• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.71-80
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• 1993

The central nervous system depressant effect of xylazine and xylazine-ketamine was studied in chicken and mice. Intraperitoneal injection of xylazine(1~30 mg/kg) and xylazine(1~30 mg/kg)-ketamine(100 mg/kg) induced a loss of the righting reflex in chicken and mice, respectively. These effects of xylazine were dose-dependent. The results obtained were as follows; 1. The effect of xylazine-induced depression was antagonized by adrenergic antagonists having ${\alpha}_2$-blocking activity(yohimbine, tolazoline, piperoxan and phentolamine). 2. Yohimbine was most effective in the reduction of the CNS depression by xylazine. 3. Phenoxybenzamine and prazosin did not reduced CNS depression by xylazine in both species. 4. Labetalol (${\alpha}_1$, ${\beta}_1$-adrenergic antagonist) and propranolol(${\beta}$-adrenergic blocking agent) were not effective in reducing xylazine induced depression. 5. Cholinergic blocking agents (atropine and mecamylamine), a dopaminergic antagonist (Haloperidol), a histamine $H_1$-antagonist(chlorpheniramine), a histamine $H_2$-antagonist(cimetidine), a serotonergic-histamine $H_1$ antagonist(cyproheptadine) were not effective in reducing xylazine-induced depression. 6. Xylazine-induced depression is mediated by ${\alpha}_2$-adrenergic receptors and appears not to be involved in cholinergic, dopaminergic, serotonergic or histaminergic pathways.

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.277-281
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• 1990

Xylazine is commonly used for anesthesia in veterinary medicine and various adverse effects are developed. To examine if the severe hypotensive response associated with xylazine-induced anesthesia might be resulted from the stimulation of presynaptic alpha-2 adrenoceptors or the increase of vagal tone, effects of yohimbine, atropine and atropine with vagotomy on xylazine-induced severe and long-lasting hypotensive responses were investigated in rabbits. The results were summarized as follows: 1) Intravenously injected xylazine(1mg/kg)-induced hypotensive responses were inhibited by yohimbine(p<0.001). 2) Intravenously injected xylazine(1mg/kg)-induced hypotensive responses were not changed by atropine. 3) Intravenously administered xylazine(1mg/kg)-induced hypotensive responses are not changed by atropine with vagotomy. These results indicate that xylazine is thought to cause severe hypotensive response during anesthesia primarily by stimulating presynaptic alpha-2 adrenoceptors and other receptors or mechanisms may participate in the hgpotensive response of xylazine.

• Journal of Veterinary Clinics
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• v.5 no.1
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• pp.37-42
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• 1988

The effect of yohimbine HCI(0.25mg / kg) on xylazine(0.15mg /kg) induced depression of rumen motility was investigated by means of electromyography of luminal wall in korean native goats. Yohimbine was administrated 5 min pre-xylazine injection, 5 min and 15 min after xylazine injection. The duration of lumen motility in cases of xylazine alone administration, yohimbine administration 5 min pre-xylazine injection, 5 min post-xylazine, and 15 min post-xylazine was 47-64, 36-40, 28-29, and 15-17 min, respectively. It is demonstrated that lumen contractions were inhibited by xylazine and the inhibition was most rapidly reversed by the administration of yohimbine 15 min after xylazine injection in which goat was completely sedated.

• Toxicological Research
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• v.9 no.2
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• pp.147-152
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• 1993

Xylazine has been used as tranquilizer for food producing animals. The concentration of xylazine and its metabolites in major organs are determined for the safety of meat. Xylazine was eliminated very rapidly as reported and not detected after 10 hrs in organs. However p-hydroxy-xylazine, a main metabolite of xylazine in urine, was detected in liver in the concentration of 0.37-2.58 mg/g tissue to 48 hrs. 2, 6-Dimethylisothiocyanate, another metabolite of xylazine and a possible toxicant, was detected in low concentration to 2 hrs in liver, kidney and muscle.

• Journal of Veterinary Clinics
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• v.9 no.1
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• pp.301-309
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• 1992

The present study was carried out to compare xylazine(2.2mg/kg, IV), xylazine/acepromazine(1.1mg/kg. IV : 0.2mg/kg, IV) and xylazine/diazepam(1.1mg/kg, IV :1.0mg/kg, IV) anesthesia, to determine useful method out of three kinds of anesthesia and tr evaluate this selected method at hypovolemic state. In xylazine, kylazine/acepromazine and kylazine/diazepam anesthesia, the heart rate was increases after administration of atropine until 10minutes after administration of anesthetics and then decreased gradually in all types of anesthesia. The respiratory rate was decreased after administration of anesthetics in all types of anesthesia. The body temperature was rarely changed in xyiazine/acepromazine and xylazine/diazepam anesthesia, but decreased continuously in xylazine anesthesia. In xylazine and kylazine/acepromazine anesthesia the pedal and corneal reflex were not disappeared completely, but reactions to pin pricking were disappeared. In xylazine/diazepam anesthesia their reflex and reactions were disappeared together. The time from head-up to standing was shortest(32.00min) in kylazine/diazepam anesthesia in comparision with xylazine and kylazine/acepromazine anesthesia. In xylazine/diazepam anesthesia, the heart rates in hypovolemic dogs were decreased soon after administration of anesthetics but recovered immediately. The changes in systolic and diastolic blood pressure in hypovolemic dogs revealed similar trends to their changes in normal dogs after administration of anesthetics. It is considered that rylazine/diazepam anesthesia is one of the useful anesthetic methods in healthy dogs and also in hypovolemic dogs.

• Journal of Veterinary Clinics
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• v.6 no.1
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• pp.165-171
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• 1989

Antagonistic effects of yohimbine on xylazine and ketamine anesthesia in goats were studied. Xylazine or ketamine anesthesia alone was not antagonized by yohimbine, but the time for consciousness and recovery in xylazine and ketamine anesthetized goats were remarkably shortened by yohimbine. Reversal effect of yohimbine on the heart rate and body temperature which decreased following xylazine and ketamine was not observed and respiratory rate which increased after xylazine and ketamine was sligtly reduced by yohimbine.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.519-522
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• 1991

Pain reflex and anesthetic state in swine with xylazine epidural anesthesia were observed. In xylazine epidural anesthesia, dosages of 0.50mg/kg BW for analgesia of perineal region and 0.7550mg/kg for analgesia of low abdominal wall were required. Regional anesthesia was induced 5~20 min after epidural injection of xylazine and recovered 90~120 min after administration. The results indicated that xylazine as an epidural local anesthetic was useful in swine.

• Korean Journal of Veterinary Research
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• v.22 no.1
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• pp.85-89
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• 1982

Xylazine and ketamine hydrochloride were given intramusculary to 32 deers (sika deer 7, red deer 11, elk 6, pere david deer 3, and reindeer 5). Ketamine hydrochloride was injected 30 minutes after administration of xylazine. Sedative action of combined anesthesia of xylazine and ketamine hydrochloride was similar to the sedative effects of xylazine alone. The recovery from sedation of combined anesthesia was remarkably fast comparing with xylazine alone.

• Archives of Pharmacal Research
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• v.14 no.4
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• pp.346-351
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• 1991

The biotransformation of xylazine, a widly used animal tranquilizer, was investigated in rats. After administration of xylazine, the existence of 2,6-dimethylphenyl-isothiocyanate, 2,6-dimenthyl-4-hydroxy-aniline and p-hydroxy-xylazine in urine was confirmed by the comparison with chemically prepared standards in GC/MS. The main metabolite, p-hydroxy xylazine was excreted as conjugated form.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.683-688
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• 1992

This study was performed to investigate the reverse effects of Jen Chung electroacupuncture at 10 and 30 min after xylazine administration(0.1mg/kg) in goats. In the group of electroacupuncture at 30 min after xylazine administration, MAT and MWT were markedly shorter than in control and in 10 min after xylazine administration. The RR intervals were continuously increased in control and in the group of electroacupuncture at 10 min after xylazine administration, but in the group of electroacapuncture at 30 min after xylazine administration significantly reduced from about 45 min. The frequency(cps) of EEG was recovered to normal pattern after 90 min in the group of electroacupuncture at 30 min after xylazine administration, but considerably delayed in control and in the group of electroacupuncture at 10 min. Respiratory rates tended to be somewhat decreased and then gradually increased in all groups. In control, there were shown cycloapneustic respirations but no in the electroacupuncture groups. It was turned out to be that the electroacupuncture stimulation of Jen Chung at 30 min after xylazine administration was effective for the reverse of the xylazine analgesia.