| Summary: | The impacts of morphine and dexmedetomidine on the MAC of isoflurane were studied in rats constantly medicated with the cannabinoid WIN 55,212-2. Methods: Prior to the administration of morphine, the MAC was measured in both untreated rats (MAC <sub>(ISO)</sub>) and those treated with a cannabinoid (MAC <sub>(ISO + CANN)</sub>). The effects of morphine (MAC <sub>(ISO + MOR)</sub>) and dexmedetomidine (MAC <sub>(ISO + DEX)</sub>) on untreated rats and rats treated for 21 days with the cannabinoids (MAC <sub>(ISO + CANN + MOR)</sub>) and (MAC <sub>(ISO + CANN + DEX</sub>) were also studied. Results: MAC <sub>(ISO)</sub> was 1.32 ± 0.06, and MAC <sub>(ISO + CANN)</sub> was 1.69 ± 0.09. MAC <sub>(ISO + MOR)</sub> was 0.97 ± 0.02 (26% less than MAC <sub>(ISO)</sub>). MAC <sub>(ISO + CANN + MOR)</sub> was 1.55 ± 0.08 (8% less than MAC <sub>(ISO + CANN)</sub>), MAC <sub>(ISO + DEX)</sub> was 0.68 ± 0.10 (48% less than MAC <sub>(ISO)</sub>), and MAC <sub>(ISO + CANN + DEX)</sub> was 0.67 ± 0.08 (60% less than MAC <sub>(ISO + CANN)</sub>). Conclusions: Medication with a cannabinoid for 21 days augmented the MAC of isoflurane. The sparing effect of morphine on isoflurane is lower in rats constantly medicated with a cannabinoid. The sparing effect of dexmedetomidine on the minimum alveolar concentration of isoflurane is greater in rats repeatedly medicated with a cannabinoid.
|
|---|