Azad S C, Marsicano G, Eberlein I, Putzke J, Zieglgänsberger W, Spanagel R, Lutz B
Clinic for Anaesthesiology, Pain Treatment Unit, Ludwig-Maximilians-University, Munich, Germany.
Eur J Neurosci. 2001 Feb;13(3):561-8. doi: 10.1046/j.1460-9568.2001.01431.x.
This study investigated whether the nitric oxide pathway was involved in the central effects of Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the major psychoactive constituent of cannabis sativa. Body temperature, nociception and locomotion were measured in neuronal nitric oxide synthase (nNOS) knock-out (KO) mice and wild-type (WT) controls after intraperitoneal application of Delta(9)-THC. These Delta(9)-THC-induced effects are known to be mediated through the brain-type cannabinoid receptor 1 (CB1). Therefore, in situ hybridization (ISH) experiments were performed in the adult murine brain to determine possible changes in CB1 mRNA levels in nNOS-KO, compared with WT mice, and to reveal brain areas where CB1 and nNOS were coexpressed in the same neurons. We found that an intraperitoneal injection of 10 mg/kg Delta(9)-THC led to the same increase in the hot plate latencies in both genotypes, suggesting that Delta(9)-THC-mediated antinociception does not involve nNOS. In contrast, a significant Delta(9)-THC-induced decrease of body temperature and locomotor activity was only observed in WT, but not in nNOS-KO mice. ISH revealed significantly lower levels of CB1 mRNA in the ventromedial hypothalamus (VMH) and the caudate putamen (Cpu) of the nNOS-KO animals, compared with WT mice. Both areas are known to be among the regions involved in cannabinoid-induced thermoregulation and decrease of locomotion. A numerical evaluation of nNOS/CB1 coexpression showed that approximately half of the nNOS-positive cells in the dorsolateral Cpu also express low levels of CB1. ISH of adjacent serial sections with CB1 and nNOS, revealed expression of both transcripts in VMH, suggesting that numerous nNOS-positive cells of VMH coexpress CB1. Our findings indicate that the nitric oxide pathway is involved in some, but not all of the central effects of Delta(9)-THC.
本研究调查了一氧化氮途径是否参与了大麻的主要精神活性成分Δ⁹-四氢大麻酚（Δ⁹-THC）的中枢效应。在腹腔注射Δ⁹-THC后，对神经元型一氧化氮合酶（nNOS）基因敲除（KO）小鼠和野生型（WT）对照小鼠的体温、痛觉和运动进行了测量。已知这些由Δ⁹-THC诱导的效应是通过脑型大麻素受体1（CB1）介导的。因此，在成年小鼠脑中进行了原位杂交（ISH）实验，以确定与WT小鼠相比，nNOS-KO小鼠中CB1 mRNA水平的可能变化，并揭示CB1和nNOS在同一神经元中共表达的脑区。我们发现，腹腔注射10 mg/kg的Δ⁹-THC导致两种基因型的热板潜伏期有相同程度的增加，这表明Δ⁹-THC介导的抗痛觉作用不涉及nNOS。相反，仅在WT小鼠中观察到了由Δ⁹-THC引起的显著体温下降和运动活动减少，而在nNOS-KO小鼠中未观察到。ISH显示，与WT小鼠相比，nNOS-KO动物的腹内侧下丘脑（VMH）和尾状壳核（Cpu）中CB1 mRNA水平显著降低。已知这两个区域都参与了大麻素诱导的体温调节和运动减少。对nNOS/CB1共表达的数值评估表明，背外侧Cpu中约一半的nNOS阳性细胞也表达低水平的CB1。用CB1和nNOS对相邻连续切片进行ISH，显示VMH中两种转录本均有表达，这表明VMH中许多nNOS阳性细胞共表达CB1。我们的研究结果表明，一氧化氮途径参与了Δ⁹-THC的一些但并非全部中枢效应。
