Differential Neurochemical Responses of the Canine Striatum with Pentobarbital or Ketamine Anesthesia: A 3T Proton MRS Study

Although anesthetic agents are known to affect cerebral metabolism, pentobarbital and ketamine have been widely used for animal imaging studies. The purpose of this study is to evaluate alterations in striatum metabolites in dogs between anesthetized with pentobarbital and with ketamine in proton magnetic resonance spectroscopy (1H-MRS). 1H-MRS was performed to ten healthy adult beagle dogs (9-11 kg) at a field strength of 3 T in order to identify metabolic changes after pentobarbital or ketamine administration in the striatum in vivo. Ten dogs were divided into 2 groups as follows: 5 as the pentobarbital-administered group (P group) and 5 as the ketamine-administered group (K group). We found that levels of Glx of the P group was significantly lower than that of the K group (6.90 ± 0.99 (SD) vs 9.77 ± 1.14 in 5 dogs, p= 0.003). In addition, the P group also has lower levels of Cr (6.29 ± 0.44 vs 7.89 ± 0.91 in 5 dogs, p=0.009) and NAA (5.02 ± 0.65 vs 6.45 ± 1.13 in 5 dogs, p=0.041) compared to the K group. However, there were no significant difference between the P group and the K group in striatal levels of Cho and Ins (p>0.1). We demonstrated that MRS-measured metabolites in the specific regions of the brain can be influenced by anesthetic agents.