Kratom is a medicinal plant that exhibits promising results as an opiate substitute. However, there is little information regarding the abuse profile of its main psychoactive constituent, mitragynine (MG), particularly in relapse to drug abuse. Using the place conditioning procedure as a model of relapse, this study aims to evaluate the ability of MG to induce conditioned place preference (CPP) reinstatement in rats. To evaluate the cross-reinstatement effects, MG and morphine were injected to rats that previously extinguished a morphine- or MG-induced CPP. Following a CPP acquisition induced by either MG (10 and 30 mg/kg, i.p.) or morphine (10 mg/kg, i.p.), rats were subjected to repeated CPP extinction sessions. A low dose priming injection of MG or morphine produced a reinstatement of the previously extinguished CPP. In the second experiment of this study, a priming injection of morphine (1, 3 and 10 mg/kg, i.p.) dose-dependently reinstated an MG-induced CPP. Likewise, a priming injection of MG (3, 10 and 30 mg/kg, i.p.) was able to dose-dependently reinstate a morphine-induced CPP. The present study demonstrates a cross-reinstatement effect between MG and morphine, thereby suggesting a similar interaction in their rewarding motivational properties. The findings from this study also suggesting that a priming exposure to kratom and an opioid may cause relapse for a previously abused drug.

Kratom 是一种药用植物，作为阿片类药物的替代品具有良好的效果。然而，关于其主要精神活性成分 mitragynine (MG) 的滥用概况的信息很少，特别是在药物滥用的复发中。使用位置调节程序作为复发模型，本研究旨在评估 MG 诱导大鼠条件性位置偏好 (CPP) 恢复的能力。为了评估交叉恢复效应，将 MG 和吗啡注射到先前熄灭吗啡或 MG 诱导的 CPP 的大鼠中。在由 MG（10 和 30 mg/kg，ip）或吗啡（10 mg/kg，ip）诱导的 CPP 采集后，对大鼠进行重复的 CPP 消退期。MG 或吗啡的低剂量启动注射可恢复先前熄灭的 CPP。在本研究的第二个实验中，吗啡 (1, 3 和 10 mg/kg, ip) 的引发注射剂量依赖性地恢复了 MG 诱导的 CPP。同样，MG (3, 10 和 30 mg/kg, ip) 的启动注射能够剂量依赖性地恢复吗啡诱导的 CPP。本研究证明了 MG 和吗啡之间的交叉恢复效应，从而表明它们的奖励激励特性存在类似的相互作用。这项研究的结果还表明，初次接触 kratom 和阿片类药物可能会导致以前滥用的药物复发。本研究证明了 MG 和吗啡之间的交叉恢复效应，从而表明它们的奖励激励特性存在类似的相互作用。这项研究的结果还表明，初次接触 kratom 和阿片类药物可能会导致以前滥用的药物复发。本研究证明了 MG 和吗啡之间的交叉恢复效应，从而表明它们的奖励激励特性存在类似的相互作用。这项研究的结果还表明，初次接触 kratom 和阿片类药物可能会导致以前滥用的药物复发。