归元片对小鼠吗啡行为敏化的影响

目的 :探讨中药复方制剂归元片对吗啡行为敏化的影响。方法 :测定小鼠的自主活动 ,观察归元片对小鼠自主活动的影响。给小鼠慢性吗啡处理 ,建立吗啡诱导的行为敏化小鼠模型 ,观察归元片对吗啡行为敏化的影响。结果 :(1)归元片 (2 5 - 10g·kg- 1 )明显抑制小鼠的自主活动 ,并呈剂量依赖性 ;(2 )归元片剂量依赖性地阻断小鼠吗啡行为敏化的获得和表达 ,但对行为敏化的转换无影响。结论 :归元片对中枢神经系统具有抑制作用 ,可以阻止吗啡成瘾行为的形成 ,对吗啡诱导的敏化行为具有抑制作用。提示归元片对吗啡的精神依赖性可能具有干预作用     

Y-IP5对小鼠吗啡行为敏化和条件性位置偏爱的影响

目的探讨新型化合物Y-IP5对吗啡诱导小鼠行为敏化和条件性位置偏爱(conditioned place preference,CPP)的影响。方法测定小鼠的自发活动,观察Y-IP5对小鼠自发活动及急性给予吗啡所诱导小鼠高活动性的影响;慢性吗啡处理小鼠,建立小鼠吗啡行为敏化和CPP模型,观察Y-IP5对行为敏化形成、转化、表达及CPP形成的影响。结果单次或多次给予Y-IP5都不影响小鼠的自发活动,但能抑制急性给予吗啡所致的小鼠高活动性(P<0.05);Y-IP5本身不诱导小鼠形成行为敏化和CPP,但能抑制吗啡诱导小鼠形成行为敏化和CPP(P<0.05),但Y-IP5对吗啡诱导小鼠行为敏化的转化和表达无抑制作用。结论Y-IP5对阿片类药物的精神依赖可能具有干预作用。     

5-羟色胺酸对吗啡诱导小鼠行为敏化的影响

研究中枢5-羟色胺能系统对吗啡诱导小鼠行为敏化的介导作用。选用雄性昆明小鼠，每天2次注射生理盐水或吗啡10mg／kg，连续3天。停药5天后，于第9天，进行吗啡激发试验，测定小鼠的自主活动60min，观察行为敏化效应。此外，选用5-羟色胺前体物质5-羟色氨酸作为工具药，分别在吗啡处理阶段（形成期），吗啡停药阶段（转换期）以及吗啡激发试验前腹腔注射20-80mg／kg5-羟色氨酸。激发试验给予吗啡后，立即测定小鼠的自主活动。实验第9天激发试验数据表明，每天2次反复给予吗啡的小鼠，其自主活动明显高于生理盐水对照组，说明小鼠对吗啡产生了行为敏化效应。5-羟色氨酸可以选择性抑制吗啡对小鼠行为敏化的诱导作用，其抑制作用呈剂量依赖性。然而，5-羟色氨酸对小鼠吗啡行为敏化的转换和表达无明显药理作用。因此，中枢5-羟色胺能系统的功能水平上调可能对吗啡诱导小鼠行为敏化效应具有一定的抑制作用。     

地高辛对小鼠吗啡行为敏化的影响

目的:探讨地高辛对小鼠吗啡行为敏化的影响.方法:测定小鼠的自主活动,观察地高辛对小鼠自主活动的影响.急性吗啡(10 mg·kg-1,ip)处理小鼠前给予地高辛,观察地高辛对急性吗啡引起小鼠高活动性的影响.慢性吗啡处理小鼠,建立吗啡行为敏化模型,观察地高辛对吗啡行为敏化的影响.结果:(1)地高辛(0.5 mg·kg-1-...     

槟榔碱对小鼠吗啡行为敏化的影响

目的:探讨槟榔嚼块的主要成分—槟榔碱,对小鼠吗啡行为敏化过程的影响。方法:测定小鼠的自主活动,观察ip槟榔碱对小鼠的自主活动及单次给予吗啡所诱导的小鼠高活动性的影响;建立吗啡诱导的小鼠行为敏化模型,观察槟榔碱对行为敏化形成、表达的影响。结果:(1)单次ip槟榔碱(0·25-2·0mg·kg-1)可剂量依赖性地抑制小鼠的自主活动(P<0·05),多次给药后这种抑制作用既不产生耐受,也不形成敏化;(2)槟榔碱(2·0mg·kg-1)可增强单次给予吗啡所诱导的小鼠的高活动性(P<0·05);(3)槟榔碱(2·0mg·kg-1)可增强吗啡诱导小鼠行为敏化的形成(P<0·05);(4)虽然槟榔碱(2·0mg·kg-1)多次给药降低吗啡诱导小鼠行为敏化表达的程度(P<0·05),但是槟榔碱(0·5-2·0mg·kg-1)单次给药不影响吗啡诱导小鼠行为敏化的表达。结论:槟榔嚼块中的主要成分槟榔碱能增强小鼠吗啡诱导的急性高活动性和吗啡行为敏化的形成,提示槟榔嚼块有可能增强吗啡的成瘾性。     

钩藤生物碱对小鼠苯丙胺行为敏化的影响

目的:探讨钩藤生物碱对苯丙胺行为敏化的影响。方法:测定小鼠的自主活动,观察钩藤及钩藤总碱对小鼠自主活动的影响。分别采用单次给予苯丙胺致小鼠高活动性及反复间断苯丙胺处理建立苯丙胺行为敏化小鼠模型,观察钩藤生物碱对苯丙胺高活动性及行为敏化获得和表达的影响。结果:钩藤碱低(40 mg.kg-1)、高(80 mg.kg-1)剂量和钩藤总碱(80 mg.kg-1)灌胃给药后,均能减少小鼠的自主活动,降低苯丙胺的高活动性,抑制小鼠苯丙胺行为敏化的获得,阻断小鼠苯丙胺行为敏化的表达,其中高剂量钩藤碱和钩藤总碱的作用较显著。结论:钩藤生物碱对中枢神经系统功能具有抑制作用,对苯丙胺诱导的小鼠行为敏化的获得和表达有抑制作用。提示钩藤生物碱对苯丙胺类物质的精神依赖具有干预作用.     

噻诺啡灌胃对小鼠吗啡行为敏化的影响

目的研究ig噻诺啡对小鼠吗啡行为敏化的影响。方法测定小鼠的自主活动，观察ig噻诺啡对小鼠自主活动及急性给予吗啡所诱导小鼠活动增强效应的影响；建立小鼠吗啡行为敏化模型，观察ig噻诺啡对行为敏化形成、转化及表达的影响。结果单次ig噻诺啡(1.25-5.0 mg·kg^-1)可剂量依赖性地降低小鼠的自主活动(P<0.01)，但多次给药可产生耐受。噻诺啡可有效地抑制急性给予吗啡所诱导的小鼠高活动性(P<0.05)及小鼠吗啡行为敏化的形成、转化和表达(P<0.05或P<0.01)。结论噻诺啡可抑制小鼠中枢神经系统，对阿片类药物的滥用和成瘾可能具有干预作用。     

归元片对小鼠甲基苯丙胺行为敏化的影响

目的:探讨中药复方制剂归元片对甲基苯丙胺行为敏化的影响.方法:测定小鼠的自主活动,观察归元片对小鼠自主活动及甲基苯丙胺急性活动增强效应的影响.小鼠慢性甲基苯丙胺处理,建立甲基苯丙胺诱导的行为敏化小鼠模型,观察归元片对甲基苯丙胺行为敏化获得和表达的影响.结果:归元片呈剂量依赖性降低小鼠的活动性,对甲基苯丙胺的急性高活动效应有抑制作用.归元片阻断小鼠甲基苯丙胺行为敏化的获得和表达.结论:归元片对中枢神经系统功能具有抑制作用,能抑制甲基苯丙胺行为敏化的获得和表达,提示归元片能抑制甲基苯丙胺的奖赏效应,可能对防治甲基苯丙胺的滥用和成瘾有效.     

噻诺啡对小鼠甲基苯丙胺行为敏化的影响

目的:探讨新型阿片受体部分激动剂-噻诺啡对小鼠甲基苯丙胺行为敏化过程的影响。方法:测定小鼠的自主活动,观察噻诺啡对小鼠的自主活动及急性甲基苯丙胺处理所致小鼠活动增强效应的影响。小鼠腹泻注射甲基苯丙胺2mg·kg~(-1)·d~(-1),连续7d,建立甲基苯丙胺诱导的小鼠行为敏化模型,观察噻诺啡对小鼠行为敏化的影响。结果:单次皮下注射噻诺啡(0.0625～1.0mg·kg~(-1))可剂量依赖性地抑制小鼠的自主活动(P<0.05),连续给药7d,噻诺啡对小鼠自主活动的抑制作用不产生敏化,而耐受。噻诺啡对急性甲基苯丙胺处理所致小鼠的高活动性无明显影响。噻诺啡对甲基苯丙胺诱导的小鼠行为敏化的形成和表达无显著作用,但可剂量依赖性地抑制敏化的转化(P<0.05或P<0.01)。结论:噻诺啡对中枢神经系统具有抑制作用,并且可以阻止甲基苯丙胺诱导小鼠产生行为敏化的转化过程,提示噻诺啡可能对甲基苯丙胺的成瘾行为具有一定的干预作用。     

噻诺啡灌胃给药对小鼠甲基苯丙胺行为敏化的影响

目的:探讨新型丁丙诺啡同系物-噻诺啡,灌胃(ig)给药对小鼠甲基苯丙胺行为敏化过程的影响。方法:测定小鼠的自主活动,观察ig噻诺啡对小鼠的自主活动及单次给予甲基苯丙胺所诱导的小鼠高活动性的影响。建立甲基苯丙胺诱导的小鼠行为敏化模型,观察噻诺啡对行为敏化形成、转化及表达的影响。结果:(1)单次ig噻诺啡(1 2 5 - 5 0mg·kg-1)可剂量依赖性地抑制小鼠的自主活动(P <0 . 0 1) ,其作用多次给药后产生耐受;(2 )噻诺啡对单次给予甲基苯丙胺所诱导的小鼠的高活动性无明显影响;(3)噻诺啡对甲基苯丙胺诱导小鼠行为敏化的形成和表达无明显作用,却可显著抑制敏化的转化过程(P <0 . 0 5 )。结论:ig噻诺啡可抑制小鼠中枢神经系统,阻断甲基苯丙胺诱导小鼠产生行为敏化的转化过程,提示噻诺啡对甲基苯丙胺的成瘾行为具有一定的干预作用。     

A new buprenorphine analogy, thenorphine, inhibits morphine-induced behavioral sensitization in mice

AIM: To investigate effects of thenorphine, a new compound of partial agonist of μ-opioid receptor, on the loco-motor activity and the behavioral sensitization to morphine in mice. METHODS: Locomotor activity was observed after administration of thenorphine or co-administration of thenorphine and morphine in mice. Mice were induced behavioral sensitization to morphine by intraperitoneal injection of 20 mg/kg morphine once daily for 7 d. Thenorphine was co-administrated with morphine to observe the effects of thenorphine on the development, transfer and expression of morphine-induced behavioral sensitization. RESULTS: A single dose of thenorphine (0.0625, 0.25, and 1.0 mg/kg) could dose-dependently inhibit the locomotor activity in mice (P<0.05), repeated administrations of thenorphine, however, were not able to induce locomotor sensitization, but induced tolerance. Pretreatment with thenorphine 30 min prior to morphine effectively inhibited the psychomotor effect of morphine in mice (P<0.01). Co-adminis     

Morphine-induced sensitization in mice: changes in locomotor activity by prior scheduled exposure to GABAA receptor agents

This study investigated the effects of a gamma-amino-butyric acid type A (GABAA) receptor agonist and antagonist on morphine-induced locomotor sensitization in male albino mice. Subcutaneous administration to mice of a high dose of morphine (30 mg/kg), but not lower doses (5, 10 and 20 mg/kg) increased locomotion. The maximum locomotor activity was achieved during a 20-min measurement period. The locomotor response to a low dose of morphine (5 mg/kg, subcutaneously) given on day 9 was enhanced in mice pretreated with morphine (7.5, 15 and 30 mg/kg/day x 3 days), indicating that sensitization had developed. Three-day intracerebroventricular (i.c.v.) administration of the GABAA receptor agonist, muscimol (0.025, 0.05, 0.1 and 0.2 microg/mouse/day) significantly decreased both morphine-induced motor stimulation and locomotor sensitization. On the other hand, a 3-day pretreatment with the GABAA-receptor antagonist, bicuculline (0.25, 0.5 and 1 microg/mouse/day) reduced morphine (15 mg/kg)-induced locomotor sensitization. Repeated i.c.v. injections of a lower dose of bicuculline (0.25 microg/mouse/day x 3 days) by itself also decreased morphine-induced locomotion. Furthermore, repeated i.c.v. administration of bicuculline (0.25, 0.5 and 1 microg/mouse/day x 3 days) decreased the effect of i.c.v. injection of muscimol (0.1 microg/mouse/day x 3 days) on locomotor activity induced by morphine (5 mg/kg) in both control and sensitized mice. The magnitude of this response was, however, variable. The results indicate that GABAA receptors might be involved in the acquisition of morphine-induced sensitization.     

Role of nitric oxide in the acquisition and expression of apomorphine- or morphine-induced locomotor sensitization

In the present study, the effects of L-arginine, a nitric oxide (NO) precursor, and N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, on apomorphine- or morphine-induced locomotor sensitization in male albino mice were investigated. Our data showed that subcutaneous (s.c.) injection of apomorphine (2-10 mg/kg) or morphine sulphate (5-50 mg/kg) significantly increased locomotor behaviour in a dose-dependent manner. Intraperitoneal (i.p.) administration of L-arginine (100 mg/kg) increased locomotor activity, whereas L-NAME (20 mg/kg) decreased it. L-Arginine and L-NAME increased and decreased apomorphine- or morphine-induced locomotions, respectively. The locomotor behavioural response was enhanced in mice pretreated with apomorphine (2 mg/kg, daily x3 days) or morphine (10 mg/kg, daily x3 days) alone, indicating that sensitization had developed. Administration of L-arginine 30 min before each of three daily doses of apomorphine or morphine increased the development of sensitization, while administration of L-NAME 30 min before each of three daily doses of apomorphine or morphine decreased the acquisition of sensitization induced by apomorphine or morphine. Administration of L-arginine significantly increased and L-NAME significantly and dose-dependently decreased the expression of both apomorphine- and morphine-induced sensitization. The results indicate that NO may be involved in the acquisition and expression of apomorphine- or morphine-induced sensitization.     

Inhibitory effects of glycine on morphine-induced hyperactivity,reverse tolerance and postsynaptic dopamine receptor supersensitivity in mice

The effects of glycine on morphine-induced hyperactivity, reverse tolerance and postsynaptic dopamine receptor supersensitivity in mice was examined. A single administration of morphine (10 mg/kg, s.c.) induced hyperactivity as measured in mice. The morphine-induced hyperactivity was inhibited by pretreatment with glycine (100, 200 and 400 mg/kg, i.p.). In addition, it was found repeated administration of morphine (10 mg/kg, s.c.) to mice daily for 6 days caused an increase in motor activity which could be induced by a subsequent morphine dose, an effect known as reverse tolerance or sensitization. Glycine (100, 200 and 400 mg/kg, i.p.) also inhibited morphine-induced reverse tolerance. Mice that had received 7 daily repeated administrations of morphine also developed postsynaptic dopamine receptor supersensitivity, as shown by enhanced ambulatory activity after administration of apomorphine (2 mg/kg, s.c.). Glycine inhibited the development of postsynaptic dopamine receptor supersensitivity induced by repeated administration of morphine. It is suggested that the inhibitory effects of glycine might be mediated by dopaminergic (DAergic) transmission. Accordingly, the inhibition by glycine of the morphine-induced hyperactivity, reverse tolerance and dopamine receptor supersensitivity suggests that glycine might be useful for the treatment of morphine addiction.     

Morphine-induced antinociception in the formalin test: sensitization and interactions with D1 and D2 dopamine receptors and nitric oxide agents

In this study, the effects of dopamine receptor antagonists and nitric oxide agents on morphine-induced sensitization in the formalin test in mice have been investigated. Repeated daily intraperitoneal administration of morphine (30 mg/kg for 3 days) followed by a 11-day wash out period increased morphine-induced antinociception in the formalin test, which may be due to sensitization. The antinociceptive response to higher doses of morphine (6 and 9 mg/kg) but not 3 mg/kg was significantly increased in sensitized animals compared with control groups. Pretreatment of animals with an opioid receptor antagonist, naloxone (4 mg/kg), during repeated administration of morphine, attenuated the morphine-induced sensitization. In the second part of the study, the animals received SCH23390 (D1 receptor antagonist), sulpiride (D2 receptor antagonist), L-Arg (nitric oxide precursor) and NG-nitro-L-Arg methylester (nitric oxide synthase inhibitor) during repeated morphine administration, to evaluate the role of dopamine receptor antagonists and nitric oxide agents in this phenomenon. Pretreatment of animals with NG-nitro-L-Arg methylester (20 mg/kg) and sulpiride (100 mg/kg) during morphine sensitization decreased the antinociceptive response to higher doses of morphine in the formalin test. It is concluded that D2 dopamine receptor and nitric oxide mechanisms may be involved at least partly in morphine-induced sensitization in the formalin test.     

Influence of morphine and dopamine receptor sensitization on locomotor activity in mice

In the present study, the influence of morphine- and dopamine receptor antagonists-induced sensitization on morphine-induced locomotion in mice was investigated. Morphine (30, 40 and 50 mg/kg) increased, while lower doses of the opioid (10 and 20 mg/kg) decreased locomotor activity of mice. Subchronic repeated pretreatment of animals with morphine showed an increase in locomotion induced by the opioid. Clozapine reduced locomotor activity induced by morphine in both the na?ve and subchronic morphine-treated animals. Subchronic pretreatment of clozapine also caused an increase in the locomotion induced by morphine. Sulpiride also decreased locomotion induced by morphine and its subchronic administration of the drug caused an increase in morphine- or apomorphine-induced locomotion. Co-administration of clozapine with sulpiride did not elicit potentiation in inhibiting the morphine effect. The D2 receptor mRNA expression was also increased by repeated morphine administration. It may be concluded that morphine-induced sensitization may be due to increase in D2 receptor mRNA expression. Sulpiride and clozapine may induce sensitization and also inhibit morphine-induced locomotion through their dopamine receptor blocking properties.     

Effects of repeated exposure to morphine in adolescent and adult male C57BL/6J mice: age-dependent differences in locomotor stimulation,sensitization, and body weight loss

Rationale

Given evidence for age-related differences in the effects of drugs of abuse, surprisingly few preclinical studies have explored effects of opioids in adolescents (versus adults).

Objectives

This study compared the motor stimulating and ataxic effects of repeatedly administered morphine in adolescent, late adolescent, and adult mice.

Methods

Mice were treated with saline or morphine (10–100 mg/kg, i.p.) once per day for 4 days, and morphine (3.2–56 mg/kg)-induced locomotion was assessed 3 days or 5 weeks later. Different mice were treated repeatedly with morphine and ataxia was measured.

Results

Acute administration of morphine increased locomotion more in adolescents than in adults. Repeated morphine enhanced morphine-induced locomotion, assessed 3 days later, to a similar extent in each age group (minimum effective dose 17.8 mg/kg). This sensitization was still evident 5 weeks later when the adolescents had become adult, but was smaller and occurred at a higher dose (56 mg/kg). In animals treated repeatedly with morphine as adults, sensitization was no longer apparent 5 weeks later. Intermittent morphine was at least 10-fold less potent to produce body weight loss in adolescents than in adults. Repeated morphine did not alter morphine-induced ataxia at any age.

Conclusions

Compared with adults, adolescents were more sensitive to the acute locomotor stimulating effects of morphine and to its long-lasting locomotor sensitizing effects, consistent with overactivity of dopamine systems during adolescence. In contrast, adolescents were less sensitive than adults to body weight loss induced by intermittent morphine, an effect indicative of morphine withdrawal in adult rodents.