间硝苯地平对老龄肾性高血压大鼠心肌和脑微粒体Na+,K+-ATP酶,Ca2+-ATP酶和Mg2+-ATP酶活性的影响

间硝苯地平(m-Nif,ig20mg·kg^-1·d^-1持续给药9周)可显著降低老龄肾性高血压大鼠(RVHR)血压和左室重量(P<0.01),增高心、脑微粒体Na⁺,K⁺-ATP酶和Ca²⁺-ATP酶活性(P<0.01),降低Mg²⁺-ATP酶活性,体外量效关系研究发现,m-Nif在较高剂量(10～1000μmol·L^-1)时可增高RVHR心脑微粒体Na⁺,K⁺-ATP酶和Ca²⁺-ATP酶活性,且随剂量增加而增高。上述结果表明,m-Nif可改善老龄RVHR心脑微粒体Na⁺,K⁺泵和Ca²⁺泵功能。     

柴胡皂甙和甘草甜素抑制Na+,K+-ATP酶活性的构效关系

研究在离体条件下各种单体柴胡皂甙和甘草甜素抑制Na⁺,K⁺-ATP酶活性的构效关系。实验结果表明,各种柴胡皂甙抑制Na⁺,K⁺-ATP酶活性的作用强度依次为:b₁>d>b₂>b₄>a>b₃>e>c。柴胡皂甙化学结构中的C₂₃-OH,C₁₆-OH及C₁₁和C₁₃的共轭双烯可能对其抑制活性起重要作用。甘草甜素(GL),甘草次酸(GA)和生胃酮(18-β-甘草次酸半琥珀酸双钠盐,CX)抑制Na⁺,K⁺-ATP酶活性的作用强度依次为GA≥CX>GL。研究还证明,柴胡皂甙d对Na⁺,K⁺-ATP酶的抑制为非竟争性抑制。     

前胡香豆素对肾型高血压大鼠左室肥厚及心肌胞内钙、Na+,K+-ATP酶和Ca2+,Mg2+-ATP酶活性的影响

目的研究前胡香豆素组分对肾型高血压左室肥厚的预防和逆转作用及机制。方法用两肾一夹肾型高血压左室肥厚大鼠(RHR)模型,测定前胡香豆素组分对其血压、左室湿重、心肌细胞面积、胞内静息钙及胞膜和线粒体ATP酶活性的影响。结果前胡香豆素组分(30 mg·kg^-1·d^-1,ig)预防组及逆转组大鼠血压、左室湿重/体重均较肥厚组明显降低;左室心肌细胞面积、胞内静息钙均较肥厚组降低;对KCl致钙浓度升高亦明显低于肥厚组;两组均可增加心肌细胞膜及线粒体Na⁺,K⁺-ATP酶和Ca²⁺,Mg²⁺-ATP酶活性。结论前胡香豆素组分可预防及逆转RHR左室肥厚,减少心肌细胞内钙含量,增加ATP酶活性。     

人参二醇皂甙和三醇皂甙对兔纹状体ATP酶的影响

本文报道用体外给药法,观察了PDS和PTS对纹状体ATP酶(Na⁺、K⁺-ATP酶,Ca²⁺-ATP酶及M²⁺-ATP酶)的影响。结果发现PDS和PTS对Na⁺,K⁺-ATP酶都有明显的抑制作用,且随PDS和PTS浓度的高低,其抑制作用增强或减弱;对Ca²⁺-ATP酶,PDS在10^-5g/ml时有激活作用,当浓度增高到10^-3g/mL时则转为抑制,而PTS仅为抑制效应;对于Mg²⁺-ATP酶能被PDS所兴奋,而被PTS所抑制。此结果表明PDS和PTS对中枢神经系统的作用,可能与其影响脑内ATP酶有密切的内在联系。     

丙泊酚对大鼠脑突触体Na+, K+-ATP酶和Ca2+-ATP酶活性的影响

Effect of propofol on Na⁺, K⁺-ATPase and Ca²⁺-ATPase activities of cerebral synaptosomes was investigated in rats. It was found that propfol 50 mg·kg^-1 ip significantly inhibited Na⁺, K⁺-ATPase activity of hippocampal and brain stem′s synaptosomes (P<0.01). Propofol 100 mg·kg^-1 ip significantly reduced Na⁺, K⁺-ATPase and Ca²⁺-ATPase activity of cerebrocortical, brain stem′s and hippocampal synaptosomes (P<0.01). It is suggested that the central inhibitory effect of propofol may be related to the inhibition of Na⁺, K⁺-ATPase and Ca²⁺-ATPase activity of cerebral synaptosomes.     

羟苯氨酮强心作用的生化机理研究

目的：研究羟苯氨酮(oxyphenamone, Oxy)强心作用的生化机理。方法：采用Na⁺,K⁺-ATP酶活性和cAMP-PDE活性、肌浆网Ca²⁺-ATP酶活性和cAMP含量以及心肌肌原纤维Ca²⁺,Mg²⁺-ATP酶活性等测定法,研究Oxy对它们的影响,并与milrinone和MCI-154作比较。 结果：Oxy对Na⁺,K⁺-ATP酶和PDE无抑制作用,也不影响心肌cAMP含量,但能显著增强心肌肌原纤维对Ca²⁺的敏感性,高浓度时轻度抑制心肌肌浆网Ca²⁺-ATP酶活性。结论：Oxy的强心作用方式不同于强心苷、β受体激动剂和PDE抑制剂等强心药,可能为一种新的钙增敏性强心药物。     

中药大黄的生化学研究ⅩⅫ蒽醌衍生物对兔肾髓质Na+-K+-ATP酶活性的抑制和利尿作用

家兔实验表明:大黄素、大黄酸以30 mg/kg的剂量灌胃给药,2～4h后尿量、排Na⁺和K⁺量达最高峰,比对照组明显增多。而芦荟大黄素和大黄酚的作用较弱。大黄素、大黄酸和芦荟大黄素对免肾髓质Na⁺-K⁺-ATP酶活性有较强的竞争性抑制作用。     

粉防已碱对大鼠心肌微粒体ATPases的作用

体外在常规反应条件下,粉防已碱(Tet)对大鼠心肌微粒体Na⁺,K⁺-ATPase活性无明显影响,但浓度依赖性抑制Mg²⁺-ATPase(IC₅₀=179μmol/L).Tet 10和100μmol/L使哇巴因(Oua)抑制Na⁺,K⁺-ATPase的量效曲线平行右移.Tet 100μmol/L可显著提高低K⁺或高Ca²⁺浓度时的Na⁺,K⁺-ATPase活性,但未能明显增加低Na⁺浓度时该酶的活性.动力学分析提示Tet 100μmol/L增加Na⁺,K⁺-ATPase对ATP的亲和力,但不改变其最大反应速度。     

α-青心酮对损伤的脑线粒体Na+,K+-ATPase活性和脑细胞耗氧的作用

目的研究α-青心酮对抗坏血酸和硫酸亚铁诱导脑线粒体Na⁺，K⁺-ATPase活性和脑细胞耗氧的作用。方法采用无机磷法测定Na⁺，K⁺-ATPase活性,分光光度法检测脑线粒体膨胀和脂质过氧化物，氧电极法测定脑细胞耗氧量。结果在抗坏血酸和硫酸亚铁的作用下，鼠脑线粒体Na⁺，K⁺-ATPase活性降低，线粒体膨胀和脑细胞脂质过氧化物升高。α-青心酮抑制其抗坏血酸和硫酸亚铁诱导脑线粒体和细胞的损伤,增加Na⁺，K⁺-ATPase活性，降低脑线粒体膨胀和脑细胞脂质过氧化物生成。α-青心酮还具有减少ADP刺激的脑细胞耗氧的作用。结论α-青心酮通过清除自由基和抗氧化作用保护脑细胞结构和功能的完整。     

四氢巴马汀等单胺排空作用的比较

利血平(1.5mg/kg,ip)单独给药后24h能显著降低大鼠脑内NA(—60%)和DA(—75%)。预先给予dl-THP(60mg/kg)能使脑内NA和DA进一步下降,分别为正常对照组的15和5%,与单给利血平组有显著性差别。dl-THP同样亦能协同利血平排空5HT的作用。相反,预先给予丁苯那嗪(50mg/kg)则部分拮抗利血平的排空作用。此外,dl-THP与利血平不同,对Na⁺K⁺-ATP酶和Mg²⁺-ATP酶活性无显著影响。l-或d-THP在10^-4mol/L的较高浓度下能诱发豚鼠输精管节律性收缩,并不被多种受体阻断剂拮抗。在体研究表明,dl-THP在较大剂量下与利血平相似,降低犬鼠体温。     

Involvement of dopamine system in regulation of Na+,K+-ATPase in the striatum upon activation of opioid receptors by morphine

The striatum is believed to be a crucial brain region associated with drug reward. Adaptive alteration of neurochemistry in this area might be one potential mechanism underlying drug dependence. It has been proposed that the dysfunction of Na+,K+-ATPase function is involved in morphine tolerance and dependence. The present study, therefore, was undertaken to study the adaptation of the striatal Na+,K+-ATPase activity in response to morphine treatment. The results demonstrated that in vivo short-term morphine treatment stimulated Na+,K+-ATPase activity in a dose-dependent manner. This action could be significantly inhibited by D2-like dopamine receptor antagonist S(-)-3-chloro-5-ethyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxybenzamine (eticlopride). Contrary to shortterm morphine treatment, long-term morphine treatment significantly suppressed Na+,K+-ATPase activity. This effect could be significantly inhibited by D(1)-like dopamine receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH 23390). However, both short-term and long-term morphine treatment-induced changes in Na+,K+-ATPase activity could be reversed by opioid receptor antagonist naltrexone. It was further found that cAMP-dependent protein kinase (PKA) was crucially involved in regulating Na+,K+-ATPase activity by morphine. Different regulation of the phosphorylation levels of the alpha3 subunit of Na+,K+-ATPase by PKA was related to the distinct modulations of Na+,K+-ATPase by short-term and long-term morphine treatment. Short-term morphine treatment inhibited PKA activity and then decreased the phosphorylation of Na+,K+-ATPase, leading to increase in enzyme activity. These effects were sensitive to eticlopride or naltrexone. Conversely, long-term morphine treatment stimulated PKA activity and then increased the phosphorylation of Na+,K+-ATPase, leading to the reduction of enzyme activity. These effects were sensitive to SCH 23390 or naltrexone. These findings demonstrate that dopamine receptors are involved in regulation of Na+,K+-ATPase activity after activation of opioid receptors by morphine.     

Dopamine-glutamate interaction in rat striatal slices: changes of CCDPK II, PKA, and LDH activity by receptor-mediated mechanisms

AIM: To study the effects of dopamine (DA) and glutamate (Glu) and their receptor agonists/antagonists on Ca2+/calmodulin-dependent protein kinase II (CCDPK II), cyclic AMP-dependent protein kinase A (PKA) activities and the LDH release in rat striatal slices, and to examine the interaction between DA and Glu transmitter systems in striatum. METHODS: The activities of CCDPK II, PKA, and the release of LDH were determined with the 32P-incorporation and colorimetry respectively in rat striatal slices. RESULTS: (1) Exogenous DA, D1 receptor agonist SKF 38393 and D2 receptor agonist LY 171555 reduced CCDPK II activity in striatal slices; Glu also inhibited CCPPK II activity in a concentration-dependent manner. NMDA receptor antagonist MK-801 could antagonize the inhibitory effect of SKF 38393 and LY 171555 on the CCDPK II activity. D1 and D2 receptor antagonists SCH 23390 and spiperone could also antagonize the decrease of CCDPK II activity induced by Glu; (2) DA and SKF 38393 markedly increased PKA activity in striatal slices, which was reduced by MK-801; (3) DA and Glu increased the release of LDH from the striatal neurons in a concentration-dependent manner. MK-801 antagonized the increase of LDH induced by DA. Spiperone, rather than SCH 23390, could reduce the release of LDH from striatal neuron in the presence of Glu. CONCLUSION: The interaction between DA and Glu transmitter systems is found in the regulation of the CCDPK II and PKA activities and cell function in the striatum.     

Activation of dopamine D(1)-like receptor causes phosphorylation of alpha(1)-subunit of Na(+),K(+)-ATPase in rat renal proximal tubules

Dopamine causes inhibition of Na(+),K(+)-ATPase activity via activation of dopamine D(1)-like receptors. It is the phosphorylation of Serine(18) of the alpha(1)-subunit of Na(+),K(+)-ATPase which results in the inhibition of the enzyme activity; however, such a phosphorylation by dopamine D(1)-like receptor agonist has not been demonstrated in the proximal tubules. We show here by immunoprecipitation and detection with phosphoserine antibody that SKF 38393, a dopamine D(1)-like receptor agonist, causes phosphorylation of the alpha(1)-subunit of Na(+),K(+)-ATPase. The effect of (+/-)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride, SKF 38393, is blocked by R(+)-7-choro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-benzazepine hydrochloride, SCH 23390, a dopamine D(1)-like receptor antagonist, and staurosporin, a protein kinase C inhibitor. The phosphorylation is also increased by phorbol 12-13 dibutyrate ester. However, Rp-cAMP triethylamine, an inhibitor of protein kinase A, does not affect the SKF 38393-mediated phosphorylation of Na(+),K(+)-ATPase. Therefore, these results provide the evidence that dopamine D(1)-like receptor activation causes phosphorylation of the alpha(1)-subunit of Na(+),K(+)-ATPase in renal proximal tubules via protein kinase C pathway.     

左旋千金藤啶碱对外周血管多巴胺DA1和DA2受体亚型的作用

用家兔离体血管环方法,研究左旋千金藤啶碱(l-SPD)对外周血管DA₁和DA₂受体亚型的作用。结果表明,l-SPD使DA₁受体激动剂FODA诱发的肾、肺和肠动脉以及DA₂受体激动剂PBDA诱发的肠和股动脉舒张反应的量效曲线非平行右移,最大反应(Emax)降低,均呈非竞争性拮抗;l-SPD本身还可使肾和肺血管产生轻度的浓度依赖性舒张反应,表现为DA₁受体激动剂的作用特性。提示l-SPD为外周血管DA₁和DA₂受体的混合性阻滞剂并兼有DA₁受体部分激动剂的双重作用特性。     

Antagonistic actions of renal dopamine and 5-hydroxytryptamine: increase in Na+, K(+)-ATPase activity in renal proximal tubules via activation of 5-HT1A receptors.

1. 5-Hydroxytryptamine (5-HT) is antinatriuretic. Since this effect of 5-HT is not accomplished by changes in glomerular haemodynamics, we have examined in this study whether 5-HT may influence sodium excretion by affecting the Na+, K(+)-ATPase activity in renal cortical tubules. 2. Na+, K(+)-ATPase activity was determined as the rate of [32P]-ATP hydrolysis in renal cortical tubules in suspension. Basal Na+, K(+)-ATPase activity in renal tubules was 4.8 +/- 0.4 mumol Pi mg-1 protein h-1 (n = 8). The 5-HT1A receptor agonist, (+/-)-8-hydroxy-2-(di-n-propylamino) tetraline (8-OH-DPAT) (10 to 3000 nM) induced a concentration-dependent increase (P < 0.05) in Na+, K(+)-ATPase activity with an EC50 value of 355 nM (95% confidence limits: 178, 708). Maximal stimulation elicited by 3000 nM of 8-OH-DPAT was antagonized by the selective 5-HT1A receptor antagonist, (+)-WAY 100135 10 to 1000 nM) with an IC50 value of 20 nM (14, 29); 0.3 microM (+)-WAY 100135 completely abolished (P < 0.01) the stimulatory effect of 8-OH-DPAT. The stimulatory effect of 8-OH-DPAT was found to be time-dependent (15 +/- 2% and 66 +/- 7% increase at 2.5 and 5.0 min, respectively). The 5-HT2 receptor agonist alpha-methyl-5-HT (100 to 3000 nM) did not induce any significant changes in Na+, K(+)-ATPase activity (5.0 +/- 1.5 mumol Pi mg-1 protein h-1; n = 4). 3. The stimulatory effect 8-OH-DPAT was absent when homogenates were used. Stimulation occurred at a Vmax concentration (70 mM) of sodium supporting the notion that stimulation occurs independently of increasing sodium permeability. 4. The inhibitory effect of dopamine (P < 0.05) on Na+, K(+)-ATPase activity was blunted by co-incubation with 8-OH-DPAT (0.5 microM). 5. It is concluded that activation of 5-HT1A receptors increases Na+, K(+)-ATPase activity in renal cortical tubules; this effect may represent an important cellular mechanism, at the tubule level, responsible for the antinatriuretic effect of 5-HT.     

SCH 23390, a selective dopamine D1 antagonist, activates dopamine neurons but fails to prevent their inhibition by apomorphine

SCH 23390, a rather selective D1 receptor blocker, activates the firing rate of dopamine (DA) neurons in the substantia nigra (SN-DA neurons) in rats, similarly to haloperidol (a D1-D2 receptor antagonist) and sulpiride (a selective D2 receptor blocker). These neuroleptics produce no additional increase over the maximal activation produced by SCH 23390. Unlike haloperidol or sulpiride, SCH 23390 fails to prevent the inhibition by apomorphine of SN-DA neurons, a DA autoreceptor-mediated effect. It is suggested that the doses of SCH 23390 that stimulate DA neurons block D2 in addition to D1 receptors, or that D1 blockade results in the functional inactivation of a specific population of D2 receptors as well. The failure of SCH 23390 to block the apomorphine effect indicates that DA autoreceptors can be pharmacologically differentiated form postsynaptic DA receptors.     

Effects of locally applied D-1 and D-2 receptor agonists and antagonists studied with brain dialysis

The effect on dopamine (DA) release of D-1 and D-2 receptor agonists and antagonists applied locally in the caudate through a trans-striatal dialysis probe was studied in freely moving rats. D-2 agonists (LY 171555 and BHT 920) reduced DA release in a concentration-dependent manner. The same local application of haloperidol abolished the effect of 10 microM LY 171555 and BHT 920. A specific D-1 agonist, the catechol benzazepine SKF 38393, reduced DA release and this effect was not modified by systemic or local administration of the D-1 antagonist, SCH 23390, nor by the D-2 antagonist, haloperidol. In contrast, the non-catechol D-1 agonist, CY 208243, failed to modify DA release. Local application of the D-1 antagonist, SCH 23390, or of the D-2 antagonist, (-)-sulpiride, stimulated DA release in a concentration-dependent manner. The D-1 agonist, CY 20843, reversed the stimulatory effect of SCH 23390 but not that of (-)-sulpiride. It is concluded that D-1 and D-2 receptors located in the caudate control DA release separately in this area.     

Studies on the mechanism of action of the gastric H+,K(+)-ATPase inhibitor SPI-447

3-Amino-5-methyl-2(2-methyl-3-thienyl)- imidazo[1,2-a]thieno[3,2-c]pyridine, SPI-447, is a potent gastric H+,K(+)-ATPase inhibitor, but a detailed mechanism of the inhibition is unknown. This study was designed to investigate the mechanism by which SPI-447 inhibits gastric H+,K(+)-ATPase. For this purpose, the inhibitory action of SPI-447 on gastric H+,K(+)-ATPase from porcine gastric mucosa was compared with that of omeprazole (an irreversible inhibitor) and SCH28080 (a reversible inhibitor). All compounds produced dose-dependent inhibition of gastric H+,K(+)-ATPase, and the inhibitory intensities were increased under acidic conditions. The anti-H+,K(+)-ATPase actions of SPI-447 and SCH28080 were attenuated by dilution, but not influenced by glutathione pretreatment. In contrast, that of omeprazole was not influenced by dilution, but was suppressed by glutathione pretreatment. KCl addition reversed the inhibition of H+,K(+)-ATPase-mediated H(+)-transport by SPI-447 and SCH28080, but had no effect on that by omeprazole. The anti-gastric H+,K(+)-ATPase action of SPI-447 was additive with that of SCH28080. SPI-447 and SCH28080 had no effect on Na+,K(+)-ATPase activity. These findings indicated that the inhibitory mechanism of SPI-447 on gastric H+,K(+)-ATPase was similar to that of SCH28080, but different from that of omeprazole; i.e., 1) reversible, 2) SH-group independent, 3) K(+)-competitive, and 4) highly specific against gastric H+,K(+)-ATPase.     

Neurophysiological evidence that D-1 dopamine receptor blockade attenuates postsynaptic but not autoreceptor-mediated effects of dopamine agonists

The putatively selective D-1 dopamine receptor antagonist SCH 23390 was used to study the role of the D-1 dopamine receptor in mediating the pre- and postsynaptic effects of dopamine agonists in the basal ganglia. SCH 23390 (1 mg/kg) had no significant effect on the tonic activity of substantia nigra dopamine neurons in 47% of the 19 cells studied, while the firing rates of 53% of the cells were increased. SCH 23390 did not shift the dose response of these cells to apomorphine, whereas the selective D-2 antagonist, YM-09151-2 completely blocked apomorphine's inhibitory effects on nigral dopamine cell activity. These results suggest that SCH 23390 does not interact with the D-2 dopamine autoreceptors, but does excite a subpopulation of dopamine neurons presumably through postsynaptic actions. In contrast to its inability to modify the effects of apomorphine on dopamine autoreceptors, SCH 23390 partially to fully reversed the effects of apomorphine on globus pallidus and substantia nigra pars reticulata cell activity and significantly attenuated the effects of apomorphine, pergolide, quinpirole (LY 171555) and d-amphetamine on firing rates of globus pallidus neurons. The D-1 antagonist alone had no significant effect on tonic globus pallidus neuronal activity. SCH 23390 was more potent than haloperidol in its ability to attenuate the effects of apomorphine on pallidal activity, but unlike haloperidol, was unable to totally inhibit these effects, suggesting that the two antagonists block the excitatory effects of apomorphine on pallidal cell firing rates by different mechanisms. The serotonin2 receptor antagonist, ketanserin, had no effect on pallidal or dopamine cell activity, indicating that the effects of SCH 23390 were not mediated through interactions with serotonin2 receptors. These results suggest that D-1 receptor blockade attenuates the postsynaptic, but not autoreceptor-mediated effects of dopamine agonists.