Effect of morphine on the turnover and synthesis of (leu-3H)-protein and (ch-14C)-phosphatidylcholine in discrete regions of the rat brain

The effect of acute and chronic morphine treatment on the synthesis and turnover of ³H-leucine-labeled protein and ¹⁴C-choline-labeled phosphatidylcholine was measured in discrete regions of the rat brain. Chronic morphine treatment had the following effects on turnover. In the crude mitochondrial fraction of all brain regions studied, the turnover of ³H-protein was decreased. Microsomal ³H-protein turnover was increased in the cerebellum and hypothalamus and decreased in the cortex. The turnover of ¹⁴C-phosphatidylcholine was increased in the crude mitochondrial fraction of the brain stem, hypothalamus and diencephalon, but decreased in the cortex. In the microsomal fraction, the turnover of ¹⁴C-phosphatidylcholine was decreased in the cortex, brain stem and caudate nucleus, but increased in the diencephalon. Acute morphine treatment decreased ¹⁴C-phosphatidylcholine synthesis in the cortex (58 per cent) and cerebellum (49 per cent), but increased synthesis in the hypothalamus (95 per cent) and diencephalon (285 per cent). Acute morphine treatment decreased ³H-protein synthesis in the cortex (77 per cent) and diencephalon (73 per cent), but increased ³H-protein synthesis in the hypothalamus (55 per cent) and caudate nucleus (146 per cent). The relevance of these findings to current theories of narcotic tolerance and physical dependence development is discussed.     

Properties of the interaction between ketamine and opiate binding sites in vivo and in vitro

Analgesia induced by ketamine appears to be partially mediated by opiate mechanisms. Not only is its action attenuated by the narcotic antagonist naloxone, but the drug has a weak affinity for, and interacts stereoselectively at, opiate receptors. It also produces a classical narcotic action on the guinea-pig ileum. The present study showed that analgesic doses of the drug in rats yielded concentrations sufficient to interact effectively at opiate binding sites in vivo. A dose-dependent (80-120 mg/kg i.p.) inhibition of the binding of [3H]naloxone was observed in both brain and spinal cord. All regions of the brain (except the cerebellum) were affected, but the reduction was significant in the cortex, hippocampus, thalamus and striatum. Thus, a component of ketamine-induced analgesia could be related to a functional interaction with opiate receptors. Additionally, ketamine may be similar to morphine in its preference for the mu, rather than the delta sub-type of opiate receptors, and thus may promote mu-mediated pharmacological effects. For example, in vitro studies of radioligand binding showed that ketamine and morphine were four times more effective in inhibiting the binding of [3H]dihydromorphine than that of [3H] [D-Ala2, D-Leu5] enkephalin. On the other hand, ketamine also effectively interacted at a component of the sigma opiate/phencyclidine binding sites that appears to be relatively insensitive to morphine. This component may be involved in dysphoria induced by ketamine.     

Probes for narcotic receptor mediated phenomena. 13. Potential irreversible narcotic antagonist-based ligands derived from 6,14-endo-ethenotetrahydronororipavine with 7-(methoxyfumaroyl)amino, (bromoacetyl)amino, or isothiocyanate electrophiles: chemistry, biochemistry, and pharmacology

N-Allyl-, N-(cyclopropylmethyl)-, and N-propyl-endo-ethenotetrahydronororipavines (N-substituted 6,14-endo-etheno-4,5-epoxy-3-hydroxy-6-methoxymorphinans) were synthesized with potential acylating or alkylating moieties at the C-7 position (isothiocyanato, (bromoacetyl)amino, and (methoxyfumaroyl)amino) and examined in vivo for their narcotic agonist and antagonist activities and for their ability to interact with opioid receptors in vitro. The N-(cyclopropylmethyl)-substituted compounds were found to have the highest affinity for opioid receptors among these N-substituted compounds, although all of them were found to be reasonably potent narcotic antagonists in the mouse tail flick vs. morphine assay. Their in vivo potency ranged from 1/8 to 4 times that of nalorphine on intravenous injection in mice. Rat brain membrane binding studies indicated that the compounds interacted with opioid receptors with potencies that ranged from 0.5 times that of morphine (8c, 9c, and 10c) to 0.017 that of morphine (8b). Among the compounds studied here, only the previously reported isothiocyanato compound (10c) and (methoxyfumaroyl)amino compound (8c) interacted irreversibly and selectively with mu or delta opioid receptors, respectively, in assays using NG108-15 neuroblastoma-glioma hybrid cells and/or in a rat brain membrane preparation. Both 8c and 10c were found to interact irreversibly, to a limited extent, with kappa opioid sites in rat brain membranes in which the mu and delta opioid receptors were depleted by interaction with the mu-selective irreversible ligand BIT and the delta-selective irreversible ligand FIT. Neither compound showed irreversible actions in the electrically stimulated mouse vas deferens preparation.     

Antioxidant status in different regions of heroin addicts' brain

Heroin is an illicit narcotic abused by millions of people worldwide. In the present work, we estimated peroxyl radical-trapping capacity (PRTC), oxidative stress markers - malondialdehyde and protein carbonyl groups, as well as antioxidant enzymes - superoxide dismutase and catalase, in different regions of brain. Studies conducted on nine brains from heroin abusers and eight from control subjects revealed a decrease in PRTC in each part of heroin intoxicated brains and an increase in lipid peroxidation in brain cortex, brain stem and white matter but not in hippocampus. Protein oxidation was increased in hippocampus and in brain stem, but it was unchanged in gray and white matters. Superoxide dismutase and catalase activities were unchanged in heroin addicts. We conclude that heroin intoxication changes the antioxidant status in human brain by increasing the amount of organic rather then inorganic peroxides. The most severe condition of oxidative stress occur in brain stem.     

Stimulation of mitogen-activated protein kinase kinases (MEK1/2) by mu-, delta- and kappa-opioid receptor agonists in the rat brain: regulation by chronic morphine and opioid withdrawal

Opioid addiction modulates the extracellular signal-regulated kinase (ERK) leading to synaptic plasticity in the brain. ERK1/2 are stimulated by mitogen-activated protein kinase kinases (MEK1/2), but little is known about the regulation of MEK activity by opioid drugs. This study was designed to assess the acute effects of selective mu-, delta-, and kappa-opioid receptor agonists, as well as those induced by chronic morphine and opioid withdrawal, on the content of phosphorylated MEK1/2 in the rat brain. Sufentanil (1-30 microg/kg, 30-120 min) induced dose- and time-dependent increases in MEK1/2 phosphorylation in the cerebral cortex and corpus striatum (30-177%) through a naloxone-sensitive mechanism. Morphine (100 mg/kg, 2 h) also augmented MEK1/2 phosphorylation in the both brain regions (50-70%). Similarly, the selective delta-opioid receptor agonist SNC-80 (10 mg/kg, 30 min) increased MEK1/2 activity in the cortex (60%) that was antagonized by naltrindole. In contrast, the selective kappa-opioid receptor agonist (-)-U50488H (10 mg/kg, 30-120 min) did not modify significantly MEK1/2 phosphorylation in the cortex. Chronic morphine (10-100 mg/kg, 5 days) was not associated with alterations in the content of phosphorylated MEK1/2 in the brain (induction of tachyphylaxis to the acute effects). In morphine-dependent rats, however, naloxone (2 mg/kg)-precipitated withdrawal (2-6 h) induced robust increases in MEK1/2 phosphorylation in cortex (27-49%) and striatum (83-123%). Spontaneous opioid withdrawal (24 h) in morphine-dependent rats did not alter MEK1/2 activity in the brain. The findings may be relevant in the context of the pivotal role played by the MEK/ERK pathway in various long-lasting forms of synaptic plasticity associated with opioid addiction.     

吗啡依赖小鼠脑组织cGMP水平、鸟苷酸环化酶及磷酸二酯酶活性的调节

以递增剂量吗啡sc,使小鼠产生对吗啡的躯体依赖,观察脑组织cGMP水平、PDE和sGC的活性变化及PKA对其磷酸化调节。结果表明,(1)小脑、纹状体、海马及大脑皮质cGMP含量显著降低;(2)在小脑、海马中sGC活性明显降低,PDE活性无明显变化,在纹状体及大脑皮质中均明显升高,且体外磷酸化水平也均明显下降,PKA抑制剂可抑制此变化;(3)纳洛酮拮抗组未见上述变化。结果提示,吗啡依赖小鼠脑组织cGMP水平普遍降低,在小脑和海马可能因sGC活性下降引起,在纹状体及大脑皮质可能因PDE活性升高所致。     

Opiate-receptor mediated changes in monoamine synthesis in rat brain

The effects of morphine, β-endorphin, naloxone and naltrexone on the rate of tyrosine and tryptophan hydroxylation were investigated in vivo by measuring the accumulation of dopa and 5-hydroxytryptophan (5-HTP) in different brain regions of rats after inhibition of the aromatic L-amino acid decarboxylase. The cerebral concentrations of tyrosine and tryptophan were also measured. Morphine (3–30 mg kg^?1) increased the accumulation of dopa dose-dependently (25–50%) in the dopamine-rich areas (limbic forebrain and corpus striatum). In the noradrenaline-predominant parts of the brain (containing hemispheres, diencephalon and lower brain stem) only the highest dose of morphine (30 mg kg^?1) significantly increased dopa formation (47%). Similarly to morphine, intracerebroventricularly injected β-endorphin (5–10 βg per rat) increased the formation of dopa. This increase was doubled in limbic forebrain, corpus striatum and cerebral hemispheres. Doses of 10 to 20 μg of β-endorphin were needed to increase dopa accumulation in the diencephalon and the lower brain stem. Naloxone antagonized the β-endorphin-induced increases in dopa. But naloxone and naltrexone (10–100 mg kg^?1) decreased the dopa formation in the dopamine-rich areas (about 20–25 %) but not in the noradrenaline-predominant areas. Morphine (30 mg kg^?1) and β-endorphin (5 μg per rat) increased the accumulation of 5-HTP whereas naloxone and naltrexone (10 mg kg^?1) tended to decrease its formation. Morphine and β-endorphine increased the concentrations of tyrosine and tryptophan, and naloxone decreased the cerebral tryptophan concentration. These results show that the effects of a narcotic agonist (morphine) and of pure narcotic antagonists (naloxone and naltrexone) on the synthesis of dopamine and 5-HT are opposite to each other. Furthermore, the effects of β-endorphine on brain monoamine synthesis are remarkably similar to those of morphine. Thus, it is probable that opiate receptors and their endogenous ligands are involved in the regulation of dopamine and 5-HT synthesis.     

Chronic morphine induces up-regulation of the pro-apoptotic Fas receptor and down-regulation of the anti-apoptotic Bcl-2 oncoprotein in rat brain.

1. This study was designed to assess the influence of activation and blockade of the endogenous opioid system in the brain on two key proteins involved in the regulation of programmed cell death: the pro-apoptotic Fas receptor and the anti-apoptotic Bcl-2 oncoprotein. 2. The acute treatment of rats with the mu-opioid receptor agonist morphine (3-30 mg x kg(-1), i.p., 2 h) did not modify the immunodensity of Fas or Bcl-2 proteins in the cerebral cortex. Similarly, the acute treatment with low and high doses of the antagonist naloxone (1 and 100 mg x kg(-1), i.p., 2 h) did not alter Fas or Bcl-2 protein expression in brain cortex. These results discounted a tonic regulation through opioid receptors on Fas and Bcl-2 proteins in rat brain. 3. Chronic morphine (10-100 mg x kg(-1), 5 days, and 10 mg x kg(-1), 13 days) induced marked increases (47-123%) in the immunodensity of Fas receptor in the cerebral cortex. In contrast, chronic morphine (5 and 13 days) decreased the immunodensity of Bcl-2 protein (15-30%) in brain cortex. Chronic naloxone (10 mg x kg(-1), 13 days) did not alter the immunodensities of Fas and Bcl-2 proteins in the cerebral cortex. 4. The concurrent chronic treatment (13 days) of naloxone (10 mg x kg(-1)) and morphine (10 mg x kg(-1)) completely prevented the morphine-induced increase in Fas receptor and decrease in Bcl-2 protein immunoreactivities in the cerebral cortex. 5. The results indicate that morphine, through the sustained activation of opioid receptors, can promote abnormal programmed cell death by enhancing the expression of pro-apoptotic Fas receptor protein and damping the expression of anti-apoptotic Bcl-2 oncoprotein.     

Morphine tolerance and dependence in noradrenaline neurones of the rat cerebral cortex

Summary By subcutaneous implantation of 2 or 13 morphine pellets (75 mg morphine/pellet), rats were made tolerant to, and dependent on narcotic analgesics. Occipital cortex slices from dependent animals and placebo-implanted controls were incubated with (-)-³H-noradrenaline and subsequently superfused with physiological salt solution. The accumulation of ³H-noradrenaline was not changed by pretreatment with 2, but was slightly decreased by pretreatment with 13 morphine pellets. The overflow of tritium evoked by electrical field stimulation was higher in slices from morphine-implanted rats than in those from placebo controls. Morphine and levorphanol, added in vitro, inhibited the stimulation-induced overflow of tritium at, similar concentrations and to a similar degree in slices from morphine-and placebo-pretreated animals. —It is concluded that, during chronic treatment with morphine, an adaptation takes place in the brain to compensate for the acute effect of narcotic analgesics, i.e. inhibition of the release of noradrenaline by nerve impulses. The chain of events from the drug-receptor interaction to the depression of the release process can be excluded as substrate of this adaptation. During with-drawal, the compensatory changes provoke an enhanced increase of extracellular noradrenaline during nerve impulses.     

Effects of morphine, in vitro and in vivo, on thyrosine hydroxylase activity in rat brain

The effect of morphine on the synthesis of catecholamines was determined in rat brain. In agreement with other studies, morphine produced a dose-dependent increase in the biosynthesis of the catecholamines. To assess whether morphine might enhance the synthesis of norepinephrine and dopamine by a direct chemical interaction with tyrosine hydroxylase, the rate-limiting step in their biosynthesis, the effects of the narcotic on the activity of the enzyme were determined in several regions of rat brain. Morphine, in vitro, from 10^?8 to 10^?2 M had no effect on the activity of tyrosine hydroxylase in any region examined. Moreover, morphine (10^?5 and 10^?3 M) had no effect on the apparent K_m of tyrosine hydroxylase for either substrate or cofactor (6-7-dimethyl-5, 6,7,8-tetrahydropterine). In addition, morphine (10^?5 and 10^?3 M) failed to block the inhibition of tyrosine hydroxylase, in vitro, by norepinephrine and dopamine in the hypothalamus and caudate respectively. The effects of morphine treatment, in vivo, on enzyme activity were also examined. The results of these studies indicated that acute injections of morphine had no effect on tyrosine hydroxylase activity, in vitro, indicating that the drug did not alter the level of an endogenous activator or inhibitor of tyrosine hydroxylase. Further studies indicated that development of tolerance to and physical dependence on morphine was not associated with an increase in the activity of brain tyrosine hydroxylase activity. The results of these studies suggest that morphine does not enhance the biosynthesis of catecholamines by a direct effect of tyrosine hydroxylase and that tolerance to the narcotic is not characterized by an induction of this enzyme.     

Effects of acute morphine administration on noradrenaline turnover and metabolism in various brain parts of control and handled rats

The main purpose of these experiments was to study whether the morphine-induced changes in cerebral noradrenaline (NA) turnover differ between various brain areas of male Wistar rats assessed by the alpha-methyl-p-tyrosine (alpha MT)-induced NA depletion. The effects of repeated saline injections (20 days) on the morphine-induced changes in NA and also in free and sulphated 3-methoxy-4-hydroxyphenylethylene glycol (MOPEG) concentrations were studied. 5 to 40 mg/kg of morphine reduced the alpha MT-induced NA depletion in the cortical hemispheres, while 40 mg/kg of morphine enhanced it in the lower brain stem. 10 mg/kg of morphine lowered the NA concentration in limbic forebrain and hypothalamus and increased it in the cortical areas. It also elevated the MOPEG concentrations in all brain parts with the sole exception of sulphated MOPEG in the cortical hemispheres. Naltrexone antagonized the morphine-induced changes in NA turnover and MOPEG concentrations. The only significant handling-induced change was the elevation of NA concentrations in the hypothalamus. The increasing effect of morphine on the sulphated MOPEG concentration in the prefrontal cortex and the lower brain stem was attenuated in handled rats. In conclusion, these findings show that, the response of cortical NA neurones to acute morphine administration is retardation of turnover rather than activation which occurs most notably in the lower brain stem. Furthermore, the responses are modified by previous exposure of rats to handling.     

Comparison of (-)-eseroline with (+)-eseroline and dihydroseco analogues in antinociceptive assays: confirmation of rubreserine structure by X-ray analysis

The enantiomers of eseroline bind to opiate receptors of rat brain membranes with equal affinities and show opiate agonist properties as inhibitors of adenylate cyclase in vitro. However, only (-)-eseroline shows potent narcotic agonist activity in vivo, similar to that of morphine. Neither (-)-noreseroline, (+)-eseroline, nor the open dihydroseco analogue (-)-8 shows analgetic effects in vivo. The structure of rubreserine being a resonance hybrid of an o-quinone with its zwitterionic mesomer is confirmed by solid-state X-ray diffraction analysis.     

毒蕈碱和NMDA受体拮抗剂对吗啡依赖大鼠脊髓和脑干前脑啡肽原和前强啡肽原mRNA表达的影响

目的　观察毒蕈碱 (M)受体拮抗剂对吗啡依赖大鼠脊髓和脑干前脑啡肽原 ( preproenkephalin ,PPE)和前强啡肽原 ( preprodynorphin ,PPD)mRNA表达的影响。 方法　本文利用逆转录聚合酶链反应 (RT PCR) ,以 β actinmRNA为内标检测了PPE和PPDmRNA。结果　吗啡依赖大鼠脊髓和脑干PPE基因表达和正常大鼠相比都略有增加 ,吗啡依赖大鼠注射纳洛酮激发戒断反应后 ,脊髓PPE基因表达增加 ,而脑干中变化不明显。吗啡依赖大鼠脊髓和脑干PPD基因表达都低于正常大鼠组 ,吗啡戒断反应时脊髓PPD基因表达在 1h变化不明显 ,2h时增加到峰值 ,4h时仍高于依赖组 ,而脑干强啡肽基因表达在 1h、2h和 4h时都明显减少。经M受体拮抗剂甲基东莨菪碱和M1拮抗剂 pirenzepine处理后大鼠脊髓和脑干PPE和PPD基因表达较戒断 1h组有不同程度的增加 ;经NMDA受体拮抗剂MK 80 1处理后 ,脊髓和脑干中PPE基因较戒断组 1h无明显差异 ,脊髓和脑干PPD基因表达较戒断组明显增加 ;而经NOS抑制剂L N 硝基精氨酸甲酯 (L NAME)处理后大鼠脊髓和脑干PPE基因表达较戒断 1h组有不同程度的增加 ,脊髓和脑干PPD基因表达变化不明显。脊髓和脑干中 β actin基因表达在各处理组之间没有差别。结论　M受体拮抗剂、NMDA受体拮抗剂和NOS抑制剂在吗啡戒断反应时增加     

Increase in rat regional brain cyclic nucleotides by thyrotropin-releasing hormone (TRH) and its analog DN-1417

The effects of thyrotropin-releasing hormone (TRH) and its analog gamma-butyrolactone-gamma-carbonyl-L-histidyl-L-prolinamide citrate (DN-1417) on adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP) levels in rat brain were investigated using a radioimmunoassay method. The time course of elevation of these nucleotides in various brain regions after administration of DN-1417 showed a peak at 5 to 15 min followed by a gradual decrease. DN-1417 (1 to 10 mg/kg i.p.) caused a dose-related increase in cyclic AMP levels in the cerebellum, cerebral cortex, striatum, nucleus accumbens, thalamus, hypothalamus and brain stem; whereas significant increases in cyclic GMP were observed in the cerebellum, nucleus accumbens and brain stem. TRH (3 to 10 mg/kg i.p.) caused significant increases of cyclic AMP in the cerebellum, cerebral cortex, nucleus accumbens, thalamus and brain stem and also caused an increase in cerebellar cyclic GMP. With one exception, DN-1417, apomorphine (Apo), methamphetamine (MAP) (all, 3 mg/kg i.p.)- and TRH (10 mg/kg i.p.)-induced increases in cyclic nucleotides were blocked by pimozide (1 mg/kg i.p., 4 hr before), a dopamine receptor blocker; the exception was a TRH-induced increase in cerebellar cyclic GMP. These increases were not blocked by propranolol (10 mg/kg i.p., 30 min before), an adrenergic beta-receptor blocker. alpha-Methyl-p-tyrosine (alpha-MT, 250 mg/kg i.p., 4 hr before), a tyrosine hydroxylase inhibitor, almost completely blocked DN-1417- and MAP-induced increases in cyclic nucleotides, slightly blocked TRH-effects, and had no effect on Apo-effects. These in vivo results were confirmed in an in vitro system using brain slices. The addition of DN-1417 (10(-4) M) or TRH (10(-3) M) significantly enhanced the spontaneous [3H]-dopamine and [3H]-norepinephrine release from the superfused slices of the rat nucleus accumbens and cerebral cortex in vitro. The addition of DN-1417 (10(-4) M) or TRH (10(-4) M) had no effect on the activities of adenylate cyclase and guanylate cyclase, although only a high concentration (10(-3) M) of DN-1417 inhibited the cyclic AMP- and cyclic GMP-hydrolytic activities in various brain region homogenates. These results suggest that DN-1417 does not produce an increase in the levels of cyclic nucleotides by direct receptor-enzyme activation, but that DN-1417 like MAP causes the increase through endogenous catecholaminergic, particularly dopaminergic activation.     

Morphine-induced changes in cyclic AMP metabolism and protein kinase activity in the brain.

The effects of consecutive oral administration of morphine on the cyclic AMP synthesizing system and cyclic AMP dependent protein kinase activity in the cerebral cortex of mice were examined. The administration of morphine (2--4 weeks) induced an increase of the cyclic AMP formation by activating adenylate cyclase, whereas responses of the cyclic AMP synthesizing system to biogenic amines (norepinephrine, dopamine and histamine) added in vitro was found to be significantly attenuated in these animals. Cyclic AMP dependent protein kinase activity in the cerebral cortex was also increased following a consecutive oral administration of morphine. These changes in the activities of adenylate cyclase and protein kinase were found mainly in crude mitochondrial and/or synaptosomal fractions. Morphine induced decrease in the response of the cyclic AMP synthesizing system to biogenic amines was rapidly reversed, and a significant increase of the cyclic AMP formation in the presence of added norepinephrine compared with that found in morphinized animals was observed following the administration of levallorphan, a narcotic antagonist. On the other hand, the changes in adenylate cyclase and cyclic AMP dependent protein kinase activities were not affected significantly by levallorphan administration. These results suggest that alterations in activities of cyclic AMP synthesizing system and of cyclic AMP dependent protein kinase may be involved in processes of the formation of morphine dependence. Possible involvement of abrupt increments in the sensitivity of "norepinephrine receptor-adenylate cyclase" system and a subsequent increase in cerebral cyclic AMP is also suggested as a cause of morphine withdrawal syndrome.     

Synthesis and structure-activity relationships of 1-substituted 4-(1,2-diphenylethyl)piperazine derivatives having narcotic agonist and antagonist activity

Racemates and enantiomers of 1-substituted 4-[2-(3-hydroxyphenyl)-1-phenylethyl]piperazine derivatives (3-18) were synthesized, and their analgesic and other pharmacological activities and structure-activity relationships were investigated. The S-(+) enantiomers of 2a, 5, 7, 9, 10, and 15-18 had a stronger analgesic activity than their R-(-) enantiomers; analgesic activity of the strongest one [(S)-(+)-10] was 105 times as potent as that of morphine. The S-(+) enantiomers of these compounds had the opposite configuration to that of morphine with respect to its (C-9) asymmetric center but the same configuration to that of the tyrosine residue of Met5-enkephalin. The R-(-) enantiomers of 16 and 18 showed narcotic antagonist activity, but the S-(+) enantiomers did not. (R)-(-)-18 had analgesic and narcotic antagonist activities comparable to pentazocine but showed no significant physical dependence liability. From these results, it is suggested that these compounds show an uncommon enantioselectivity in comparison with morphine and its surrogates, and belong to a new series of compounds having a potent analgesic activity.     

2012-2014年天津市第三中心医院肿瘤科住院患者麻醉药品的使用情况分析

目的 调查天津市第三中心医院2012-2014年肿瘤科住院患者麻醉药品的使用情况和用药趋势,为临床合理应用及规范化管理麻醉药品提供参考.方法 统计肿瘤科住院患者麻醉药品的使用数据,对2012-2014年麻醉药品品种、用药处方数、各剂型使用量、用药频度(DDDs)等数据进行统计分析.结果 2012-2014年肿瘤科麻醉药品处方共计6860张,品规有10种,包括口服剂型6种,注射剂型3种,外用贴剂1种.麻醉药品用量呈逐年上升趋势,2014年用药频度(DDDs)排序前3位分别为吗啡缓释片(30 mg)、吗啡缓释片(10 mg)和盐酸羟考酮缓释片(10 mg);吗啡各年度用量有逐渐上升趋势,主要用于癌性疼痛患者.结论 天津市第三中心医院肿瘤科麻醉药品的使用情况基本合理,基本符合"癌症三阶梯止痛指导原则".     

Acceleration of cerebral noradrenaline turnover after morphine withdrawal and its retardation by acute morphine administration in rats

Summary To clarify the effects of withdrawal from chronic morphine treatment on cerebral noradrenaline (NA) turnover, we have measured the -methyl-p-tyrosine (MT)-induced depletion of NA in five brain areas of male Wistar rats given morphine twice daily for 40 or 60 days. After the last morphine dose (50 or 70 mg/kg) the rats were withdrawn for 1, 2 or 4 days. In order to study the development of tolerance a challenge dose of 10 mg/kg of morphine was given to some of the rats.Withdrawal of morphine accelerated the MT-induced NA depletion clearly in the hemispheres and the lower brain stem and slightly in the diencephalon. The acceleration was more pronounced in the brains of rats treated for 60 days than of those treated for 40 days. In the hemispheres the acceleration of NA depletion occurred at 1 and 2 days, in the diencephalon at 2 days, and in the lower brain stem at 2 and 4 days after morphine withdrawal. The most pronounced acceleration of NA depletion coincided with the maximum withdrawal-induced weight loss. The challenge dose of morphine clearly retarded the MT-induced NA depletion in the hemispheres of control rats treated chronically with saline. This retardation was even more pronounced in rats withdrawn from chronic morphine treatment for 1 or 2 days. The challenge dose slightly accelerated the MT-induced NA depletion in the lower brain stem of control rats. However, in rats withdrawn from chronic morphine treatment for 1 or 2 days the challenge dose instead of accelerating, clearly retarded, the NA depletion in the lower brain stem.Our results show that cerebral NA turnover is accelerated in rats withdrawn from morphine. The degree of this acceleration is proportional to the duration of chronic treatment. Tolerance does not seem to develop towards the NA release-inhibiting effect of morphine in the hemispheres, but develops towards the NA release-accelerating effect of morphine in the lower brain stem.     

Phosphorylation of Galphas influences its association with the micro-opioid receptor and is modulated by long-term morphine exposure

The recent biochemical demonstration of the association of the mu-opioid receptor (MOR) with Galpha(s) that increases after long-term morphine treatment (Mol Brain Res 135:217-224, 2005) provides a new imperative for studying MOR-Galpha(s) interactions and the mechanisms that modulate it. A persisting challenge is to elucidate those neurochemical parameters modulated by long-term morphine treatment that facilitate MOR-Galpha(s) association. This study demonstrates that 1) Galpha(s) exists as a phosphoprotein, 2) the stoichiometry of Galpha(s) phosphorylation decreases after long-term morphine treatment, and 3) in vitro dephosphorylation of Galpha(s) increases its association with MOR. Furthermore, our data suggest that increased association of Galpha(s) with protein phosphatase 2A is functionally linked to the long-term morphine treatment-induced reduction in Galpha(s) phosphorylation. These findings are observed in MOR-Chinese hamster ovary and F11 cells as well as spinal cord, indicating that they are not idiosyncratic to the particular cell line used or a "culture" phenomenon and generalize to complex neural tissue. Taken together, these results indicate that the phosphorylation state of Galpha(s) is a critical determinant of its interaction with MOR. Long-term morphine treatment decreases Galpha(s) phosphorylation, which is a key mechanism underlying the previously demonstrated increased association of MOR and Galpha(s) in opioid tolerant tissue.     

Actions of narcotics on brain dopamine metabolism and their relevance for "psychomotor" effects.

A review is given about the effects of narcotic analgesics, particularly of morphine, on the dopamine metabolism in the corpus striatum and about the relations of these effects to motility and "psychomotor" phenomena. In rats, acute doses of morphine decrease the dopaminergic neurotransmission in brain, without blocking postsynaptic dopamine receptors. Chronic treatment of rats with morphine reverses these acute effects of morphine and induces symptoms of an increased dopaminergic neurotransmission in brain. In mice and cats on the other hand, acute doses of morphine apparently increase dopaminergic neurotransmission. The effects of morphine on striatal dopamine metabolism seem to be a model well suited to study opioid-specific effects on a cellular level. Furthermore, they might also be responsible for some narcotic-specific effects on behaviour observed in animals and man.