It is the purpose of this study to determine the alterations of the metabolism on the feline spinal cord following trauma. Cats were anesthetized with ketamine hydrocloride and injured with a 400 gm-cm impact injury to L-2 level of spinal cord. Biochemical analysis of the injured segment revealed signicifant depletion in the concentrations of adenosine triphosphate(ATP) for the entire 24-hour postinjury period. Glucose concentrations were elevated significantly for the entire 24-hour period, and especially marked elevated between 8 and 24 hours. Lactate concentrations were elevated at 1 hour and between 1 and 4 hours. but especially significantly declined between 8 and 24 hours. This sequence of the metabolic changes suggested that anaerobic metabolism likely predominated for the initial 4 hours, and between 8 and 24 hours there appeared to be an increasing percentage of oxidative metabolism in the remaining metabolically viable tissues.
Adenosine ; Adenosine Triphosphate ; Animals ; Cats ; Energy Metabolism* ; Glucose ; Ketamine ; Lactic Acid ; Metabolism ; Spinal Cord Injuries* ; Spinal Cord*

OBJECTIVE: To select specific DNA aptamer for determining ketamine by FluMag-SELEX. METHODS: Based on magnetic beads with tosyl surface modification as solid carrier and ketamine as target, a random ssDNA library with total length of 78 bp in vitro was compounded. After 13 rounds screening, DNA cloning and sequencing were done. Primary and secondary, structures were analyzed. The affinity, specificity and Kd values of selected aptamer were measured by monitoring the fluorescence intensity. RESULTS: Two ssDNA aptamers (Apt#4 and Apt#8) were successfully selected with high and specific abilities to bind ketamine as target with Kd value of 0.59 and 0.66 μmol/L. The prediction of secondary structure was main stem-loop and G-tetramer. The stem was the basis of stability of aptamer's structure. And loop and G-tetramer was the key of specific binding of ketamine. CONCLUSION FluMag-SELEX can greatly improve the selection efficiency of the aptamer, obtain the ketamine-binding DNA aptamer, and develop a new method for rapid detection of ketamine.
Aptamers, Nucleotide/metabolism* ; DNA ; DNA, Single-Stranded/genetics* ; In Vitro Techniques ; Ketamine/metabolism* ; Oligonucleotides ; SELEX Aptamer Technique/methods*

The simultaneous administration of two or more drugs may result in interactions that increase or decrease the intended effects of one or both drugs. These interactions are often the result of induced alterations in the metabolism of the drugs. A wide variety of unrelated chemical agents are also capable of enhancing the activity of drug-metabolizing enzymea in the smooth-surfaced endoplasmic reticulum of the liver, and this accelerated metabolism alters the duration and intensity of action of a variety of pharmacological agents. Phenobarbital is a well known drug which promotes the metabolism of durgs in the liver. Some volatile or intravenous anesthetics were reported that enhance hepatic microspmal metabolism for themselves or for other drugs. Of these, Chang and Glazko (1974) reported that ketamine pretreatment did not influence the demethylation rate of drug metabolism and the liver weight in rats. However many opposite opinions have been expressed that ketamine enhanced mierosomal drug metabolism. Marietta et al (1975 and 1976) reported that the demethylating enzyme fraction of the ketamine-pretreated group was double of that of the control group in vitro. Thus we have made a study to evaluate the enhancement of drug metabolism induced by ketamine hydrochloride. Our experimental mice were divided into 4 groups, preteated with saline, phenobarbital, ketamine or carbon tetracbloride for 3 days. On the 1 st, 3 rd, 5th, 7th and 14th day after the pretreatment, we selected 10 mice randomly in each group, and hexobarbital(100mg/kg) was administered intraperitonealy. Then we evaluated the sleeping time, liver weight and microscopic findings of liver tissue. The results are as follows: 1) On the 1 st, 3 rd and 5th day after the pretreatment, the duration of hexobarbital induced hypnosis was significantly shorter in the ketamine-pretreated group than that in the control group, but not as long as that in the phenobarbital-pretreated group. 2) There was no remarkable change of the liver weight in the ketamine pretreated group. On the 1st and 3rd day after the pretreatment, liver weight was significanty increased in the phenobarbital and carbon tetrachloride pretreated groups. 3). Microscopic findings of liver showed no remarkable change in the ketamine-pretreated group, but there were significant cholestasis and hydrophic degeneration in the phenobarbital-and carbon tetrachloride-pretreated group respectively. In conclusion, it may be indicated that ketamine enhances hepatic microsomal drug metabolism because of shortening of the duration of hexobarbital-induced hypnosis.
Anesthetics, Intravenous ; Animals ; Carbon ; Carbon Tetrachloride ; Cholestasis ; Endoplasmic Reticulum ; Hexobarbital ; Hypnosis* ; In Vitro Techniques ; Ketamine ; Liver ; Metabolism ; Mice ; Phenobarbital ; Rats

The deficiency of aquaporin-4 (AQP4) has been reported to alter release of neurotransmitters in the mouse brain. However, the functional relevance of AQP4 in mediating essential components of the general anaesthetic state is unknown. The aim of the present study was to investigate the role of AQP4 in general anaesthesia in mice lacking AQP4. The hypnotic effects of propofol, ketamine, and pentobarbital in AQP4 knockout (KO) and CD1 control mice were evaluated using the behavioural endpoint of loss of righting reflex (LORR). The effects of propofol on extracellular levels of amino acids in prefrontal cortex of freely moving mice were investigated using microdialysis coupled to high performance liquid chromatography with fluorescent detection. The result showed that, after receiving ketamine or pentobarbital, LORR occurred at earlier time in KO mice than that in control animals. Intraperitoneal injection of ketamine or pentobarbital increased the duration of LORR. After the administration of propofol, the duration of LORR was significantly reduced in KO mice compared with that in controls. Propofol increased the extracellular levels of aspartate, glutamate, and GABA, but not taurine, in prefrontal cortex. There were significant differences of increase patterns of the three kinds of neurotransmitters between KO and WT mice. Notably, the duration of GABA level increase correlated with the duration of LORR in two genotypes of mice. These results provide in vivo evidence of different responses in time-dependent release of excitatory and inhibitory neurotransmitters in prefrontal cortex of the two genotypes of mice. It is suggested that changes in anaesthetic reactions in mice with AQP4 loss may be related to neurotransmitter regulation, and that normal functioning of AQP4 plays an important role in the maintenance of anaesthetic hypnosis.
Anesthetics, Intravenous ; pharmacology ; Animals ; Aquaporin 4 ; deficiency ; genetics ; Hypnotics and Sedatives ; pharmacology ; Ketamine ; pharmacology ; Mice ; Mice, Knockout ; Neurotransmitter Agents ; metabolism ; Pentobarbital ; pharmacology ; Prefrontal Cortex ; drug effects ; metabolism ; Propofol ; pharmacology

OBJECTIVE & BACKGROUND: It has been shown that cerebral ischemia alters brain monoamine metabolism. In an attempt to elucidate the. Mechanism for ischen-iiainduced release of neurotransmitters in vitro, we examined the ischemia-induced release of (3H) norepinephrine (NE) from cerebral cortex of the rat. RESULTS: Ischemia, deprivation of oxygen and glucose, induced significant (about 12% of total tissue content) release of (3H)NE from cerebral cortex in vitro. This ischemia-induced release of (3H)NE from cerebral cortex was significantly attenuated by 1 mM TTX (tetrodotoxin), 1. 2 mM Mg2+, 10 mM MK-801, 10 mM ketamine, NMDA receptor antagonist, 30 mM DNQX, a kainate/AMPA receptor antagonist, or a 30 mM carbetapentane, an inhibitor of glutarnate release Dantrolene(30 mM) and ryanodine (100 nM), inhibitors of intraceuular Ca2+ release, flunarizine(5 mM) and w-conotoxin (100 nM), inhibitors of N-type Ca2+ channels, significantly attenuated the ischeniiainduced release of (3H)NF, but verapamil (5mM), an inhibitor of L-type Ca2+ channels, did not. Nisoxetine(100 nM), a relative NE transporter blocker, significantly inhibited the ischemia-induced release of (3H) NE. Removal of Ca2+ from the incubation media potently increased ischemia-induced (3H)NE release. CONCLUSION: These results suggest that ischemia-evoked release of norepienphrine was caused by release of glutamate via activation of NMDA and non-NMDA receptors, and that Ca2+-dependent and -independent release processes are underlying in this phenomenon.
Animals ; Brain ; Brain Ischemia ; Cerebral Cortex* ; Dizocilpine Maleate ; Glucose ; Glutamic Acid ; Ischemia ; Ketamine ; Metabolism ; N-Methylaspartate ; Neurotransmitter Agents ; Norepinephrine* ; Oxygen ; Rats* ; Ryanodine ; Verapamil

PURPOSE: PET has some disadvantage in the imaging of small animal due to poor resolution. With the advent of microPET scanner, it is possible to image small animals. However, the image quality was not good enough as human image. Due to larger brain, cat brain imaging was superior to mouse or rat. In this study, we established the cat brain infarction model and evaluate it and its temporal change using microPET scanner. MATERIALS AND METHODS: Two adult male cats were used. Anesthesia was done with xylazine and ketamine HCl. A burr hole was made at 1cm right lateral to the bregma. Collagenase type IV 10 microliter was injected using 30 G needle for 5 minutes to establish the infarction model. 18F-FDG microPET (Concorde Microsystems Inc., Knoxville, TN) scans were performed 1, 11 and 32 days after the infarction. In addition, 18F-FDG PET scans were performed using human PET scanner (Gemini, Philips medical systems, CA, USA) 13 and 47 days after the infarction. RESULTS: Two cat brain infarction models were established. The glucose metabolism of an infarction lesion improved with time. An infarction lesion was also distinguishable in the human PET scan. CONCLUSION: We successfully established the cat brain infarction model and evaluated the infarcted lesion and its temporal change using 18F-FDG microPET scanner.
Adult ; Anesthesia ; Animals ; Brain Infarction* ; Brain* ; Cats* ; Collagenases ; Fluorodeoxyglucose F18 ; Glucose ; Humans ; Infarction ; Ketamine ; Male ; Metabolism ; Mice ; Needles ; Neuroimaging ; Positron-Emission Tomography ; Rats ; Xylazine

OBJECTIVETo study the effects of electroacupuncture (EA) on the changes of behavior after ketamine anesthesia, and changes of serum antibodies against beta-amyloid (Abeta) and Abeta protein in the hippocampus of aged rats, thus exploring the effects of EA on the cognitive dysfunction.

METHODSThirty 14-month old SD rats were randomly divided into 3 groups, i. e. , the control group (Group A), the ketamine anesthesia group (Group B), and the EA+ketamine anesthesia group (Group C), 10 in each group. 50 mg/kg katemine was intraperitoneally injected to rats in Group B and Group C, once daily for 7 successive days. EA was performed to rats in Group C from the 1st day of the experiment after rats awoke completely from anesthesia, twice daily for 7 successive days. Changes of the ratio of the swim time in the original platform quadrant to the total swim time and the escape latency phase were observed by Morris water maze. The peripheral blood was withdrawn by the end of the experiment. Serum anti-Abeta antibody contents were detected using enzyme-linked immunosorbent assay (ELISA). The expressions of Abeta in the hippocampus were detected using Westen blot.

RESULTSLong-term application of ketamine could lower aged rats' cognitive function. In the navigation test, the escape latency phase of rats in Group B was significantly prolonged ( P < 0.01) . On the 7th day of the experiment, the serum level of anti-Abeta antibodies was lower in Group B than in Group A (P < 0.05), while the serum level of anti-Abeta antibodies was significantly higher in Group C than in Group B (P < 0.01). On the 7th day of the experiment, the expression of Abeta in the hippocampus was higher in Group B than in Group A (P < 0.05).

CONCLUSIONEA could increase the contents of anti-Abeta antibodies in aged rats with ketamine anesthesia, decrease the expression of Abeta in the hippocampus, alleviate the deposition of Abeta, thus improving rats' cognitive dysfunction.

Amyloid beta-Peptides ; immunology ; Anesthesia ; adverse effects ; Animals ; Antibodies ; blood ; Cognitive Dysfunction ; therapy ; Electroacupuncture ; Female ; Hippocampus ; metabolism ; Ketamine ; adverse effects ; Male ; Maze Learning ; Rats ; Rats, Sprague-Dawley

The abuse of ketamine has gained popularity in recent years. It is important to develop rapid and accurate methods to determine ketamine and its metabolites in biological samples. The metabolites of ketamine are norketamine and dehydronorketamine in vivo. At present, there are blood, urine, hair and so on as specimens for detection, while the methods include GC, GC/MS, HPLC, LC/MS, HPCE etc. In this paper, these methods used for ketamine and its metabolites were reviewed in order to provide some preference for the study in relative fields.
Anesthetics, Dissociative/chemistry* ; Chromatography, High Pressure Liquid/methods* ; Forensic Medicine ; Gas Chromatography-Mass Spectrometry/methods* ; Hair/chemistry* ; Humans ; Ketamine/metabolism* ; Sensitivity and Specificity ; Substance Abuse Detection/methods*

OBJECTIVETo investigate the expression of protein kinase C (PKC) in the spinal dorsal horn of rats with formalin-induced pain and the effect of intrathecal ketamine on PKC expression.

METHODSThirty-two SD rats were randomly divided into 4 equal groups, namely the control group, intrathecal saline group (NS), 50 µg ketamine group (K1) and 100 µg ketamine group (K2). The rats were anesthetized with 10% chloral hydrate, and a microspinal catheter was inserted intrathecally into the lumbar region. Five days later, the rats in groups, K1 and K2 were subjected to intrathecal administration of 50 and 100 µg ketamine (10 µl), respectively, followed by 10 µl saline, and those in NS group received 20 µl saline only. Thirty minutes later, 5% formalin (50 µl) was subcutaneously injected into the left hindpaw. The pain intensity score (PIS) was utilized to assess antinociceptive behavior within 1 h after formalin injection. Twenty-four hours later, the left hindpaw thickness was measured and the expression of PKC in the spinal dorsal horn in the L5 segment was assayed using immunohistochemistry.

RESULTSCompared to group NS, groups K1 and K2 showed significantly decreased PIS (P<0.01) in the second phase of formalin-induced pain; 24 h later, the left hindpaw thickness of group NS increased obviously in comparison with that in the control group (P<0.01), whereas the thickness was significantly reduced in group K1 and K2 as compared to that in group NS (P<0.05). The number of immunoreactive cells and the immunohistochemical score of PKC in the spinal dorsal horn were significantly higher in group NS than in group C (P<0.01), but significantly lower in groups K1 and K2 than in group NS (P<0.05).

CONCLUSIONIntrathecal ketamine produces obvious antinociception against formalin-induced pain in rats and inhibits the enhanced PKC expression in the spinal dorsal horn in response to formalin-induced pain, suggesting the important role of PKC in nociceptive signal transmission and modulation in the spinal cord.

Animals ; Formaldehyde ; adverse effects ; Injections, Spinal ; Ketamine ; administration & dosage ; pharmacology ; Male ; Pain ; chemically induced ; metabolism ; Pain Measurement ; Posterior Horn Cells ; metabolism ; Protein Kinase C ; metabolism ; Rats ; Rats, Sprague-Dawley ; Spinal Cord ; drug effects ; metabolism

OBJECTIVE: The stability of ketamine in biological samples was studied under different storage temperature and time. METHODS: The rabbits were given intragastric administration of ketamine with a dose of 150 mg/kg and were sacrificed after 30 minutes. Blood, liver, kidney and brain of the rabbits were stored at room temperature (between 18 degrees C and 24 degrees C) and -20 degrees C. The specimens were analyzed at different times by GC-MS and GC-NPD. RESULTS: At -20 degrees C, the concentration of ketamine decreased in all of samples (P < 0.05) within 30 days. The concentration of ketamine increased in all of samples stored at room temperature after 5 days(P < 0.05). CONCLUSION The stability of ketamine in biological samples stored at -20 degrees C was better than that at room temperature. The samples suspected containing ketamine should be stored at -20 degrees C and should be tested as soon as possible.
Animals ; Brain/metabolism* ; Cryopreservation ; Disease Models, Animal ; Drug Stability ; Female ; Forensic Toxicology ; Gas Chromatography-Mass Spectrometry/methods* ; Hydrogen-Ion Concentration ; Ketamine/poisoning* ; Kidney/metabolism* ; Liver/metabolism* ; Male ; Rabbits ; Specimen Handling/methods* ; Temperature ; Time Factors