IMMOBILIZATION OF CAPTIVE PINE MARTENS (MARTES-MARTES) WITH MEDETOMIDINE-KETAMINE AND REVERSAL WITH ATIPAMEZOLE

Six captive pine martens (Martes martes) were immobilized with a combi nation of medetomidine hydrochloride (MED) and ketamine (KET) in three experiments (Experiment 1, July 1991; Experiment 2, November 1991; Ex periment 3, January 1992) to establish a dose range for field use and to assess potential seasonal influence on drug effects. The mean +/- S D i.m. doses (range) used in these three experiments were 0.19 +/- 0.0 3 (0.14-0.24) mg/kg MED + 9.3 +/- 1.5 (7.1-11.8) mg/kg KET, 0.17 +/- 0 .04 (0.14-0.24) mg/kg MED + 8.6 +/- 1.8 (7.1-11.8) mg/kg KET, and 0.15 +/- 0.01 (0.13-0.17) mg/kg MED + 7.6 +/- 0.8 (6.5-8.9) mg/kg KET, res pectively. These doses induced complete immobilization with good muscl e relaxation and loss of both the corneal and pedal withdrawal reflexe s in all animals. The induction times were 4.3 +/- 1.6 (2.0-6.0) min, 3.8 +/- 0.8 (3.0-5.0) min, and 4.5 +/- 1.9 (3.0-8.0) min, respectively . Side effects included hypothermia, bradycardia, and bradypnea, but a ll animals recovered completely without clinical complications. Blood samples were drawn from immobilized animals and sera were analyzed for 24 different measures (enzymes, metabolites, minerals, and electrolyt es). Hyperglycemia occurred in all animals, but there were no clinical ly important differences in serum chemistry values among the experimen ts. Forty minutes after administration of MED-KET, the animals in Expe riments 1 and 2 were given atipamezole hydrochloride (ATI) i.m. at fiv e times the MED dose. In Experiment 3, the animals received saline i.m . for comparison. Immobilization was rapidly reversed by ATI, and side effects such as muscle rigidity and incoordination were of short dura tion. The mean time from ATI injection to mobility in Experiments 1 an d 2 was 7.7 +/- 2.3 (4.8-10.0) min and 3.8 +/- 1.6 (2.0-5.8) min, resp ectively. The mean mobility time was 31.7 +/- 21.8 (11.0-59.0) min in the saline-treated animals, and recovery was accompanied by prolonged sedation, incoordination, and motor impairment. MED in combination wit h KET and reversed with ATI at a dose ratio of 5:1 relative to MED was a safe and effective immobilization protocol for captive pine martens .