77 The second experiment investigated the possible neuronal

The second experiment investigated the possible neuronal mechanism underlying the effect of acupuncture. The baseline level of methamphetamine consumption in each group was similar, as in the first experiment (Fig. 2A). Acupuncture at HT7 also significantly inhibited the methamphetamine self-administration behavior (Fig. 2B and C). However, these acupuncture effects were blocked by pretreatment with the selective GABAA receptor antagonist BIC or the selective GABAB receptor antagonist SCH. The infusion of methamphetamine, which was reduced by 16.85% of the control group, was restored to 126.54% by BIC and to 144.61% by SCH. When compared with the baseline level, the inhibition caused by acupuncture and the reversal produced by the antagonists showed the same pattern (Fig. 2D). These results demonstrate that the GABAA and GABAB receptor systems mediated the suppressive effect of acupuncture on methamphetamine self-administration. In the mesolimbic system, enhancement of the dopaminergic neurons projecting from VTA to the NAc underlies the reward effects of drugs of abuse [19]. Therefore, therapies to treat drug abuse focus on reducing the activity of dopaminergic neurons in the NAc. The administration of methamphetamine not only enhances the release of DA but also blocks the re-uptake of DA in the synapse [22]. Accordingly, the reinforcing effect of methamphetamine lasts longer, and this potency drives individuals to drug abuse. In contrast, GABAergic 77 in the VTA exert inhibitory control on dopaminergic neurons via activation of GABA receptors on these neurons and eventually inhibit DA release in the NAc. Based on this relationship, we investigated the possible neuronal involvement of the GABA receptor system in the effects of acupuncture at HT7; our results showed that BIC or SCH reversed the effects of acupuncture. Our results suggest that the suppressive effect of acupuncture at HT7 on methamphetamine self-administration behavior is mediated, at least in part, via the GABA receptor system. This parallels our results [13], [14], [29] showing that acupuncture suppresses the reinforcing effects of morphine via GABA receptors. Such behavioral data have been confirmed using immunohistochemistry. The reduction in c-Fos expression in the NAc caused by acupuncture was blocked by BIC or SCH (Fig. 3). These results suggest that the enhanced dopaminergic neuron activity in the NAc by methamphetamine self-administration was attenuated by acupuncture, and this attenuation was reversed by BIC or SCH. In this study, the BIC- and SCH-alone groups were designed to examine the influence of GABAA and GABAB receptor antagonists, respectively, on methamphetamine self-administration behavior. The results revealed that either antagonist resulted in no significant difference from the control group, indicating that neither GABA receptor antagonist produced significant influence on the methamphetamine self-administration behavior. On the other hand, muscimol, the GABAA receptor agonist, and baclofen, the GABAB receptor agonist have shown to reduce the reinstatement as well as intake behavior in the intravenous self-administration of methamphetamine [18], [24], [25] implying that activation of GABA receptors attenuated DA neuron’s activity. The results of GABA agonists are similar with the acupuncture effect in this study. Therefore, it seems that acupuncture at HT7 acts as GABA agonist in methamphetamine self-administration.
Introduction The striped stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae) is a serious pest in rice and other crops, and is widely distributed in many countries of Asia, Europe, Oceania and Africa (Sheng et al., 2003). In China, C. suppressalis causes huge damage and economic losses to agricultural production, especially to rice production (Gu, 2018; Gong et al., 2017). The effective management strategy for C. suppressalis is mainly dependent on chemical control via massive use of insecticides, which has led to serious environmental pollution and high-level resistance of insect pests to insecticides in field populations. For example, a recent investigation found that C. suppressalis populations from Yuzhao and Cangnan in Zhejiang province of China have developed high-level (135.0–141.1 folds) resistance to chlorantraniliprole, which has been the most effective insecticide for the control of lepidopteran pests in recent years (Zhao et al., 2017).