No abstract

The minimum alveolar concentration MAC of isoflurane was measured in rats chronically treated with WIN 55,212-2. Methods: The MAC of isoflurane was determined in 24 male rats from expiratory samples at time of tail clamping under the following conditions: without treatment MAC(ISO), in rats treated for 21 days with WIN 55,212-2 MAC(ISO + WIN55), and in rats 8 days after stopping treatment with WIN 55,212-2 (MACISO + WIN55 + 8D). Results: The MAC(ISO) was 1.32 ± 0.06. In the MAC(ISO + WIN55) group, the MAC increased to 1.69 ± 0.09 (28%, p-value ≤ (0.0001). Eight days after stopping treatment with WIN55, the MAC did not decrease significantly, 1.67 ± 0.07 (26%, p-value ≤ 0.0001). Conclusions: The administration of WIN 55,212-2 for 21 days increases the MAC of isoflurane in rats. This effect does not disappear 8 days after discontinuation of treatment with the synthetic cannabinoid.

The effects of morphine (MOR) and dexmedetomidine (DEX) on the MAC of isoflurane were measured in rats chronically treated with the synthetic cannabinoid WIN 55,212-2 (WIN55). Methods: The MAC of isoflurane was determined in 32 male rats from expiratory samples at the time of tail clamping. The effects of morphine (MAC(ISO+MOR)) and dexmedetomidine (MAC(ISO+DEX)) on the MAC of isoflurane in untreated rats and rats treated for 21 days with WIN 55,212-2 (MAC(ISO+WIN55+MOR)) and (MAC(ISO+WIN55+DEX)) were measured. Prior to the administration of morphine and dexmedetomidine, the MAC of the isoflurane was measured in both untreated rats (MAC(ISO)) and those treated with WIN 55,212-2 (MAC(ISO+WIN55)). Results: The minimum alveolar concentration was measured as 1.32 ± 0.06 in the MAC(ISO) group and 1.69 ± 0.09 in the MAC(ISO+WIN55) group. The MAC of the MAC(ISO+MOR) group was 0.97 ± 0.02 (26% less than the control group, MAC(ISO)). MAC was measured as 1.55 ± 0.08 in the MAC(ISO+WIN55+MOR) group (8% less than the MAC(ISO+WIN55) group), 0.68 ± 0.10 in the MAC(ISO+DEX) group (48% less than the control group, MAC(ISO)), and 0.67 ± 0.08 in the MAC(ISO+WIN55+DEX) group (60% less than the MAC(ISO+WIN55) group). Conclusions: The administration of WIN 55,212-2 for 21 days increases the MAC of isoflurane in rats. The sparing effect on isoflurane of morphine decreases in rats chronically treated with the synthetic cannabinoid, WIN 55,212-2. Dexmedetomidine increases its sparing effect on the minimum alveolar concentration of isoflurane in rats chronically treated with WIN 55,212-2.

Background: The isoflurane minimum alveolar concentration (MAC) was measured in rats chronically treated with WIN 55,212-2. Methods: The isoflurane MAC was determined in 24 male rats from the end expiratory samples at time of tail clamping under the following conditions: without treatment (MACISO), in rats treated for 21 days with WIN 55,212-2 (MACISO+WIN55) and other group 8 days after stopping treatment for 21 days with WIN 55,212-2 (MACISO+WIN55+8D). Results: The MACISO was 1.32 ± 0.06. In the MACISO+WIN55 group the MAC increase to 1.69 ± 0.09 (28%). After 8 days stopping treatment, MAC did not decrease significantly 1.67 ± 0.07 (26%). Conclusions: The administration for 21 days of WIN 55,212-2 increases the MAC of isoflurane in rats; this effect does not disappear after 8 days of discontinuing treatment with the synthetic cannabinoid.

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 (ISO)) and those treated with a cannabinoid (MAC (ISO + CANN)). The effects of morphine (MAC (ISO + MOR)) and dexmedetomidine (MAC (ISO + DEX)) on untreated rats and rats treated for 21 days with the cannabinoids (MAC (ISO + CANN + MOR)) and (MAC (ISO + CANN + DEX) were also studied. Results: MAC (ISO) was 1.32 ± 0.06, and MAC (ISO + CANN) was 1.69 ± 0.09. MAC (ISO + MOR) was 0.97 ± 0.02 (26% less than MAC (ISO)). MAC (ISO + CANN + MOR) was 1.55 ± 0.08 (8% less than MAC (ISO + CANN)), MAC (ISO + DEX) was 0.68 ± 0.10 (48% less than MAC (ISO)), and MAC (ISO + CANN + DEX) was 0.67 ± 0.08 (60% less than MAC (ISO + CANN)). 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.