AIMTo investigate the effects and the possible mechanism of cocaine on the neurons of lateral habenular nucleus (LHb).

METHODSWe observed the effects on c-Fos protein expression in lateral habenular nucleus and medial habenular nucleus after injecting cocaine into a belly cavity and spontaneous and evoked discharge of pain-correlative unit through iontophoresis of cocaine into LHb. The delayed rectifier K+ current was recorded in the acute isolated LHb neuron in whole-cell mode.

RESULTS(1) The c-Fos protein expression was increased by cocaine treatment in LHb, but little effect in MHb. (2) Iontophoresis of cocaine into LHb increased the discharges of pain excitation unit and enhanced excitation response to noxious stimulation, but it decreased the discharges of pain inhibition unit and its responses to noxious stimulation in LHb. Cocaine inhibited the delayed rectifier K+ current.

CONCLUSIONCocaine can excite the LHb and increase its sensitivity. The probable mechanism is that cocaine inhibits the delayed rectifier K+ channels.

Animals ; Cocaine ; pharmacology ; Habenula ; drug effects ; metabolism ; physiology ; Proto-Oncogene Proteins c-fos ; metabolism ; Rats ; Rats, Wistar

OBJECTIVES: To establish a rapid determination method with LC-MS/MS for cocaine and its metabolite benzoylecgonine in hair. METHODS: Deuterated internal standards （cocaine-D₃ and benzoylecgonine-D₈） were added to the decontaminated hair. After the extraction by ultrasonication with methanol, the compounds were separated by the Restek Allure PFP propyl column, and cocaine and benzoylecgonine were simultaneously analysed in multiple reaction monitoring mode. RESULTS: The cocaine and benzoylecgonine in hair showed a good linearity in the range of mass fraction between 0.02 and 10.00 ng/mg with the limits of detection of 0.01 ng/mg. CONCLUSIONS The developed method is simple and rapid with a good selectivity, which is suitable for the determination of cocaine and its metabolite benzoylecgonine in hair.
Chromatography, High Pressure Liquid ; Chromatography, Liquid/methods* ; Cocaine/metabolism* ; Hair/metabolism* ; Humans ; Reference Standards ; Reproducibility of Results ; Tandem Mass Spectrometry/methods*

Pseudocholinesterase is known to be involved in the metabolism of succinylcholine, mivacurium, procaine, chloroprocaine, tetracaine, cocaine, heroin, and other drugs, although the physiologic function has not been well established. Prolonged neuromuscular block following administration of succinylcholine correlates with very low or genetically variant cholinesterase activity. The determination of pseudocholinesterase activity is of importance to the anesthetist in order to predict the susceptibility of the patient to the muscle relaxant, succinylcholine. The purpose of this study was to investigate the change of pseudocholinesterase level during cardiopulmonary bypass(CPB) for open heart surgery with hemodilution and hypothermia. Seven venous blood samples before induction of anesthesia(control), during CPB, and until the fifth postoperative day in 12 patients who underwent open heart surgery were taken. The pseudocholinesterase level was measured by Wako kit and JASCO UVIDEC 77 clinical spectrophotometer. The results were as follows ; 1) The control hematocrit was 40.32+/-6.21% and decreased to 23.72+/-1.86% immediately after the start of CPB(p<0.01) and to 22.42+/-1.93 % 30 minutes after the start of CPB(p<0.01). 2) The control pseudocholinesterase value of 1296.67+/-251.03 IU/L decreased to 915.67+/-228.16 IU/L immediately after the start of CPB(p<0.01), and to 727.83+/-197.58 IU/L 30 minutes after the start of CPB(p<0.01). 3) The mean values of pseudocholinesterase level immediately posteratively, on the first postoperative, and the third postoperative days were 1488.50+/-333.52 IU/L, 1913. 17+614.50 IU/L and 1620.92+/-458.82 IU/L, respectively, and those were significantly increased from the control value(p<0.05, p<0.01, and p<0.01, respectively). 4) The mean value of pseudocholinesterase level on the fifth postoperative day was 1392.25+/-271.69 IU/L, which was not significantly different from the control valule. 5) Transfused units of whole blood, packed red cells, and fresh frozen plasma were 2.8+/-1.4, 3.2 +/-1.0, 3.4+/-0.9, respectively.
Cardiopulmonary Bypass* ; Cholinesterases ; Cocaine ; Hematocrit ; Hemodilution ; Heroin ; Humans ; Hypothermia ; Metabolism ; Neuromuscular Blockade ; Plasma ; Procaine ; Pseudocholinesterase* ; Succinylcholine ; Tetracaine ; Thoracic Surgery

Cocaine analogue, CFT (2beta-carbomethoxy-3beta-(4-fluorophenyl) tropane) binding to dopamine transporter (DAT) in different species is quite heterogeneous. CFT is scarcely detected in bovine DAT whereas it is conspicuous in humans. To examine the structural basis for this functional discrepancy, we analyzed transporter chimeras of these two DATs. The CFT binding activities are avid in all of the chimeric DATs of which both of the 3rd and the 6-8th transmembrane domain (TM) are composed of human DAT sequences. On the contrary, CFT binding activities were scarcely detected if either or both of two regions are replaced with bovine sequences. These findings indicate that the CFT binding absolutely requires human DAT sequences, at least, in the regions encompassing the 3rd and 6-8th transmembrane domain (TM), and that these regions might contribute to form the 3-dimensional pocket for CFT binding.
Animal ; Cattle ; Chimeric Proteins/genetics/metabolism ; Cocaine/*analogs & derivatives/*metabolism ; Human ; Membrane Transport Proteins/*genetics/*metabolism ; Protein Binding ; Protein Structure, Tertiary

OBJECTIVE: To examine the effects of cocaine on the activities of ATPase, LDH and SDH in cultured mouse splenocytes in vitro. METHODS: The ATPase, LDH and SDH activities in mouse splenocytes were detected at day 7 after continuous culturing the mouse cells exposed to cocaine hydrochloride in final concentration of 10, 20 and 100 microg/mL in vitro. RESULTS: The activities of ATPase, LDH and SDH in mouse splenocytes exposed to cocaine hydrochloride in final concentration of 10, 20 and 100 microg/mL were significantly decreased after continuous culturing for 7 days. CONCLUSION The present study demonstrated that cocaine could inhibit the activities of ATPase, LDH and SDH in cultured splenocytes in vitro.
Adenosine Triphosphatases/metabolism* ; Animals ; Cells, Cultured ; Cocaine/pharmacology* ; Dose-Response Relationship, Drug ; L-Lactate Dehydrogenase/metabolism* ; Male ; Mice ; Mice, Inbred Strains ; Spleen/enzymology* ; Succinate Dehydrogenase/metabolism*

Adult rats were implanted with sleep-wake recording electrodes in our experiments. Polygraphic signs of undisturbed sleep-wake activities were recorded for 24 h before cocaine administration, cocaine withdrawal day 1 (acute), day 8 (subacute), and day 14 (subchronic). Western blot method was performed to examine the expression levels of adenosine receptor subtypes in hypothalamus and cerebellum. Non rapid eye movement (NREM) sleep was significantly increased during nighttime (P < 0.01) and daytime (P < 0.05) on withdrawal day 8. The increase of NREM sleep was significant during nighttime (P < 0.01) and slight during daytime on withdrawal day 14, whereas both daytime and nighttime rapid eye movement (REM) sleeps were reduced markedly (P < 0.01) on withdrawal day 8 and 14. In addition, A2A receptor level was significantly enhanced on cocaine withdrawal day 8 and day 14 (P < 0.05), whereas A1 receptor level reduced markedly on withdrawal day 14 (P < 0.05). However, compared with that in the control group, no significant changes existed among adenosine A1, A2A and A2B receptors in rat cerebellum on cocaine withdrawal day 1, day 8 and day 14. Our findings suggest that sleep disorder caused by subacute and subchronic cocaine abstinence may be associated with over-expression of adenosine A2A receptor in rat hypothalamus to some extent.
Animals ; Cocaine ; adverse effects ; Dyssomnias ; chemically induced ; Electroencephalography ; Hypothalamus ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Receptor, Adenosine A2A ; metabolism ; Substance Withdrawal Syndrome

A sensitive LC-MS/MS method to determine cocaine and its major metabolite benzoylecgonine in guinea pig' s hair has been established. About 20 mg of decontaminated hair sample was hydrolyzed with 0. 1 mol x L(-1) HCl at 50 degrees C overnight, in the presence of cocaine-d3 and benzoylecgonine-d8 used as internal standards, and then extracted with dichlormethane. The analysis was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Positive electrospray ionization (ESI +) and multiple reactions monitoring (MRM) mode were used. The limit of detection (LOD) for cocaine and benzoylecgonine was 1 pg x mg(-1). The calibration curves of extracted standards were linear over the range from 5 pg x mg(-1) to 250 pg x mg(-1) (r2 > or = 0.9997). The method was validated and applied to the analysis of guinea pig's hair after a single dose administration of cocaine hydrochloride. Cocaine and benzoylecgonine were not only detected, but also quantified in guinea pigs hair.
Animals ; Chromatography, High Pressure Liquid ; Cocaine ; administration & dosage ; analogs & derivatives ; analysis ; metabolism ; Guinea Pigs ; Hair ; chemistry ; metabolism ; Spectrometry, Mass, Electrospray Ionization ; Tandem Mass Spectrometry

The intense associative memories that develop between cocaine-paired contexts and rewarding stimuli make addiction hard to cure by contributing to cocaine seeking and relapse. So it's of great importance to examine the neurobiological basis of addiction memory. Cocaine conditioned place preference (CPP) used in this study is a form of Pavlovian conditioning which can establish associations between drug and contextual factors. c-Fos and Zif268 are commonly used immediate early gene (IEG) makers to identify neurons that are activated after a stimulus or behavioral conditioning. This study was designed to reveal neuronal c-Fos, Zif268 expression pattern in 10 brain regions following cocaine context-associated reward memory retrieval in mice, combining animal behavioral study and immunofluorescence method. C57BL/6 mice were randomly divided into 3 groups: Saline retrieval, Cocaine retrieval, and No retrieval of cocaine groups. Cocaine retrieval and No retrieval of cocaine underwent CPP training (one side paired with cocaine, and the other side with saline) except that No retrieval of cocaine group didn't undergo CPP test. Saline retrieval group received saline injections (i.p) on both sides. The results showed that: Neuronal c-Fos, Zif268 protein expression levels in nucleus accumbens (NAc) core both were elevated in Cocaine retrieval group compared with those in Saline retrieval (Control) group during cocaine context-associated reward memory retrieval. Zif268 protein expression level in basolateral amygdala (BLA) was also elevated in Cocaine retrieval group compared with that in control mice. Elevation was not seen in other regions such as hippocampus, prefrontal cortex (PFC). Thus, NAc core and BLA were activated during cocaine context-associated reward memory retrieval. The results suggest that neurons that are activated in NAc core and BLA are crucial basis of cocaine context-associated reward memory.
Animals ; Basolateral Nuclear Complex ; cytology ; Cocaine ; pharmacology ; Conditioning (Psychology) ; Early Growth Response Protein 1 ; metabolism ; Hippocampus ; Memory ; Mice ; Mice, Inbred C57BL ; Neurons ; metabolism ; Nucleus Accumbens ; metabolism ; Prefrontal Cortex ; Proto-Oncogene Proteins c-fos ; metabolism ; Reward

The aim of the experiments was to develop and characterize a murine model for investigating the effects of prenatal cocaine exposure on the mother and fetus. Pregnant mice were separated into three groups: group 1 was treated with cocaine HCl at 10 mg/kg twice daily (COC); group 2 was treated with saline at 10 ml/kg twice daily (SAL); and group 3 was pair-fed with the COC dams and was injected with saline following the same schedule (SPF) from embryonic day (E) 8 to 17. We utilized high-pressure liquid chromatography (HPLC) with UV detector and electrochemical detector to test the concentrations of cocaine, dopamine and serotonin, as well as HE staining to observe morphological alterations of liver and placenta. Though less food intake and lower weight gain were observed in COC and SPF groups but not in SAL dams, lower fetal body weight and brain weight were only seen in COC offspring. Pharmacological analysis revealed that cocaine was found in fetal plasma at 15 min following intraperitoneal administration on E17, accompanied with elevated concentrations of dopamine (DA) and serotonin (5-HT) in fetal brain. We also observed morphological changes in liver and placenta of cocaine-exposed fetuses. The present study indicates that pregnancy cocaine exposure can lead to maternal undernutrition and developmental abnormality of the fetal brain, liver and placenta. It is suggested that the developmental abnormality of the fetuses induced by cocaine is due to the toxicological effect of cocaine but not to maternal undernutrition.
Animals ; Brain ; metabolism ; pathology ; Cocaine ; adverse effects ; blood ; Disease Models, Animal ; Dopamine ; metabolism ; Female ; Fetus ; drug effects ; pathology ; Liver ; pathology ; Malnutrition ; Maternal Exposure ; adverse effects ; Maternal Nutritional Physiological Phenomena ; Mice ; Mothers ; Placenta ; pathology ; Pregnancy ; Serotonin ; metabolism

G protein-coupled receptor kinase 5 (GRK5) plays an important role in the regulation of GPCR-transduced signals. Our previous study showed that acute administration of morphine could significantly increase GRK5 mRNA level in the cerebral cortex and hippocampus of the rat brain. The current study investigated the potential effects of acute administration of addictive drugs including morphine, heroine and cocaine on GRK5 mRNA level in the rat brain using in situ hybridization and analyzed the effects of acute and chronic morphine treatments on GRK5 protein level in the rat brain using Western blotting assay. Our results showed that 2 h after the initial morphine (10 mg/kg), cocaine (15 mg/kg) and heroine (1 mg/kg) treatment, the mRNA level of GRK5 in the parietal cortex increased about 110% (P<0.01), 70% (P<0.05) and 100% (P<0.01), respectively. In the temporal cortex, GRK5 mRNA level increased about 90% (P<0.01), 40% (P<0.05) and 80.0% (P<0.01), respectively . In the hippocampus, the mRNA level of GRK5 increased about 60% (P<0.01), 30% (P<0.05) and 80% (P<0.01). However, the mRNA level of GRK5 remained unchanged after acute morphine, cocaine or heroine treatment. In the cerebral cortex of the rat brain, the acute administration of morphine (NS-Mor) increased GRK5 protein level by about 60% while the chronic morphine treatment (Mor-Mor) increased GRK5 protein level even higher [about 130% compared with the control group (chronic saline treatment, NS-NS) group, P<0.01]. In the hippocampus, GRK5 protein level remained unchanged after acute administration of morphine (P>0.1),while the level of GRK5 protein tended to decrease after chronic morphine treatment (P=0.098). In the thalamus, acute morphine treatment caused no change in GRK5 protein level (P>0.1) while after chronic morphine treatment, GRK5 protein level decreased significantly (more than 90%, P<0.01), Taken together, our results indicate that addictive drugs can regulate GRK5 in the rat brain on protein level as well as on mRNA level and suggest that GRK5 may play a role in addiction of psychoactive substances.
Animals ; Brain ; metabolism ; Cocaine ; adverse effects ; G-Protein-Coupled Receptor Kinase 5 ; Heroin ; adverse effects ; Male ; Morphine ; adverse effects ; Protein-Serine-Threonine Kinases ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Substance-Related Disorders ; metabolism