Volkow N D, Gillespie H, Mullani N, Tancredi L, Grant C, Valentine A, Hollister L
Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Psychiatry Res. 1996 May 31;67(1):29-38. doi: 10.1016/0925-4927(96)02817-x.
Despite the widespread abuse of marijuana, knowledge about its effects in the human brain is limited. Brain glucose metabolism with and without delta 9 tetrahydrocannabinol (THC) (main psychoactive component of marijuana) was evaluated in eight normal subjects and eight chronic marijuana abusers with positron emission tomography. At baseline, marijuana abusers showed lower relative cerebellar metabolism than normal subjects. THC increased relative cerebellar metabolism in all subjects, but only abusers showed increases in orbitofrontal cortex, prefrontal cortex, and basal ganglia. Cerebellar metabolism during THC intoxication was significantly correlated with the subjective sense of intoxication. The decreased cerebellar metabolism in marijuana abusers at baseline could account for the motor deficits previously reported in these subjects. The activation of orbitofrontal cortex and basal ganglia by THC in the abusers but not in the normal subjects could underlie one of the mechanisms leading to the drive and the compulsion to self-administer the drug observed in addicted individuals.
尽管大麻被广泛滥用，但关于其对人脑影响的了解却很有限。通过正电子发射断层扫描技术，对8名正常受试者和8名慢性大麻滥用者在使用和未使用δ9四氢大麻酚（THC，大麻的主要精神活性成分）的情况下的脑葡萄糖代谢情况进行了评估。在基线时，大麻滥用者的小脑相对代谢水平低于正常受试者。THC使所有受试者的小脑相对代谢增加，但只有滥用者的眶额叶皮质、前额叶皮质和基底神经节出现代谢增加。THC中毒期间的小脑代谢与主观中毒感显著相关。大麻滥用者在基线时小脑代谢降低可能是此前报道的这些受试者运动功能缺陷的原因。THC在滥用者而非正常受试者中激活眶额叶皮质和基底神经节，这可能是导致成瘾个体出现自我给药冲动和强迫行为的机制之一。
