This study was performed to compare the effect of intratesticular (IT) injection of xylazine/ketamine combination for canine castration with those of intramuscular (IM) or intravenous (IV) injection. Xylazine and ketamine was administered simultaneously via intratesticularly (IT group), intramuscularly (IM group) or intravenously (IV group) at doses of 2 and 10 mg/kg, respectively. Pain response at the time of injection, mean induction time, mean arousal time, mean walking time and cardiopulmonary function during anesthesia were monitored after the xylazine and ketamine administration. In IV and IM groups, heart rates were significantly decreased 30 and 45 min after xylazine and ketamine administration, respectively (p < 0.05). Respiratory rates were significantly decreased in the IV group (p < 0.05). In the IT group, there was no significant changes in heart and respiratory rates. The occurrence of cardiac arrhythmias was less severe in IT group compared with those in IM and IV groups. The route of administration did not affect rectal temperature. Mean induction time was significantly (p < 0.05) longer in IT group than in IM and IV groups. On the contrary, mean arousal time and mean walking time were shortened in IT group. Clinical signs related to pain response at the time of injection and vomiting were less observed in IT group than in IM group, and head shaking was less shown in IT group than in IM and IV groups during recovery period. These results indicated that intratesticular injection of xylazine/ketamine for castration has several advantages such as less inhibition of cardiopulmonary function and fast recovery from anesthesia without severe complications, and would be an effective anesthetic method for castration in small animal practice.
Anesthesia, Intravenous/veterinary ; Anesthetics, Combined/adverse effects/*therapeutic use ; Anesthetics, Dissociative/adverse effects/*therapeutic use ; Animals ; Body Temperature/drug effects ; Castration/*veterinary ; Dogs ; Drug Administration Routes/veterinary ; Electrocardiography/drug effects/veterinary ; Heart Rate/drug effects ; Injections/veterinary ; Injections, Intramuscular/veterinary ; Ketamine/adverse effects/*therapeutic use ; Male ; Pain, Postoperative/prevention&control/veterinary ; Pulmonary Ventilation/drug effects ; Testis/*drug effects ; Vomiting/chemically induced/veterinary ; Xylazine/adverse effects/*therapeutic use

OBJECTIVE: To observe the effect of intrathecal injection of ketamine and clonidine for chronic constriction injury (CCI) in rats. METHODS: Thirty-two SD male rats weighing 220-280 g were anesthetized with intraperitoneal chloral hydrate 300 mg/kg. A catheter was implanted in the subarachnoid space at the lumbal region and CCI rat models were made successfully. On the 4th day after the surgery, the rats were randomly divided into 4 group: a control group,injecting 0.9%NS 20 microL intrathecally; a ketamine group, injecting ketamine 1 mg/kg(20 microL) intrathecally; a clonidine group (CL), injecting clonidine 20 microg/kg (20 microL) intrathecally; a combined ketamine and clonidine group, injecting ketamine 0.5mg/kg and clonidine 10 g/kg (20 microL) intrathecally, once a day for 1 week. BME-410A Plantar Analgesia Tester was used to measured pain threshold before the administration and 30 min after the administration. The rats were killed after the test was finished. And then we detected the nitric oxide synthase (NOS) activity and the NO production in the spinal cord. RESULTS: The combined injection of ketamine (0.5mg/kg)and clonidine(10 g/kg) produced significantly more potent analgesia than the injection of ketamine (1 mg/ kg) or clonidine (20 microg/ kg)alone. The NOS activity and the production of NO in the combined injection group were significantly lower than those of the single injection group (P<0.05). The weight of rats post-administration increased obviously in the 4 groups (P<0.05). CONCLUSION The combined injection of ketamine and clonidine can produce synergistic ab-irritation without obvious side effects.
Analgesics ; administration & dosage ; adverse effects ; therapeutic use ; Animals ; Clonidine ; administration & dosage ; adverse effects ; therapeutic use ; Drug Combinations ; Injections, Spinal ; Ketamine ; administration & dosage ; adverse effects ; therapeutic use ; Male ; Neuralgia ; drug therapy ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Rats ; Rats, Sprague-Dawley ; Spinal Cord ; drug effects ; metabolism

OBJECTIVE: To explore the correlation between signs similar to schizophrenia in mice after ketamine administration and the expressions of NRG1 and ErbB4 mRNA in order to explain the possible pathogenesis of schizophrenia. METHODS: Fifty KM mice were randomly divided into 5 groups which were administered intraperitoneally with saline, clozapine and different dosages ketamine. The ketamine groups were administered intraperitoneally with low dosage (25 mg/kg), middle dosage (50 mg/kg) and high dosage (100 mg/kg) one time every day for 7 days. After administration of 100 mg/kg ketamine for 7 days, the clozapine group was introgastrically administered 20 mg/kg with clozapine one time every day for 7 days. The pathological changes of hippocampus neurons were observed by HE stain. The expressions of the NRG1 and ErbB4 mRNA in hippocampus were detected by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: In the group with high dosage of ketamine, the levels of NRG1 and ErbB4 mRNA were significantly lower than that of the group with saline. CONCLUSION Ketamine may induce signs similar to schizophrenia in KM mice. The mechanism may be involved in the reduction of NRG1 and ErbB4 mRNA expression.
Animals ; Clozapine/therapeutic use* ; Disease Models, Animal ; Dose-Response Relationship, Drug ; ErbB Receptors/metabolism* ; Hippocampus/pathology* ; Ketamine/adverse effects* ; Male ; Mice ; Neuregulin-1/metabolism* ; Neurons/metabolism* ; RNA, Messenger/metabolism* ; Random Allocation ; Receptor, ErbB-4 ; Reverse Transcriptase Polymerase Chain Reaction ; Schizophrenia/genetics*