An experiment was carried out to examine the effect of yohimbine on xylazine-induced sedation and hyperglycemia in cattle. Group I were given alone xylazine (0.1 mg/kg IV : control) . Group II and III were given yohimbine (0.5 mg/kg IV) -α₂-adrenergic blocking agent, 30 minutes (II) and 10 minutes (III) after xylazine (0.1 mg/kg IV) . Group IV and V were given xylazine (IV; 0.1 mg/kg, V ; 0.05 mg/kg IV) immediately after yohimbine (0.5 mg/kg IV) .
Yohimbine (group II to V) did not antagonized the sedative effect with xylazine (group I) . The pretreatment with yohimbine (group IV, V) reduced or abolished xylazine-induced hyperglycemia and hypoinsulinemia (group I) .
The present study suggests that yohimbine alone can not be applied to cattle practice as antagonist of xylazine and xylazine-induced hyperglycemia and hypoinsulinemia are mediated by α₂-adrenergic receptors.

View full abstract

In 1983, the author described the experimental report on antagonism of xylazine and ketamine combination anesthesia by 4-aminopyridine (4-AP) and yohimbine (YO) in dogs, concluding that these antagonists are safe, fast-acting and specific in xylazine and ketamine combination anesthesia.
In this paper are described clinical applications to minor surgery in dogs.
Twenty cases selected for the need of reduction of awakening time were divided into 3 groups.
After beeing atropinized, all dogs were administrated xylazine subcutaneously (3 mg/ kg) and ketamine intramuscularly (5 mg/kg, 10 mg/kg) . Then, at the stage of surgical anesthesia, minor surgeries were done.
In group I, in which the operation time was less than 25 minutes were given 4-AP (0.3 mg/kg) and YO (0.125 mg/kg) intravenously.
In group II, in which the operation time was more than 30 minutes were given [4-AP (0.3 mg/kg) +YO (0.125 mg/kg) ] × _??_ intravenously.
In group III, in which the operation timee was less than 25 minutes were given 4-AP (0.3 mg/kg) and YO (0.125 mg/kg) intramuscularly.
In group I, the mean initial response time (RT; time from administration of combination of 4-AP and YO to cognition and ability to lift up head) was 2.3 min (control in the experiment ; 47.6 mm) . Mean alert time (AT; time to cognition and ability to wake up) was 3.8 min (control ; 53.0 mm) . Mean stand-up time (ST; time to cognition and ability to stand-up) was 6.3 min (control ; 60.0 mm) . And mean walk time (WT; time to cognition and ability to walk) was 10.8 min (control ; 65.4 mm) .
In group II, mean RT was 3.1 min. Mean AT, ST and WT were 4. 1, 7.2 and 11.8 min.
In group III, mean RT was 15.5 min. Mean AT, ST and WT were 18. 0, 22.2 and 27.0 min.
In all cases, loss of appetite, cherless or no good general conditions were not marked after operation. And abnormal hemorhage or delay of healing were not observed. Relapses to unconciousness did not occur.
Result of this study shows that in group I, the same effects were seen as the experimental groups previous by reported.
In group II, the same effects were also seen as in group I and the experimental groups. Therefore, if it takes over 30 min in operation, these antagonists may be reduced to _??_
In group III (the intramuscular administration) the time was delayed a little at RT, AT, ST and WT, in comparison with group I, II and the experimental groups (the intravenous administration) ; but effects were obvious in comparison with the control of the experimental groups.
The intramuscular administration may have some clinical significances when so fast awakening is not needed.

View full abstract

Anesthesia was introduced with sodium thiopental and maintained with halothane in cats and dogs. Comparative studies were made on these animals to clarify what extent irregular pulse (IP) was induced to in the routine clinical practice, when IP appeared in the period of anesthesia, how long IP continued, and the type and cause of occurrence of IP.
Irregular pulse in the period of anesthesia, except tachycardia induced by sodium thiopental, was found in 71 of 886 cats (8.0%) and 20 of 652 dogs (3.1%) . Therefore, the rate of occurrence of IP was higher in the cats than in the dogs.
The types of IP induced in the period of anesthesia were various, including upper ventricular early beat, ventricular early beat, multiple ventricular heterotopic beat, atrioventricular block of the first, second, and third degree, atrioventricular dissociation, atrial standstill, alternating pulse, sinus bradycardia, and sinus standstill.
The type of IP of frequent occurrence was ventricular early bea t in the dogs and multiple ventricular heterotopic beat in the cats. It was induced by the drug in nearly half of all the cases 10 minutes after the introduction of anesthesia. IP noticed in the maintenance of anesthesia was induced by artificial causes, such as visceral traction and ligation, in many cases. Animals showing IP during anesthesia extending from introduction to wakin were almost always suffering from the side effects of some auxiliary drugs, bad general conditions with serious anemia and hypothermia, and abnormality in serum electrolytes.
Particular attention had to be paid to IP which was accompanied with the extension of QT, sinus bradycardia, and the descent of ST.

View full abstract