阿片受体介导大鼠海马内脑啡肽对细胞免疫功能的调节

以刀豆蛋白Ａ（ＣｏｎＡ）刺激的脾淋巴细胞增殖活性及自然杀伤细胞（ＮＫｃｅｌ）活性为细胞免疫功能检测指标,观察了阿片受体阻断剂纳洛酮（Ｎａｌｏｘｏｎｅ,ＮＬＸ）对大鼠海马内微量注射甲硫脑啡肽所致的免疫功能增强作用的影响。结果发现：（１）海马内微量注射白细胞介素１（ＩＬ１）诱导剂（细菌内毒素）脂多糖（ｌｉｐｏｐｏｌｙｓａｃｈａｒｉｄｅ,ＬＰＳ,５０ｎｇ／１μｌ）可降低机体免疫功能。（２）双侧海马内预先注射甲硫脑啡肽（ＭＥＮＫ,浓度：１０μｇ／μｌ）各１μｌ,可阻止脑内ＬＰＳ降低免疫功能的作用。（３）脑啡肽的这种作用可被阿片受体阻断剂纳洛酮（１０μｇ／１μｌ）阻断。（４）海马内单纯注射纳洛酮对机体免疫功能也起抑制作用。上述结果提示,海马内脑啡肽对免疫功能的增强作用是通过阿片受体介导的。     

尾核阿片μ受体参与电针及皮层SmⅠ区对束旁核伤害性反应的抑制

为探索尾核（ｃａｕｄａｔｅｎｕｃｌｅｕｓ,Ｃｄ）是否参与电针及皮层体感运动Ⅰ区（ｓｅｎｓｏｒｉｍｏｔｏｒａｒｅａⅠｏｆｔｈｅｃｅｒｅｂｒａｌｃｏｒｔｅｘ,ＳｍⅠ）对束旁核（ｐａｒａｆａｓｃｉｃｕｌａｒｎｕｃｌｅｕｓ,Ｐｆ）神经元伤害性反应的调节,以及Ｃｄ中阿片受体是否参与并通过何种受体参与这一调节,本实验用Ｃｄ头部化学毁损及微量注射阿片受体拮抗剂的方法,观察到Ｃｄ毁损前电针及兴奋皮层均可抑制Ｐｆ的伤害性反应,而毁损后这种抑制效应消失;注射纳洛酮或阿片μ受体拮抗剂βＦＮＡ后,电针及兴奋皮层ＳｍⅠ区对Ｐｆ伤害性反应的抑制作用被取消,而分别注射δ和κ受体拮抗剂ＩＣＩ１７４,８６４和ｎｏｒＢＮＩ则不产生影响。基于已证明大脑皮层参与电针对Ｐｆ伤害性反应的调节,本结果提示：Ｃｄ参与针刺镇痛中皮层ＳｍⅠ区对Ｐｆ神经元伤害性反应的抑制,Ｃｄ中阿片肽主要通过μ受体参与抑制作用。     

脑室注射白细胞介素2抑制脾交感神经活动

本文应用电生理方法研究了中枢应用白细胞介素２对脾交感神经放电活动的影响。用ｕｒｅｔｈａｎｅ α－ｃｈｌｏｒａｌｏｓｅ麻醉Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ大鼠,第三脑室微量注射基因重组人ＩＬ－２３００Ｕ,观察到脾交感神经冲动数减少。在ＩＬ－２注射前后应用阿片受体阻断剂纳洛酮,均可阻断这种效应,但单独应用Ｎａｌ对脾神经兴奋性没有影响。实验中未观察到ＩＬ－２对体温和动脉血压的影响。说明ＩＬ－２抑制脾神经电活     

导水管周围灰质参与电针对防御反应的抑制效应

在清醒家兔中,双侧损毁导水管周围灰质(PAG)的腹侧部或在双侧PAG腹侧部微量注射阿片受体拮抗剂纳洛酮,可明显阻断电针对刺激下丘脑背内侧区引起的防御反应的抑制效应。双侧损毁PAG腹侧部或在双侧PAG腹侧部微量注射纳洛酮,也都能减低直接兴奋弓状核区对防御反应的抑制作用的程度,在PAG 腹侧部微量注射阿片受体激动剂吗啡则可抑制刺激下丘脑引起的防御反应。以上实验结果提示,PAG 腹侧部的阿片受体可能参与电针抑制防御反应的机制。本文讨论了电针可能激活弓状核的内啡肽神经元并激活PAG 腹侧部的阿片受体而对防御反应发生抑制作用的可能性。     

白细胞介素－2中枢镇痛作用途径的探讨

抗ＩＬ－２受体α亚基的单克隆抗体不能阻断ＩＬ－２的中枢镇痛作用,以及丧失与ＩＬ－２受体β亚基结合能力的ＩＬ－２突变体仍具有提高大鼠痛阈的能力,这表明ＩＬ－２的中枢镇痛作用并不是通过ＩＬ－２受体所介导,亦表示ＩＬ－２的免疫和镇痛作用是通过不同的受体途径实现的。加之内源性阿片肽与ＩＬ－２分子有着共同的抗原决定基和结构相似性,提示ＩＬ－２可以与阿片受体直接结合产生中枢镇痛效应。从放射免疫法测定的ＩＬ－２侧脑室注射后不同时间大鼠脑内不同核团的内源性阿片肽含量,推测ＩＬ－２的中枢镇痛作用可能还与弓状核、室旁核、蓝斑等核团的β－ＥＰ和ＬＥＫ有关。     

内皮素-1对培养新生大鼠心肌细胞原癌基因c-fos表达的诱导

本实验用无血清的培养新生大鼠心肌细胞,探讨内皮素１（ＥＴ１）对原癌基因ｃｆｏｓ表达的作用。结果显示：ＥＴ１可显著诱导ｃｆｏｓ的表达,其表达的高峰在３０ｍｉｎ,２ｈ恢复到正常水平,并呈剂量依赖性反应和被ＥＴＡ的特异性受体拮抗剂ＢＱ１２３所阻断;蛋白激酶Ｃ（ＰＫＣ）激动剂ＰＭＡ可诱导ｃｆｏｓ表达,而ＰＫＣ抑制剂Ｓｔａｕｒｏｓｐｏｒｉｎｅ则可阻断ＥＴ１诱导的ｃｆｏｓ表达;钙通道阻断剂硝苯吡啶预处理心肌细胞对ＥＴ１诱导的心肌细胞的ｃｆｏｓ表达无明显的作用。这些结果提示,ＥＴ１诱导ｃｆｏｓ表达是通过ＥＴＡ受体介导的,ＰＫＣ在此过程中起重要作用。     

中枢应用β-内啡肽对大鼠血浆唾液酸水平的影响以及与免疫功能的关系

实验选择体重２００－２５０ｇ健康Ｗｉｓｔａｒ大鼠６４只,采用麻醉大鼠中枢微量注射,分光光测定法及免疫组织化学法,研究侧脑室,弓状核（ＡＲＣ）区注射β－内啡肽（β－ＥＰ）对大鼠血浆唾液酸（ＳＡ）水平的影响及与免疫功能的关系,结果表明：（１）侧脑室注射β－ＥＰ可明显降低血浆ＳＡ水平;（２）血浆ＳＡ水平在ＡＲＣ区注射β－ＥＰ后明显降低,此效应可被Ｍ胆碱受体阻断剂阿托品或切断双侧颈迷走神经所阻断;（３）Ａ     

兔孤束核腹外侧区微量注射谷氨酸钠及甘氨酸对弓状核诱发电位的影响

实验在６６只麻醉、制动,断双侧颈迷走神经和人工通气的家兔上进行。通过微量注射神经元胞体兴奋剂谷氨酸钠和神经元胞体抑制剂甘氨酸,改变孤束核腹外侧区神经元兴奋活动,探讨对下丘脑弓状核诱发电位的影响及其可能的机制和意义。实验结果如下：（１）孤束核腹外侧区微量注射谷氨酸钠,可使膈神经放电显著增加和使弓状核诱发电位Ｐ２及Ｎ２波幅显著降低;而微量注射甘氨酸则使膈神经放电显著减少和使弓状核诱发电位Ｐ２及Ｎ２波幅显著增大。（２）静脉注射纳洛酮对谷氨酸钠引起的膈神经放电兴奋效应无明显影响,但能翻转谷氨酸钠对弓状核诱发电位Ｐ２及Ｎ２波幅的抑制效应。提示：孤束核腹外侧区呼吸神经元的兴奋活动可扩散至弓状核,并对弓状核诱发电位产生影响,此影响可能是由内源性阿片系统参与而实现的。     

脊髓中P物质参与电针镇痛的研究

本研究发现,低频（２Ｈｚ）电针刺激时大鼠脊髓中Ｐ物质免疫活性（ＳＰ－ｉｒ）含量减少,中频（１５Ｈｚ）、高频（１００Ｈｚ）和变频（２／１５Ｈｚ）刺激时ＳＰ－ｉｒ含量增多。脊髓蛛网膜下腔（ｉ．ｔ．）注射非肽类ＳＰ（ＮＫＩ）受体拮抗剂ＣＰ９６３４５和ＲＰ６７５８０均能阻断中频、高频和变频的电针镇痛。ｉ．ｔ．注射阿片拮抗剂纳洛酮阻断低频和中频刺激时ＳＰ－ｉｒ含量的变化。结果提示,脊髓ＳＰ－ｉｒ在低频时释放     

胃动素对大鼠下丘脑胃牵张敏感神经元和胃运动的影响(英文)

目的:研究胃动素对下丘脑弓状核胃牵张敏感神经元放电活动和胃运动的影响。方法:采用4管玻璃微电极细胞外记录胃动素对大鼠弓状核胃牵张敏感神经元活动,采用胃内置传感器观察胃动素对对清醒大鼠胃运动的影响。结果:65.5%的弓状核神经元为胃扩张敏感性神经元,其中55.6%为胃扩张兴奋性神经元,44.4%为抑制性神经元。胃扩张刺激后兴奋性神经元的放电频率显著增加(P<0.01),而抑制性神经元的放电频率显著降低(P<0.01)。弓状核内微量注射胃动素,70%的兴奋性神经元在胃扩张刺激后表现为兴奋作用,17.5%的神经元表现为抑制作用,并且放电频率显著增加(P<0.05)。同样,在抑制性神经元中,65.6%在注射胃动素后引起电活动增强,放电频率显著降低(P<0.05)。而胃动素受体拮抗剂GM-109可以完全阻断这种由胃动素诱导的兴奋作用,提示,胃动素在弓状核通过其特异性受体调控神经元活动。在胃运动实验中,弓状核微量注射胃动素后,胃运动的收缩频率和幅度都显著增加(P<0.05);同时,这种兴奋作用也可被GM-109阻断。结论:研究证实了弓状核胃动素神经元接收来自胃感受器的外周躯体感觉传入神经的冲动,并通过某些下级核团通路发挥...     

The dynamic relationship between mu and kappa opioid receptors in body temperature regulation

Previous studies demonstrated that intracerebroventricular (icv) injection of a kappa opioid receptor agonist decreased, and a mu agonist increased, body temperature (Tb) in rats. A dose-response study with the selective kappa antagonist nor-binaltorphimine (nor-BNI) showed that a low dose (1.25 nmol, icv) alone had no effect, although a high dose (25 nmol, icv) increased Tb. It was hypothesized that the hyperthermia induced by nor-BNI was the result of the antagonist blocking the kappa opioid receptor and releasing its inhibition of mu opioid receptor activity. To determine whether the Tb increase caused by nor-BNI was a mu receptor-mediated effect, we administered the selective mu antagonist CTAP (1.25 nmol, icv) 15 min after nor-BNI (25 nmol, icv) and measured rectal Tb in unrestrained rats. CTAP significantly antagonized the Tb increase induced by icv injection of nor-BNI. Injection of 5 or 10 nmol of CTAP alone significantly decreased the Tb, and 1.25 nmol of nor-BNI blocked that effect, indicating that the CTAP-induced hypothermia was kappa-mediated. The findings strongly suggest that mu antagonists, in blocking the basal hyperthermia mediated by mu receptors, can unmask the endogenous kappa receptor-mediated hypothermia, and that there is a tonic balance between mu and kappa opioid receptors that serves as a homeostatic mechanism for maintaining Tb.     

NPY-induced feeding: pharmacological characterization using selective opioid antagonists and antisense probes in rats

The ability of neuropeptide Y to potently stimulate food intake is dependent in part upon the functioning of mu and kappa opioid receptors. The combined use of selective opioid antagonists directed against mu, delta or kappa receptors and antisense probes directed against specific exons of the MOR-1, DOR-1, KOR-1 and KOR-3/ORL-1 opioid receptor genes has been successful in characterizing the precise receptor subpopulations mediating feeding elicited by opioid peptides and agonists as well as homeostatic challenges. The present study examined the dose-dependent (5-80 nmol) cerebroventricular actions of general and selective mu, delta, and kappa1 opioid receptor antagonists together with antisense probes directed against each of the four exons of the MOR-1 opioid receptor gene and each of the three exons of the DOR-1, KOR-1, and KOR-3/ORL-1 opioid receptor genes upon feeding elicited by cerebroventricular NPY (0.47 nmol, 2 ug). NPY-induced feeding was dose-dependently decreased and sometimes eliminated following pretreatment with general, mu, delta, and kappa1 opioid receptor antagonists. Moreover, NPY-induced feeding was significantly and markedly reduced by antisense probes directed against exons 1, 2, and 3 of the MOR-1 gene, exons 1 and 2 of the DOR-1 gene, exons 1, 2, and 3 of the KOR-1 gene, and exon 3 of the KOR-3/ORL-1 gene. Thus, whereas the opioid peptides, beta-endorphin and dynorphin A(1-17) elicit feeding responses that are respectively more dependent upon mu and kappa opioid receptors and their genes, the opioid mediation of NPY-induced feeding appears to involve all three major opioid receptor subtypes in a manner similar to that observed for feeding responses following glucoprivation or lipoprivation.     

Spinal administration of selective opioid antagonists in amphibians: evidence for an opioid unireceptor

In mammals, opioids act by interactions with three distinct types of receptors: mu, delta, or kappa opioid receptors. Using a novel assay of antinociception in the Northern grass frog, Rana pipiens, previous work demonstrated that selective mu, delta, or kappa opioids produced a potent antinociception when administered by the spinal route. The relative potency of this effect was highly correlated to that found in mammals. Present studies employing selective opioid antagonists, beta-FNA, NTI, or nor-BNI demonstrated that, in general, these antagonists were not selective in the amphibian model. These data have implications for the functional evolution of opioid receptors in vertebrates and suggest that the tested mu, delta, and kappa opioids mediate antinociception via a single type of opioid receptor in amphibians, termed the unireceptor.     

In-vitro investigation of oxazol and urea analogues of morphinan at opioid receptors

A series of 2-amino-oxazole (7 and 8) analogs and 2-one-oxazole analogs (9 and 10) were synthesized from cyclorphan (1) or butorphan (2) and evaluated in-vitro by their binding affinity at mu, delta, and kappa opioid receptors and compared with their 2-aminothiozole analogs 5 and 6. Ligands 7-10 showed decreased affinities at kappa and mu receptors. Urea analogs (11-14) were also prepared from 2-aminocyclorphan (3) or 2-aminobutorphan (4) and evaluated in-vitro by their binding affinity at mu, delta, and kappa opioid receptors. The urea derived opioids retained their affinities at mu receptors while showing increased affinities at delta receptors and decreased affinities at kappa receptors. Functional activities of these compounds were measured in the [35S]GTPgammaS binding assay, illustrating that all of these ligands were kappa agonists. At the mu receptor, compounds 11 and 12 were mu agonist/antagonists.     

Reciprocal opioid-opioid interactions between the ventral tegmental area and nucleus accumbens regions in mediating mu agonist-induced feeding in rats

Feeding elicited by the mu-selective agonist, [D-Ala2, M-Phe4, Gly-ol5]-encephalin administered into the nucleus accumbens is blocked by accumbal pre-treatment with mu, delta1, delta2 and kappa, but not mu1 opioid antagonists. Correspondingly, mu-agonist-induced feeding elicited from the ventral tegmental area is blocked by ventral tegmental area pre-treatment with mu and kappa, but not delta opioid antagonists. A bi-directional opioid-opioid feeding interaction has been firmly established such that mu-agonist-induced feeding elicited from the ventral tegmental area is blocked by accumbal naltrexone, and that accumbal mu-agonist-induced feeding is blocked by naltrexone pre-treatment in the ventral tegmental area. To determine which opioid receptor subtypes mediate the regional bi-directional opioid-opioid feeding interactions between these two sites, the present study examined the dose-dependent ability of either general (naltrexone), mu (beta-funaltrexamine), kappa (nor-binaltorphamine) or delta (naltrindole) opioid antagonists administered into one site to block mu-agonist-induced feeding elicited from the other site. General, mu and kappa, but not delta opioid receptor antagonist pre-treatment in the ventral tegmental area dose-dependently reduced mu-agonist-induced feeding elicited from the nucleus accumbens. General, mu and delta, and to a lesser degree kappa, opioid receptor antagonist pre-treatment in the nucleus accumbens dose-dependently reduced mu-agonist-induced feeding elicited from the ventral tegmental area. Thus, multiple, but different opioid receptor subtypes are involved in mediating opioid-opioid feeding interactions between the nucleus accumbens and ventral tegmental area regions.     

Structure-activity relationship studies of carboxamido-biaryl ethers as opioid receptor antagonists (OpRAs). Part 1

A structurally unique and new class of opioid receptor antagonists (OpRAs) that bear no structural resemblance with morphine or endogenous opioid peptides has been discovered. A series of carboxamido-biaryl ethers were identified as potent receptor antagonists against mu, kappa and delta opioid receptors. The structure-activity relationship indicated para-substituted aryloxyaryl primary carboxamide bearing an amine tether on the distal phenyl ring was optimal for potent in vitro functional antagonism against three opioid receptor subtypes.     

Characterization of opioid receptors on isolated canine gallbladder smooth muscle cells

Smooth muscle cells were isolated from the fundus of the canine gallbladder and examined for the presence of opioid receptors. The cells contracted in a concentration-dependent manner in response to three opioid peptides (Met-enkephalin, dynorphin1-13 and Leu-enkephalin), which are known derivatives of opioid precursors present in myenteric neurons of the gut. The order of potency was Met-enkephalin greater than dynorphin1-13 greater than Leu-enkephalin. The contractile response to opioid agonists was selectively inhibited by opioid antagonists (naloxone and Mr2266) but not by muscarinic, CCK/gastrin or tachykinin antagonists. Equivalent responses to the three opioid peptides exhibited differential sensitivity to preferential antagonists of mu (naloxone) and kappa (Mr2266) opioid receptors consistent with the presence of the three main types of opioid receptors (mu, delta and kappa) on canine gallbladder muscle cells.     

14-O-Heterocyclic-substituted naltrexone derivatives as non-peptide mu opioid receptor selective antagonists: Design,synthesis, and biological studies

Mu opioid receptor antagonists have clinical utility and are important research tools. To develop non-peptide and highly selective mu opioid receptor antagonist, a series of 14-O-heterocyclic-substituted naltrexone derivatives were designed, synthesized, and evaluated. These compounds showed subnanomolar-to-nanomolar binding affinity for the mu opioid receptor. Among them, compound 1 exhibited the highest selectivity for the mu opioid receptor over the delta and kappa receptors. These results implicated an alternative ‘address’ domain in the extracellular loops of the mu opioid receptor.     

High-affinity carbamate analogues of morphinan at opioid receptors

A series of carbamate analogues were synthesized from levorphanol (1a), cyclorphan (2a) or butorphan (3a) and evaluated in vitro for their binding affinity at mu, delta, and kappa opioid receptors. Functional activities of these compounds were measured in the [(35)S]GTPgammaS binding assay. Phenyl carbamate derivatives 2d and 3d showed the highest binding affinity for kappa receptor (K(i)=0.046 and 0.051 nM) and for mu receptor (K(i)=0.11 and 0.12 nM). Compound 1c showed the highest mu selectivity. The preliminary assay for agonist and antagonist properties of these ligands in stimulating [(35)S]GTPgammaS binding mediated by the kappa opioid receptor illustrated that all of these ligands were kappa agonists. At the mu receptor, compounds 1b, 1c, 2b, and 3b were agonists, while compounds 2c-e and 3c-e were mu agonists/antagonists.     

In vivo rat brain opioid receptor binding of LY255582 assessed with a novel method using LC/MS/MS and the administration of three tracers simultaneously

LY255582 is a pan opioid selective receptor antagonist that has been shown to have high affinity for mu, delta, and kappa receptors in vitro. In order to better understand the in vivo opioid receptor selectivity of LY255582, we developed in vivo receptor occupancy assays in the rat for the opioid mu, kappa and delta receptors using the occupancy tracers naltrexone, GR103545 and naltriben respectively. Individual assays for each target were established and then a "triple tracer" assay was created where all three tracers were injected simultaneously, taking advantage of LC/MS/MS technology to selectively monitor brain tracer levels. This is the first report of a technique to concurrently measure receptor specific occupancy at three opioid receptors in the same animal. The opioid subtype selective antagonists cyprodime, JDTic and naltrindole were used to validate selectivity of the assay. Examination of LY255582 in dose-occupancy experiments demonstrated a relative order of potency of mu>kappa>delta, reproducing the previously reported order determined with in vitro binding.