OBJECTIVETo investigate the changes in CREB (cAMP response element binding protein) in hippocampus, PFC (prefrontal cortex) and NAc (nucleus accumbens) during three phases of morphine induced CPP (conditioned place preference) in rats, and to elucidate the role of CREB during the progress of conditioned place preference.

METHODSMorphine induced CPP acquisition, extinction and drug primed reinstatement model was established, and CREB expression in each brain area was measured by Western Blot methods.

RESULTSEight alternating injections of morphine (10 mg/kg) induced CPP, and 8 d saline extinction training that extinguished CPP. CPP was reinstated following a priming injection of morphine (2.5 mg/kg). During the phases of CPP acquisition and reinstatement, the level of CREB expression was significantly changed in different brain areas.

CONCLUSIONIt was proved that CPP model can be used as an effective tool to investigate the mechanisms underlying drug-induced reinstatement of drug seeking after extinction, and that morphine induced CPP and drug primed reinstatement may involve activation of the transcription factor CREB in several brain areas, suggesting that the CREB and its target gene regulation pathway may mediate the basic mechanism underlying opioid dependence and its drug seeking behavior.

Analgesics, Opioid ; pharmacology ; Animals ; Blotting, Western ; Conditioning (Psychology) ; Conditioning, Operant ; drug effects ; Cyclic AMP Response Element-Binding Protein ; biosynthesis ; Hippocampus ; metabolism ; Male ; Morphine ; pharmacology ; Nucleus Accumbens ; metabolism ; Prefrontal Cortex ; metabolism ; Rats ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVE: To study the role of dopamine D3 receptor involved in the amphetamine-induced conditioned place preference (CPP) in mice. METHODS: The CPP was observed in D3 receptor knock-out (D3RKO) mice and C57BL/6 wild-type control mice after administration of amphetamine. The data were analyzed with a two-way ANOVA using the SPSS 13.0 software. RESULTS: D3RKO mice showed a significant amphetamine-induced CPP (P<0.001), compared with the ones administered with saline in C57BL/6 control mice. CONCLUSION The results indicate that amphetamine can produce significant CPP in dopamine D3 receptor knock-out mice, suggesting that amphetamine-induced addiction can be inhibited by dopamine D3 receptor.
Amphetamine/pharmacology* ; Animals ; Behavior, Animal/drug effects* ; Conditioning, Operant/drug effects* ; Disease Models, Animal ; Female ; Gene Knockout Techniques ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Motor Activity/drug effects* ; Reaction Time ; Receptors, Dopamine D3/physiology*

OBJECTIVETo evaluate the effects of Caulis Sinomenii and sinomenine on conditioned place preference (CPP) induced by morphine and brain histamine level in mice.

METHODSSixty mice were randomized into 6 equal groups and morphine (Mor) was injected subcutaneously (9 mg/kg) for 6 consecutive days to induce CPP using a shuttle box. Since the 4th day of training, the mice in 5 of the groups were treated for 3 consecutive days with Caulis Sinomenii (10 g/kg), sinomenine (60 mg/kg), diphenhydramine (30 mg/kg), CP48/80 (5 mg/kg) and L-histidine (750 mg/kg) in addition to morphine (9 mg/kg) treatment, respectively, leaving the other group with exclusive morphine treatment. Another 10 mice received saline injection to serve as saline control group. The content of histamine (HA) in the mouse brain was measured by fluorospectrophotometry.

RESULTSIn morphine group, the mice showed significantly extended stay in morphine-paired compartment whose HA content in the brain was markedly increased (P<0.01). Treatment with Caulis Sinomenii and sinomenine resulted in significantly reduced time of stay in morphine-paired compartment and brain HA level (P<0.01).

CONCLUSIONCPP induced by morphine in mice is associated with increased HA level in the brain. Caulis Sinomenii and sinomenine can suppress the acquisition of place preference induced by morphine and modulate HA level in the central nervous system in morphine-dependent mice.

Animals ; Arginine ; pharmacology ; Brain ; drug effects ; metabolism ; Conditioning, Operant ; drug effects ; physiology ; Diphenhydramine ; pharmacology ; Histamine ; metabolism ; Male ; Mice ; Morphinans ; pharmacology ; Morphine ; toxicity ; Morphine Dependence ; etiology ; physiopathology ; Motor Activity ; drug effects ; Random Allocation ; Sinomenium ; chemistry

OBJECTIVETo study the acting mechanism of anti-morphine conditioned place preference (CPP) between aqueous extract of Corydalis yanhusuo and L-THP and compare their effects.

METHODThe CPP model was established by injecting morphine in rats with a increasing dose for 10 days, with the initial dose of 10 g x kg(-1) and the final dose of 100 g x kg(-1), 10 mg x kg(-1) was increased each day, thus 100 mg x kg(-1) was injected by d 10. Having been treated with differential doses (2, 1 and 0.5 g x kg(-1)) of C. yanhusuo (containing L-THP: 0.153, 0.077 and 0.038 mg x kg(-1) respectively) and L-THP (3.76, 1.88 and 0.94 mg x kg(-1)) for six days, the CPP effect in rats was detected. Both colorimetry and immunohistochemistry methods were adopted to detect the content of glutamate neurotransmitter in each brain region and the expression of NR2B in VTA-NAc-PFC neuroanatomical circuit.

RESULTCompared with the physiological saline treatment group, C. yanhusuo (2, 1 g x kg(-1)) and L-THP (3.76 and 1.88 mg x kg(-1)) groups showed a notably shorter retention period of rats in white boxes (morphine-accompanied boxes) (P < 0.05 or P < 0.01) and remarkably lower glutamic acid content in VTA, NAc and PFC and NR2B expression.

CONCLUSIONBoth C. yanhusuo and L-THP can substantially inhibit the effect of morphine CPP, reduce the increasing glutamic acid content in VTA-NAc-PFC neuroanatomical circuit and down-regulated NR2B expression, which may be one of mechanisms on reducing the effect of morphine CPP. C. yanhusuo preparations containing L-THP (1 x ) showed 24-fold effect of L-THP monomer of single application in terms of the behaviouristics of inhibitory effect on CPP as well as the similarity in terms of transmitter glutamic acid of in VTA-NAc-PFC neuroanatomical circuit and pharmacological mechanism of NR2B.

Animals ; Berberine Alkaloids ; therapeutic use ; Conditioning, Operant ; drug effects ; Corydalis ; chemistry ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; therapeutic use ; Humans ; Male ; Morphine ; antagonists & inhibitors ; Morphine Dependence ; drug therapy ; psychology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of clobenpropit and histidine on reinstatement of morphine-induced conditioned place preference (CPP) in rats.

METHODSThe persistence, extinction and reinstatement of morphine-induced CPP were established.In clobenpropit group three different doses of clobenpropit (2, 5 and 10 microg/rat, i.c.v.) were administered 15 min after morphine (1 mg/kg, i.p.) was injected. In histidine group histidine (100, 200, 500 mg/kg) was given 1 h prior to morphine treatment (1 mg/kg i.p).

RESULTThe CPP was reinstated by priming injection of 1 mg/kg morphine. Clobenpropit (5, 10 microg/rat) significantly inhabited the reinstatement by a priming dose of morphine-induced CPP compared with the morphine control group; histidine (100, 200, 500 mg/kg) significantly inhibited the reinstatement in a dose-dependent manner.

CONCLUSIONClobenpropit and histidine inhibit the revival of morphine-induced CPP in a dose dependent manner, indicating that endogenous histamine may inhibit relapse of morphine to some extent.

Animals ; Conditioning, Operant ; drug effects ; Histidine ; metabolism ; Imidazoles ; pharmacology ; Male ; Morphine Dependence ; physiopathology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Cell Surface ; antagonists & inhibitors ; Substance Withdrawal Syndrome ; physiopathology ; Thiourea ; analogs & derivatives ; pharmacology

OBJECTIVETo study and compare the effect of Corydalis yanhusuo and L-THP on dopamine neurotransmitter and D2 receptor of reward circuitry in various cerebral areas of conditioned place preference model rats and the comparison of their effects.

METHODThe CPP model was established by injecting morphine in rats with increasing doses for 10 days. The initial dose of 10 mg x kg(-1), and the final dose of 100 mg x kg(-1), with 10 mg x kg(-1) increased each day. At 48 h after the final training, CPP was adopted to detect the successful establishment of the model. On the same day (12 d), they were orally administered with 2, 1, 0.5 g x kg(-1) C. yanhusuo (containing 0.153, 0.077 and 0.038 mg L-THP) and L-THP (3.76, 1.88, 0.94 mg x kg(-1)) for six days. On 18 d, CPP test was performed again. Next day, HPLC was adopted to determine the content of dopamine neurotransmitters of reward circuitry in VTA-NAc-PFC; Immunohistochemistry and Western blotting were adopted to detect the expression of D2 receptors.

RESULTCompared with the physiological saline treatment group, C. yanhusuo (2, 1 g x kg(-1)) and L-THP (3.76, 1.88 mg x kg(-1)) groups showed that rats stayed in a notably shorter period in white boxes (morphine-accompanied boxes) (P < 0.01 or P < 0.05), and revealed a remarkably lower dopamine content in VTA, NAc and PFC and the significant increase in the expression of D2 receptor (P < 0.01 or P < 0.05).

CONCLUSIONThe down-regulation of the increased dopamine content in reward nervous circuitry and the up-regulation of the expression of D2 receptor may be one of mechanisms of C. yanhusuo and L-THP in accelerating the recession of morphine's CPP effect Regarding the inhibition of morphine's CPP effect and the effect on dopamine system, the effect of C. yanhusuo traditional Chinese medicine containing one-fold L-THP monomer is equal to that of the independent application of around 24-fold L-THP monomer.

Animals ; Berberine Alkaloids ; administration & dosage ; Brain ; drug effects ; metabolism ; physiopathology ; Conditioning, Operant ; drug effects ; Corydalis ; chemistry ; Dopamine ; metabolism ; Humans ; Male ; Morphine ; adverse effects ; Plant Extracts ; administration & dosage ; Rats ; Rats, Sprague-Dawley ; Receptors, Dopamine D2 ; genetics ; metabolism ; Substance-Related Disorders ; drug therapy ; genetics ; metabolism ; psychology

Animals always seek rewards and the related neural basis has been well studied. However, what happens when animals fail to get a reward is largely unknown, although this is commonly seen in behaviors such as predation. Here, we set up a behavioral model of repeated failure in reward pursuit (RFRP) in Drosophila larvae. In this model, the larvae were repeatedly prevented from reaching attractants such as yeast and butyl acetate, before finally abandoning further attempts. After giving up, they usually showed a decreased locomotor speed and impaired performance in light avoidance and sugar preference, which were named as phenotypes of RFRP states. In larvae that had developed RFRP phenotypes, the octopamine concentration was greatly elevated, while tβh mutants devoid of octopamine were less likely to develop RFRP phenotypes, and octopamine feeding efficiently restored such defects. By down-regulating tβh in different groups of neurons and imaging neuronal activity, neurons that regulated the development of RFRP states and the behavioral exhibition of RFRP phenotypes were mapped to a small subgroup of non-glutamatergic and glutamatergic octopaminergic neurons in the central larval brain. Our results establish a model for investigating the effect of depriving an expected reward in Drosophila and provide a simplified framework for the associated neural basis.
Acetates ; pharmacology ; Animals ; Animals, Genetically Modified ; Avoidance Learning ; physiology ; Biogenic Amines ; metabolism ; Conditioning, Operant ; physiology ; Drosophila ; physiology ; Drosophila Proteins ; genetics ; metabolism ; Feeding Behavior ; drug effects ; physiology ; Instinct ; Larva ; physiology ; Locomotion ; drug effects ; genetics ; Nervous System ; cytology ; Neurons ; physiology ; Octopamine ; metabolism ; RNA Interference ; physiology ; Reward ; Statistics, Nonparametric ; Transcription Factors ; genetics ; metabolism