冠心病外周血IL-7表达变化对机体免疫应答的影响及可能机制

目的探讨冠状动脉粥样硬化性心脏病(冠心病)外周血白细胞介素(IL)-7表达变化对机体免疫应答的影响及可能机制。方法选取稳定型心绞痛患者44例、不稳定型心绞痛患者78例、急性心肌梗死患者42例;另取体检的健康人群40例为正常对照组。流式细胞术检测T细胞表面黏蛋白结构域的分子(Tim)3水平,酶联免疫吸附试验检测血清IL-7水平。体外培养外周血单核细胞,重组IL-7刺激12 h后检测T细胞表面Tim3水平;通过Western印迹法检测IL-7信号通路相关分子的表达水平。结果稳定型心绞痛组、不稳定型心绞痛组、急性心肌梗死组外周血Tim3阳性细胞占CD4^+T细胞的比例明显高于正常对照组,急性心肌梗死组外周血Tim3阳性细胞占CD4^+T细胞的比例明显高于稳定型心绞痛组、不稳定型心绞痛组(P<0.05)。不稳定型心绞痛组、急性心肌梗死组外周血Tim3阳性细胞占CD8+T细胞的比例明显高于正常对照组,急性心肌梗死组外周血Tim3阳性细胞占CD8+T细胞的比例明显高于稳定型心绞痛组、不稳定型心绞痛组(P<0.05)。急性心肌梗死组血清IL-7水平明显高于正常对照组(P<0.01);稳定型心绞痛组和不稳定型心绞痛组血清IL-7水平与正常对照组之间差异无统计学意义(P>0.05);血清IL-7浓度与Tim3+CD4^+T、CD8+T细胞比例均无相关性。急性心肌梗死组重组IL-7刺激12 h的CD4^+T细胞表面Tim3表达水平较未刺激者明显升高(P<0.05)。正常对照组、急性心肌梗死组重组IL-7刺激12 h的CD8^+T细胞表面Tim3表达水平较未刺激者明显升高(P<0.05)。重组IL-7刺激后p-STAT-5蛋白相对表达量明显高于未刺激的细胞(P<0.01);重组IL-7刺激后SOCS3蛋白相对表达量明显高于未刺激的细胞(P<0.05)。结论IL-7可上调Tim3表达,在冠心病发生、发展中发挥抑制炎症应答的作用。     

原发性肝癌患者CD4+CD25+调节性T细胞及转化生长因子β1检测

目的探讨检测原发性肝癌患者外周血CD4+CD25+调节性T细胞(Treg)及血清转化生长因子(TGF)-β1的临床意义。方法应用流式细胞学方法和酶联免疫吸附测定方法分别检测原发性肝癌患者32例、转移性肝癌患者25例、健康体检者30例的外周血Treg占总CD4+T细胞的比例和血清TGF-β1浓度。结果原发性肝癌、转移性肝癌患者外周血Treg占总CD4+T细胞的比例与对照组比较均明显升高,差异有统计学意义(P<0.01);原发性肝癌患者外周血Treg占总CD4+T细胞的比例较转移性肝癌患者亦明显升高,差异有统计学意义(P<0.05)。原发性肝癌、转移性肝癌患者血清TGF-β1浓度与对照组比较均明显升高,差异有统计学意义(P<0.01);原发性肝癌患者血清TGF-β1浓度较转移性肝癌患者亦明显升高,差异有统计学意义(P<0.01)。相关分析显示,原发性肝癌患者外周血Treg占总CD4+T细胞的比例与病理分期、血清TGF-β1浓度呈正相关(r=0.762、r=0.698,P<0.01),与Karnofsky功能状态(KPS)评分呈负相关(r=-0.642,P<0.01)。结论原发性肝癌患者外周血Treg比例明显升高,且与血清TGF-β1浓度、病理分期和KPS评分具有一定的相关性。检测原发性肝癌患者外周血Treg占总CD4+T细胞的比例可能有助于评估原发性肝癌患者的病情进展及判断其预后。     

慢性HBV感染者外周血CXCR5~+CD4~+Tfh细胞的测定及其与FoxP3~+Treg细胞的相关性

目的:探讨慢性乙型肝炎病毒(hepatitis Bvirus,HBV)感染不同阶段患者外周血CD4+T淋巴细胞中CD4+CXCR5+Tfh细胞及CD4+CD25+FoxP3+Treg细胞的百分比及其意义.方法:应用流式细胞术检测15例慢性无症状HBV携带者(chronic asymptomatic HBV carriers,AsC)、42例慢性乙型肝炎(chronic hepatitisB,CHB)患者(HBeAg阳性25例、HBeAg阴性17例)、11例非活动性HBsAg携带者(inactive HBsAg carriers,InC)外周血CD4+CXCR5+Tfh细胞及CD4+CD25+FoxP3+Treg细胞占CD4+T淋巴细胞的百分比,并与15例健康对照(healthycontrol,HC)进行比较.结果:AsC、HBeAg(+)CHB、HBeAg(-)CHB组外周血CD4+CXCR5+Tfh细胞占CD4+T淋巴细胞的比例分别为17.66(15.34%-20.56%),21.95(19.60%-26.32%),22.33(17.58%-24.85%),显著高于HC组的13.67(9.80%-15.32%),差异具有统计学意义(P<0.001).与AsC及InC组的16.11(12.33%-19.73%)相比,HBeAg(+)、HBeAg(-)CHB组外周血CD4+CXCR5+Tfh细胞占CD4+T淋巴细胞的比例显著升高(P<0.05).此外,AsC组外周血CD4+CD25+FoxP3+Treg细胞占CD4+T淋巴细胞的比例为7.70(6.35%-9.13%),显著高于HC组的6.53(5.54%-7.35%),P<0.05.HBeAg(+)CHB组外周血CD4+T淋巴细胞中CD4+CD25+FoxP3+Treg细胞的频率为7.52(6.09%-8.49%),与AsC组相比呈降低的趋势.外周血CD4+CXCR5+Tfh细胞占CD4+T淋巴细胞的比例与HBVDNA载量呈负性相关(r=-0.275,P<0.05);而与血清ALT水平、HBsAg滴度无相关性.结论:CD4+CXCR5+Tfh细胞可能参与了慢性HBV感染所介导的免疫反应,外周血CD4+CD25+FoxP3+Treg细胞及CD4+CXCR5+Tfh细胞的消长可能与疾病的活动性相关.     

缬沙坦对不稳定型心绞痛患者CD4~+ CD28~- T淋巴细胞及预后的影响

目的研究缬沙坦对不稳定型心绞痛患者外周血中CD4+CD28-T淋巴细胞的比例及其相关细胞因子IFN-γ的影响。方法将85例经冠状动脉造影证实的不稳定型心绞痛患者随机分为常规治疗组和缬沙坦治疗组。采用流式细胞仪检测42例常规治疗组和43例缬沙坦治疗组患者治疗前及治疗6个月后外周血中CD4+CD28-T淋巴细胞的数量,以酶联免疫吸附试验(ELISA法)测定治疗前后血浆中干扰素-γ(IFN-γ)水平,并同时观察两组患者出院后6个月内因不稳定型心绞痛再次入院、急性心肌梗死、血运重建及死亡等主要心血管事件(MACE)情况。结果两组患者在治疗6个月后CD4+CD28-T淋巴细胞的比例及血浆中IFN-γ水平均较治疗前下降(P<0.05),缬沙坦治疗组下降较常规治疗组更为明显(P<0.05)。缬沙坦治疗组6个月内的主要心血管事件显著减少(P<0.05)。结论缬沙坦可能通过降低不稳定型心绞痛患者外周血中CD4+CD28-T淋巴细胞的比例及血浆中IFN-γ的水平,从而达到稳定斑块,改善预后的作用。     

乙型肝炎肝硬化患者外周血调节性T细胞频率及血清IL-1β、IL-6和IL-10水平的变化

目的检测未抗病毒治疗的乙型肝炎肝硬化患者外周血调节性T细胞(Treg细胞)及其亚群频率和血清IL-1β、IL-6、IL-10水平,以探讨乙型肝炎肝硬化患者免疫功能的变化。方法在20例健康对照人群、17例慢性乙型肝炎(CHB)患者和38例乙型肝炎肝硬化(LC)患者,采用流式细胞仪检测外周血CD4+CD25+Foxp3(+Treg)细胞频率、CD4+CD39+Foxp3(+CD39+Treg)细胞和CD4+CTLA-4+Foxp3(+CTLA-4+Treg)细胞频率;采用ELISA法检测血清IL-1β、IL-6和IL-10水平。结果 LC患者Treg细胞频率、CD39+Treg细胞频率、CTLA-4+Treg细胞频率、血清IL-1β、IL-6和IL-10水平均高于正常人(P均<0.01)和CHB患者(P<0.05或P<0.01);失代偿期LC患者Treg细胞频率、CD39+Treg细胞频率、IL-6水平高于代偿期患者(P均<0.01);LC患者Treg细胞频率与CD39+Treg细胞频率(r=0.474,P<0.01)、CTLA-4+Treg细胞频率均呈正相关(r=0.330,P<0.05),Treg细胞频率(r=0.381,P<0.05)、CD39+Treg细胞频率(r=0.333,P<0.05)与TBil呈正相关,Treg细胞频率(r=-0.549,P<0.01)、CD39+Treg细胞频率(r=-0.437,P<0.01)、CTLA-4+Treg细胞频率(r=-0.368,P<0.01)与PTA呈负相关,CD39+Treg细胞频率与AST呈正相关(r=0.406,P<0.05)。结论 Treg细胞及其亚群频率和IL-1β、IL-6、IL-10水平的变化可作为临床初始治疗的乙型肝炎肝硬化患者辅助检查指标之一。     

高龄肝癌患者CD4+CD25+调节性T细胞及转化生长因子-β1检测的临床意义

目的 探讨检测老年原发性肝癌患者外周血CD4+ CD25+调节性T细胞(Treg)及血清转化生长因子(TGF)-β1的临床意义. 方法 应用流式细胞学方法和酶联免疫吸附测定方法分别检测80岁以上老年健康者20例、原发性肝癌患者22例、转移性肝癌患者25例外周血Treg占总CD4+T细胞的比例和血清TGF-β1浓度. 结果 老年原发性肝癌、转移性肝癌患者外周血Treg占总CD4+T细胞的比例与老年健康对照组比较均明显升高,差异有统计学意义(P＜0.01).老年原发性肝癌患者外周血T reg总CD4+T细胞比例较老年转移性肝癌患者亦明显升高,差异有统计学意义(P＜0.05).老年原发性肝癌、转移性肝癌患者血清TGF-β1浓度与老年健康对照组比较均明显升高,差异有统计学意义(P＜0.01).老年原发性肝癌患者血清TGF-31浓度较老年转移性肝癌患者亦明显升高,差异有统计学意义(P＜0.01).相关分析显示,原发性肝癌患者外周血Treg占总CD4+T细胞的比例与病理分期、血清TGF-β1浓度呈正相关(r=0.782、r=0.698,P＜0.01),与Karnofsky功能状态(KPS)评分负相关(r=-0.643,P＜0.01). 结论 高龄原发性肝癌患者外周血Treg比例明显升高,且与血清TGF-β1浓度、病理分期及KPS评分具有一定的相关性.检测老年原发性肝癌患者外周血Treg占总CD4+T细胞的比例,可能有助于评估老年原发性肝癌患者病情进展情况及判断其预后.     

L-选择素在系统性红斑狼疮患者外周血CD4~+CD25~+T淋巴细胞的表达及其与Foxp3的相关性

目的了解黏附分子L-选择素(L-selectin,CD62L)在系统性红斑狼疮(systemic lupus erythematosus,SLE)患者外周血CD4+CD25+T淋巴细胞的表达,及其与CD4+CD25+Treg细胞转录因子Foxp3的相关性。方法用流式细胞仪检测68例SLE患者外周血CD4+、CD4+CD25+T淋巴细胞CD62L和Foxp3的表达。根据SLEDAI评分,68例SLE患者中活动组36例,稳定组32例;健康对照组35人。结果活动组SLE患者外周血CD4+CD25+CD62L+T淋巴细胞为(1.71±1.60)%,低于对照组的(5.87±3.03)%(P0.01)和稳定组的(4.91±1.69)%(P0.01),差异具有显著性意义;且与SLEDAI呈负相关(r=-0.695,P=0.000),与补体C3水平呈正相关(r=0.522,P=0.000)。活动组SLE患者外周血CD4+CD25+CD62L+Foxp3+T淋巴细胞为(1.06±0.47)%,低于对照组的(3.17±0.87)%(P0.01)和稳定组的(3.46±1.15)%(P0.01),差异有显著性意义。CD4+T淋巴细胞CD62L的表达与CD4+CD25+T淋巴细胞CD62L和Foxp3的表达呈负相关(r=-0.689,P=0.000;r=-0.568,P=0.000);CD4+CD25+T淋巴细胞CD62L的表达与Foxp3的表达呈正相关(r=0.891,P=0.000)。结论CD62L在SLE患者外周血CD4+CD25+T的低表达及与Foxp3表达密切相关,可能在SLE发病中起着重要作用。     

先天性心脏病患者免疫因子Th17/Treg失衡与肺动脉高压的关系

目的:探讨患者外周血中Th17细胞、CD4+D25+FoxP3+调节性T细胞(Treg)的变化及意义。方法:75例先天性心脏病(CHD)合并肺动脉高压(PAH)患者,分为轻度肺动脉高压组(28例)、中度肺动脉高压组(32例)及重度肺动脉高压组(15例),20例健康体检者作为对照组。采用流式细胞分析法检测外周血中Th17细胞、Treg细胞占CD4+T细胞的比例,分析Th17细胞与Treg细胞的比例与肺动脉压的相关性。结果:Th17/CD4+T细胞比例、Treg/CD4+T细胞的比例和Th17/Treg细胞比值,两组间差异具有统计学意义(P<0.05),随着肺mPAP的增加,Th17/CD4+T细胞比例明显升高;Treg/CD4+T细胞的比例明显下降;Th17/Treg细胞比值显著升高。mPAP与Th17/Treg比值呈显著正相关(r=0.95,P<0.05)。结论:先天性心脏病合并肺动脉高压患者外周血中存在Th17/Treg失衡,且与肺动脉高压程度呈正相关,Th17/Treg失衡可能参与了肺动脉高压的发生发展。     

冠心病患者外周血T细胞亚群和自然杀伤细胞的变化

目的:探讨外周血CD4+T细胞、CD8+T细胞、CD4+CD25+调节性T细胞、自然杀伤细胞(NK细胞)水平与冠状动脉(冠脉)病变程度的关系.方法:选择收治的冠心病或疑诊为冠心病行冠脉造影的患者126例,按临床表现,冠脉造影诊断分为4组:急性心肌梗死(AMI)组34例、不稳定型心绞痛(UAP)组49例、稳定型心绞痛(SAP)组20例和冠脉造影正常胸痛综合征组(对照组)23例,采用流式细胞术测定4组患者外周血CD4+T细胞、CD8+T细胞、CD4+CD25+调节性T细胞(分为CD4+CD25+T细胞和CD4+CD25++T细胞)、NK(CD3-CD16+CD56+)细胞亚群占淋巴细胞的比例.同时分析各组T细胞亚群和NK细胞水平与Gensini积分相关性.结果:AMI组和UAP组CD4+T细胞较对照组显著升高,而CD8+T细胞、CD4+CD25+调节性T细胞、NK细胞显著降低(P＜0.05);SAP组较对照组NK细胞显著升高(P＜0.05).CD8+T细胞,CD4+CD25+T细胞,CD4+CD25++T细胞与Gensini积分均呈负相关性(P＜0.05).结论:CD4+升高,CD8+T细胞、CD4+CD25+调节性T细胞、NK细胞降低可能反映了冠心病患者异常增强的免疫反应及免疫调节受损,其参与了动脉粥样硬化的发生发展.随着免疫调节受损加重,冠脉病变的数最和狭窄程度可能加重.     

激素抵抗性哮喘患者外周血CD4+CD25+Foxp3+调节性T细胞及IL-10、TGF-β1的变化及意义

目的 观察激素抵抗性哮喘(SRA)患者外周血CD4+CD25+Foxp3+调节性T细胞(Treg)及白介素10(IL-10)、转化生长因子β1(TGF-β1)的变化,分析其在SRA发病机制中的作用.方法 采用流式细胞术检测40例SRA患者(激素抵抗组)外周血单个核细胞CD4+CD25+Foxp3+ Treg数目,并计算CD4+CD25+Foxp3+ Treg占CD4+T淋巴细胞的百分比;酶联免疫吸附试验(ELISA)法检测其血清IL-10、TGF-β1水平,并与激素敏感性患者(激素敏感组,46例)及正常体检者(正常组,30例)进行对比.结果 激素抵抗组患者外周血CD4+CD25+Foxp3+Treg占CD4+T淋巴细胞的百分比、CD4+CD25+Foxp3+Treg绝对值及血清IL-10、TGF-β1水平均明显低于激素敏感组与正常组(P＜0.01,P＜0.05);激素敏感组患者外周血CD4+CD25+Foxp3+Treg占CD4+T淋巴细胞的百分比、CD4+CD25+Foxp3+Treg绝对值及血清TGF-β1水平明显低于正常组(P＜0.01,P＜0.05),血清IL-10无明显差异(P＞0.05);CD4+CD25+Foxp3+Treg/CD4+T及CD4+CD25+Foxp3+Treg绝对数均与血清IL-10、TGF-β1水平呈明显正相关(P＜0.01).结论 SRA患者外周血CD4+CD25+Foxp3+ Treg数目减少及IL-10、TGF-β1含量减低可能与SRA的发生、发展有关.     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Serological survey of HIV and syphilis in pregnant women in Madagascar

Objectives Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy. Methods Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays. Results Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum. Conclusions Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.