Thermal antinociceptive, sedative and cardiovascular effects of Governing Vessel 1 dexmedetomidine pharmacopuncture in healthy cats

Objective: To compare the antinociceptive, sedative and cardiovascular effects of dexmedetomidine pharmacopuncture at Governing Vessel 1 (GV 1) with dexmedetomidine intramuscular (IM) administration. Study design: Randomized, masked crossover design. Animals: A group of eight healthy female cats. Methods: Cats were randomly administered either dexmedetomidine (0.005 mg kg^–1; Dex–IM) IM or at acupuncture point GV 1 (Dex–P) separated by 1 week. Prior to and up to 120 minutes posttreatment, skin temperature (ST), thermal threshold (TT), heart rate (HR), respiratory rate (f_R), sedation, muscle relaxation and auditory response scores were recorded. Parametric data were analyzed using a two-way repeated measures ANOVA followed by Tukey's test for multiple comparisons. Nonparametric data were analyzed using a Friedman test followed by Dunn's multiple comparisons test, and Wilcoxon signed-rank test with Bonferroni correction for multiple comparisons. Significance was set at p ≤ 0.05. Results: There were no differences within or between treatments for ST, f_R and auditory response. TT was significantly higher at 30–90 minutes in Dex–P (p ≤ 0.0285) than baseline. TT was significantly higher at 60–90 minutes for Dex–P than for Dex–IM (p ≤ 0.0252). HR was significantly lower at 10–75 minutes in Dex–P (p ≤ 0.0378) and at 5–75 minutes in Dex–IM (p ≤ 0.0132) than baseline. Compared with baseline, sedation scores were higher at 25 minutes (p = 0.0327) and 30 minutes (p = 0.0327), and muscle relaxation scores were higher at 25 minutes (p = 0.0151) and 35 minutes (p = 0.0151) in Dex–P. There were no differences in HR, sedation and muscle relaxation scores between treatments. Conclusions and clinical relevance: Dex–P increased thermal antinociception compared with Dex–IM at the same dose of dexmedetomidine in cats. This antinociceptive effect must be evaluated under clinical situations.