Possible Interaction: Cannabinoids and Morphine

“The relative effectiveness of the cannabinoids in inhibiting morphine abstinence appeared to be in the following order: Δ9-tetrahydrocannabinol > Δ8-tetrahydrocannabinol > 11-hydroxy-Δ8-tetrahydrocannabinol > cannabidiol > cannabinol.”

“Two additional signs of morphine abstinence, defecation and rearing behavior, were also suppressed by the cannabinoids.”

“Although cannabinoids can modulate different stages of morphine encounter such as the reinstatement of morphine‐induced conditioned place preference (CPP), there is no evidence for the NAc neurons' response to prove it.”

“Our previous research has showed that nonanalgetic dose of a cannabinoid type 2 (CB2) receptor agonist reduced morphine tolerance in cancer pain.”

“Our findings suggest that cannabinoid CB1 receptors in the BLA are involved in the development of reward-related behaviors and they can potentiate the rewarding effects of morphine.”

“The results suggest that sub-chronic morphine treatment may produced sensitization to cannabinoids , which in turn reversed the impairment of spatial memory acquisition induced by WIN55,212-2 and mu- opioid receptors may play an important role in this effect.”

“These observations provide evidence that cannabinoid CB1 receptors in the NAc are involved in development of reward-related behaviors and they can potentiate the rewarding effects of morphine.”

“In fact, cannabinoid pretreatment enhanced the antinociceptive effect of microinjecting morphine into the ventrolateral PAG.”

“Experiments were conducted to test the hypothesis that topical cannabinoids would enhance the topical antinociceptive effects of morphine.”

“Here we show that a brainstem circuit that contributes to the pain-suppressing effects of morphine is also required for the analgesic effects of cannabinoids.”

“Changes in [Ca++]i and cAMP were evaluated as possible mechanisms by which the cannabinoids enhance the antinociception of morphine.”