低了原代神经元的LDH释放量（P<0.05）。结论：香草醛通过调节SIRT1/HMGB1/TLR4/MyD88/NF-κB信号通路抑制HIBI引起的神经炎症,从而提高HIBI大鼠的神经功能。     

七氟醚通过影响外周血miR-340水平逆转脓毒症大鼠巨噬细胞吞噬功能抑制状态的机制

摘要 目的：探究七氟醚通过影响外周血miR-340水平逆转脓毒症大鼠巨噬细胞吞噬功能抑制状态的机制。方法：60只雄性Sprague-Dawley大鼠根据研究目的将大鼠分为对照组、脓毒症组和七氟醚组。通过RT-PCR分析各组大鼠外周血miR-340以及促炎因子IL-1β、IL-6和TNF-α的mRNA表达水平。统计各实验组大鼠的存活率。通过血琼脂平板对各组大鼠腹腔液和血液中的细菌进行计数。通过使用荧光显微镜测量吞噬率和吞噬指数。通过蛋白印迹分析p65和NF-κB的蛋白表达。结果：脓毒症组miR-340水平较对照组升高（P<0.05）,七氟醚组miR-340水平较脓毒症组降低（P<0.05）。三组不同时间点存活率相比差异无统计学意义（P＞0.05）;第4 d、8 d脓毒症组大鼠存活率较对照组大鼠降低（P<0.05）,七氟醚组大鼠存活率较脓毒症组升高（P<0.05）。脓毒症组IL-1β、IL-6和TNF-α的mRNA表达较对照组升高（P<0.05）,七氟醚组IL-1β、IL-6和TNF-α的mRNA表达较脓毒症组降低（P<0.05）。脓毒症组腹腔液和血液中的细菌数量较对照组升高（P<0.05）,七氟醚组腹腔液和血液中的细菌数量较脓毒症组减少（P<0.05）。血琼脂平板对各组大鼠腹腔液和血液中的细菌进行计数,脓毒症组腹腔液和血液中的细菌数量较对照组升高（P<0.05）,七氟醚组腹腔液和血液中的细菌数量较脓毒症组减少（P<0.05）。脓毒症组p65和NF-κB的蛋白表达较对照组升高（P<0.05）,七氟醚组p65和NF-κB的蛋白表达较脓毒症组降低（P<0.05）。结论：miR-340参与了脓毒症大鼠巨噬细胞吞噬功能调节,七氟醚通过降低外周血miR-340水平减少内毒素诱导的大鼠促炎细胞因子的释放,并恢复巨噬细胞吞噬功能。     

柚皮苷和木犀草素联合应用对大鼠BMSCs诱导成骨过程中Wnt/β-cantein通路相关基因表达的影响

摘要 目的：探讨柚皮苷和木犀草素联合应用对大鼠骨髓间充质干细胞（BMSCs）诱导成骨过程中Wnt/β-cantein通路相关基因表达的影响。方法：取大鼠股骨中提取的BMSCs,分别建立A组（空白组）、B组给予柚皮苷溶液10 μmol/L,C组给予木犀草素溶液5 μmol/L;D组给予骨碎补总黄酮溶液10 mg/mL;E组给予柚皮苷-木犀草素混合溶液配伍比为10 μmol/L：5 μmol/L,并诱导其向成骨细胞分化。应用碱性磷酸酶（ALP）染色及分光光度法检测第7 d各组细胞ALP活性。应用实时荧光定量聚合酶链反应（qRT-PCR）检测第7 d各组细胞Wnt/β-cantein通路相关基因及成骨基因的表达。结果：B组、C组、D组、E组细胞562 nm波长下光密度（OD）值显著高于A组,E组细胞562 nm波长下OD值最高,显著高于B组、C组、D组（P＜0.05）。B组、C组、D组、E组细胞ALP、骨钙素（OCN）、Runt相关转录因子2（RUNX2）基因表达水平显著高于A组,E组ALP、OCN、RUNX2基因表达水平最高,显著高于B组、C组、D组（P＜0.05）。B组、C组、D组、E组细胞β-catenin、Cyclin D1基因表达水平显著高于A组;B组、E组LEF-1基因表达水平显著高于A组;E组β-catenin、LEF-1、Cyclin D1基因表达水平最高,显著高于B组、C组、D组（P＜0.05）。结论：柚皮苷和木犀草素均具有促进大鼠BMSCs增殖和诱导其成骨向分化的作用,柚皮苷和木犀草素联合应用诱导大鼠BMSCs增成骨作用最强,其主要机制与Wnt/β-cantein通路激活有关。     

淫羊藿苷缓解腹部皮瓣缺血再灌注损伤模型大鼠的作用及机制研究

摘要 目的：研究淫羊藿苷缓解腹部皮瓣缺血再灌注损伤（IRI）模型大鼠的作用及机制。方法：取30只SD级大鼠作为研究对象,将其按照随机数字表法分作假手术组、模型组以及淫羊藿苷组,每组各10只。其中模型组和淫羊藿苷组大鼠均制作大鼠腹部皮瓣IRI模型,假手术组以及模型组大鼠予以生理盐水腹腔注射,淫羊藿苷组大鼠则予以淫羊藿苷腹腔注射。对比各组大鼠皮瓣存活面积及存活率、血清炎症因子以及氧化应激指标水平、皮瓣组织中p38丝裂原活化蛋白激酶（p38 MAPK）信号通路相关蛋白表达情况。结果：模型组、淫羊藿苷组大鼠的皮瓣存活面积及存活率均低于假手术组,但淫羊藿苷组大鼠的皮瓣存活面积及存活率均高于模型组（P＜0.05）。模型组、淫羊藿苷组大鼠血清白细胞介素-10（IL-10）均低于假手术组,但淫羊藿苷组高于模型组;模型组、淫羊藿苷组大鼠血清肿瘤坏死因子-?琢（TNF-?琢）均高于假手术组,但淫羊藿苷组低于模型组（P＜0.05）。模型组、淫羊藿苷组大鼠血清超氧化物歧化酶（SOD）、谷胱甘肽（GSH）水平均低于假手术组,但淫羊藿苷组大鼠血清SOD、GSH水平均高于模型组;模型组、淫羊藿苷组大鼠血清丙二醛（MDA）水平均高于假手术组,但淫羊藿苷组大鼠血清MDA水平低于模型组（P＜0.05）。模型组、淫羊藿苷组大鼠皮瓣组织p38 MAPK、丝裂原活化蛋白激酶磷酸酶-2（MKP-2）相对表达量均高于假手术组,但淫羊藿苷组皮瓣组织p38 MAPK相对表达量低于模型组,而MKP-2相对表达量高于模型组（P＜0.05）。结论：淫羊藿苷可通过调控p38 MAPK信号通路缓解炎症反应及氧化应激,发挥减轻腹部皮瓣IRI的作用。     

绒毛膜促性腺激素对复发性流产大鼠子宫内膜厚度、雌激素受体表达及免疫因子表达的影响

摘要 目的：探讨绒毛膜促性腺激素对复发性流产大鼠的治疗效果,为临床中优化复发性流产的治疗方案提供理论基础。方法：选取未交配生育的SPF级雌性大鼠共40只,随机分为对照组（A组）、模型组（B组）、常规治疗组（C组）、绒毛膜促性腺激素治疗组（D组）,每组各10只。雌鼠妊娠后开始干预。A组大鼠全天仅灌服生理盐水。B组大鼠上午灌服生理盐水,C组大鼠上午灌服地屈孕酮水溶液,D组大鼠上午注射绒毛膜促性腺激素注射液,下午B、C、D组大鼠灌服羟基脲溶液。妊娠第十天给予各组大鼠灌服米非司酮。比较各组大鼠胚胎吸收率、炎性因子水平、免疫因子水平、雌激素受体表达水平及子宫内膜损伤程度。结果：干预后,与A组相比,各组大鼠胚胎吸收率增高,与B组大鼠相比,C组、D组大鼠的胚胎吸收率降低,且D组大鼠低于C组;与A组相比,各组大鼠IL-17水平、IL-17/ TGF-β、Th17细胞比例、Th17/Treg升高,且TGF-β水平、Treg细胞比例下降,同时C组、D组大鼠的IL-17水平、IL-17/TGF-β、Th17细胞比例、Th17/Treg均低于B组,且D组低于C组,同时TGF-β水平、Treg细胞比例高于B组,且D组高于C组;干预后,与A组相比,各组大鼠子宫内膜厚度下降,纤维化面积比例增加,与B组相比,C组、D组大鼠的子宫内膜厚度增加且D组高于C组,同时子宫内膜纤维化比例低于B组,且D组低于C组;与A组相比,各组大鼠ER、PR、PRLR mRNA表达水平明显降低,与B组相比,C组、D组大鼠的ER、PR、PRLR mRNA表达水平有所增加,且D组高于C组,差异均具有统计学意义（P＜0.05）。结论：绒毛膜促性腺激素可能通过调节炎性因子水平和免疫微环境,提高性激素、受体表达,进而修复子宫内膜损伤,降低胚胎吸收率,促进复发性流产的恢复。     

Distribution of the vasoconstrictor and vasorelaxant effects of norbormide along the vascular tree of the rat

Norbormide is a vasoconstrictor of rat peripheral arteries and a relaxant in rat aorta. To characterise norbormide actions within the rat vascular tree we have investigated its effects on the contractile function of rings from several arteries and veins. A maximal norbormide concentration (50 microM) failed to contract thoracic aorta and carotid artery, whereas in pulmonary artery, abdominal aorta, iliac, caudal, and femoral arteries it induced a contractile effect that was respectively 4.8 +/- 0.6, 18.4 +/- 1.5, 39 +/- 5, 144 +/- 7, and 260 +/- 22% of that induced by 90 mM KCl. In pulmonary, carotid, and iliac arteries, and in thoracic and abdominal aorta, 50 microM norbormide inhibited KCl-induced responses. Norbormide (50 microM) contracted all veins investigated. The effect, expressed as % of KCl-induced contraction, was 121 +/- 25, 154 +/- 14.5, 154 +/- 18.2, 203 +/- 19, and 267 +/- 33 for pulmonary vein, thoracic and abdominal vena cava, iliac and jugular veins, respectively. In jugular vein, as previously shown in rat caudal artery, norbormide contraction was abolished in Ca2+-free medium, was unaffected by the Ca2+ channel blocker nifedipine, and was relaxed by SK&F 96365, a blocker of store-operated Ca2+ channels. In conclusion: i) rat veins represent the main target for contractile norbormide action; ii) in both artery and veins norbormide contractions are generally inversely related to the calibre of the vessel; iii) norbormide-induced contraction is mediated by the same mechanism/s in arteries and veins; iiii) in norbormide-contracted arteries the drug activates both contractile and relaxing mechanisms.     

Effects of HIS1 modifications on the ability of vasoactive intestinal peptide to stimulate adenylate cyclase from rat and human tissues

The importance of the N-terminal His residue of VIP for stimulating adenylate cyclase was appreciated by estimating the intrinsic activity and EC50 of four VIP analogues on membranes from rat lung, liver, brain, anterior pituitary, and pancreas, and on human heart membranes. In all tissue preparations tested except one, the order of efficacy (and often potency) was: VIP greater than (Ac-His1)VIP greater than (Phe1)VIP = (3-Me-His1)VIP greater than (D-His1)VIP. In rat heart membranes, the order of efficacy was somewhat different: VIP greater than (Ac-His1)VIP = (Phe1)VIP greater than (D-His1)VIP greater than (3-Me-His1)VIP. These data demonstrated the key role of His1 in VIP in activating adenylate cyclase. They suggest that a given VIP analogue might act as full agonist in tightly coupled adenylate cyclase systems (such as those of rat lung and liver membranes) whereas the same analogue could not promote full activity in poorly coupled systems (such as that present in rat brain synaptic membranes).     

Age-Related Bidirectional Changes in Neuropeptide Y Peptides in Rat Adrenal Glands, Brain, and Blood

Age-related changes in neuropeptide Y (NPY) regulation were studied in rat adrenal glands, brains, and blood by radioimmunoassay and biochemical characterization using reversed phase HPLC and gel filtration chromatography. NPY immunoreactivity (pmol/g tissue +/- SEM) in rat adrenal glands increased from 7 +/- 1 (6 weeks old) to 1,500 +/- 580 (69 weeks old). Biochemical characterization by HPLC showed that this increase was due to those of NPY and methionine sulfoxide NPY. In contrast, in rat brain, NPY content decreased in an age-dependent manner specifically in striatum, hippocampus, medulla oblongata, and spinal cord and the sulfoxide form was not detected. In rat blood, the circulating level of NPY was high (3-5 pmol/ml plasma +/- SEM) but did not change significantly with age or by adrenal demedullation. Only a small increase of the sulfoxide form of NPY was observed in aged rat plasma. The age-dependent changes in regulation and modification of NPY in adrenal glands and in specific brain areas may have physiological relevance in the regulation of catecholamine release from adrenal glands and some brain functions during aging.     

Monoamine Oxidase Activity of Mitochondria Prepared from Rat Liver and Rat Heart

Abstract: The effect of agents that change the respiratory state of the mitochondrion on tyramine oxidation was investigated. Neither uncoupler nor ADP and P_t in the presence of substrate produced any change in the rate of tyramine oxidation, as judged by direct measurement of tyramine oxidation or by H₂O₂ production. We conclude that previously reported depression of monoamine oxidase activity by stimulated respiration was due to oxygen depletion.     

Kinetics of glucocorticoid interaction with wild-type and variant receptors

Data concerning the short- and longterm effects of ovariectomy on the levels of estrogen binding sites in the rat uterus and liver are presented. The information increases the understanding of the regulation of estrogen receptor synthesis. The circulating estrogen level is suggested to affect receptor synthesis in the uterus and liver differently. Shortly after gonadectomy (2–20h), an elevation in the concentration of cytoplasmic binding sites in the uterus of 35% was observed, whereas no effect was seen in the liver cell. A longer period of time after ovariectomy (2–3 months) caused a reduction in the number of uterine receptor sites by 74%, whereas in the liver an increase of 84% was detected.     

Regional and Subcellular Calmodulin Content of Rat Brain

Calmodulin contents of cortex, cerebellum, striatum, diencephalon, and medulla + pons and of subcellular fractions of each region were determined by radioimmunoassay. The diencephalon had the highest level of calmodulin (48.87 +/- 4.56 micrograms/mg protein), whereas medulla + pons had the lowest level (8.01 +/- 0.84 micrograms/mg protein). In all brain regions, the mitochondrial fraction was richest in calmodulin (from 71 to 227 micrograms/mg protein) whereas other areas contained from 6 to 66 micrograms/mg protein.     

Endothelium-dependent and -independent relaxation of rat aorta induced by extract of Schizophyllum commune

Schizophyllum commune (SC) is widely consumed by Chinese, especially in southern part of China. The aim of the present study was to assess the extract of SC on vascular tone and the mechanisms involved. Experiments were performed on aorta of 18-week-old male Sprague-Dawley rats. Dried SC was extracted with 50% ethanol, 90% ethanol and deionized water, respectively. The effects of SC on the isometric tension of rat aortic rings were measured. Protein expression for the endothelial nitric oxide synthase (eNOS) was also determined in the primarily cultured rat aortic arterial endothelial cells (RAECs). The results showed that the water extract of SC induced a marked relaxation in aortic rings with or without endothelium. After the pretreatments of N^ω-nitro-l-arginine methyl ester, indomethacin, RP-cAMP, and methylene blue, the SC-induced relaxation was significantly decreased. In addition, the contraction due to Ca²⁺ influx and intracellular Ca²⁺ release was also inhibited by SC. Furthermore, expression of the eNOS protein was significantly elevated in RAECs after treatment of SC. In conclusion, the water extract of SC induces an endothelium-dependent and -independent relaxation in rat aorta. The relaxing effect of SC involves the modulation of NO-cGMP-dependent pathways, PGI₂-cAMP-depedent pathways, Ca²⁺ influx though calcium channels and intracellular Ca²⁺ release.     

Determination of Some Molecular Parameters of Tyrosine Hydroxylase From Rat Adrenal, Rat Striatum, and Human Pheochromocytoma

The molecular parameters of tyrosine hydroxylase (EC 1.14.16.2) from rat adrenal, rat striatum, and human pheochromocytoma were determined by combined gel filtration and sucrose gradient ultracentrifugation. The enzyme from rat adrenal has a calculated molecular weight of 228,000, a Stokes radius of 60.9 A, a sedimentation coefficient of 9.10S, and a frictional ratio of 1.39. The enzyme from rat striatum has a calculated molecular weight of 210,000, a Stokes radius of 54.3 A, a sedimentation coefficient of 9.38S, and a frictional ratio of 1.28. Tyrosine hydroxylase from human pheochromocytoma tissue has a calculated molecular weight of 255,000, a Stokes radius of 68.2 A, a sedimentation coefficient of 9.08S, and a frictional ratio of 1.50. These results indicate that the tyrosine hydroxylases from central and peripheral tissue in the rat are quite similar although the human enzyme appears to be significantly larger.     

Cortistatin modulates the expression and release of corticotrophin releasing hormone in rat brain. Comparison with somatostatin and octreotide

Cortistatin (CST) is an endogenous neuropeptide characterized by remarkable structural and functional resemblance to somatostatin (SST), both peptides sharing the ability to bind and activate all five SST receptor subtypes. Evidence is also available showing that CST exerts biological activities independently from SST, perhaps via the activation of specific receptors that remain to be fully characterized at present. Here we have investigated the effects of CST on the gene expression and release of corticotrophin releasing hormone (CRH) from rat hypothalamic and hippocampal explants; moreover, we compared the effects of CST with those of SST and octreotide (OCT) in these models. We found that: (i) CST inhibits the expression and release of CRH from rat hypothalamic and hippocampal explants under basal conditions as well as after CRH stimulation by well known secretagogues; (ii) SST does not modify basal CRH secretion from the hypothalamus or the hippocampus, while it is able to reduce KCl-stimulated CRH release from both brain areas; (iii) OCT inhibits both basal and KCl-induced CRH secretion from rat hypothalamic explants, while it has no effect on CRH release from the hippocampus, either under basal conditions or after stimulation by high K(+) concentrations; (iv) at variance with CST; SST and OCT have not effect whatsoever on veratridine-induced CRH release from the hypothalamus. In conclusion the present findings provide in vitro evidence in support of the hypothesis that CST plays a role in the regulation of endocrine adaptive responses to stress.