The GABA a agonist muscimol enhances locomotor activity, but does not alter the behavioural effects of CRH in juvenile spring chinook salmon (Oncorhynchus tshawytscha)†

The present study investigated the effects of manipulating the GABAergic system on locomotor activity in juvenile spring chinook salmon, Oncorhynchus tshawytscha. In addition, we evaluated whether the GABAergic system is important for mediating the behavioural effects of corticotropin-releasing hormone (CRH). An intracerebroventricular (ICV) injection of the GABA_a agonist muscimol caused an acute and dose dependent increase in locomotor activity in juvenile spring chinook salmon. ICV injections of the GABA_a antagonist bicuculline prevented the increase in activity when administered concurrently with muscimol. The GABA_b agonist baclofen had no effect on locomotor activity in this study. Furthermore, we found no evidence that the locomotor response to exogenous CRH was altered by the concurrent administration of muscimol or bicuculline. These results provide evidence to support the hypothesis that endogenous GABA within the central nervous system is involved in the control of locomotor activity in fish. The data also suggest that there is no interaction between the GABAergic system and CRH with regards to the control of locomotor activity in this species.     

Mechanism of action of insecticidal secondary metabolites of plant origin

Insect pest management is facing the economic and ecological challenge worldwide due to the human and environmental hazards caused by majority of the synthetic pesticide chemicals. Identification of novel effective insecticidal compounds is essential to combat increasing resistance rates. Botanicals containing active insecticidal phytochemicals appear to be promising to address some of these problems. Therefore, there is a continuous need to explore new active molecules with different mechanisms of action. Secondary metabolites present in plants apparently function as defense (toxic), which inhibits reproduction and other processes. The phytochemical biomolecules could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability. In this article, the current state of knowledge on phytochemical sources and insecticidal activity, their mechanism of action in insects, resistance, and promising advances made in phytochemical research are reviewed.     

比色法测定茶叶GABA含量的可行性研究

应用比色法、HPLC和氨基酸自动分析仪法同时测定了六大茶类共45个样品的GABA含量,结果表明,HPLC与氨基酸分析仪测定结果基本一致,比色法和HPLC法测定的普洱茶、红茶、白茶、黄茶的结果差异极显著(P0.01),应用比色法测得的普洱茶和黑茶中GABA含量比HPLC测定结果高,而其他茶类测定结果低,推测茶叶中含有化学物质(色素、氨基酸等)干扰比色法测定。目前比色法不能应用于茶叶GABA测定,需要进一步改进方法以排除如氨基酸、茶色素等的干扰。     

Effect of dietary supplementation with taurine, β-alanine andGABA on the growth of juvenile and fingerling Japanese flounder Paralichthysolivaceus

ABSTRACT:   Three diets supplemented with taurine, β-alanine andGABA and a control diet were fed to juvenile and fingerling Japaneseflounder to investigate the effects of the diets on growth and metabolicchanges of free amino acids in whole body and tissues. In experimentI, three diets supplemented with 1% each of taurine, β-alanineand GABA and a control diet were fed to juvenile Japanese flounderwith an initial mean body weight of 0.4 g for 4 weeks at20°C. In experiment II, the taurine-supplemented diet anda control diet were fed to fingerling Japanese flounder with an initialmean body weight of 15 g for 4 weeks at 20°C.Only supplementation of taurine in the diet of juvenile flounderimproved their growth performance in experiment I, but fingerlinggrowth performance of experiment II was not significantly relatedto taurine supplementation in the experimental diet. These resultssuggest that there is a greater requirement for taurine for thegrowth of juvenile Japanese flounder than fingerling Japanese flounder.     

The Effect of Ivermectin on Convulsions in Rats Produced by Lidocaine and Strychnine

Ivermectin is one of the most commonly used drugs in pharmacotherapy of parasitic diseases in domestic and wild animals caused by parasitic nematodes and arthropods. However, ivermectin and other avermectins very often produce side-effects in hosts. The most dominant clinical symptom of ivermectin toxicity in domestic and wild animals is CNS depression. In nematodes, the target site of ivermectin’s action is glutamate-gated chloride-channel receptor and GABA receptor. The depressive effect of ivermectin in mammals might include more than one mechanism; therefore, the anticonvulsive effect of ivermectin against convulsions caused by lidocaine and strychnine was evaluated. Ivermectin antagonized lidocaine- and strychnine-induced convulsions in rats, although these have different mechanisms. In the present study, the anticonvulsive ED₅₀ of ivermectin for lidocaine-induced convulsions was 2.44 mg/kg (95% CL 1.67 to 3.57 mg/kg), whereas for convulsions induced by strychnine it was higher at 4.25 mg/kg (95% CL 2.32 to 3.78 mg/kg). At the same time, both anticonvulsive doses are significantly lower then the observed LD₅₀ of ivermectin (18.20 mg/kg). Furthermore, flumazenil (0.1 and 0.2 mg/kg), an antagonist of benzodiazepine receptors, antagonizes just one part of these anticonvulsive effects of ivermectin. Our results show the significant anticonvulsive properties of ivermectin and support the findings that ivermectin in the CNS of mammals produces multiple inhibitory effects, probably through participation in the function of GABA-sensitive and GABA-insensitive chloride channels.     

日本血吸虫体γ－氨基丁酸的检测

用高压液相色谱技术（ＨＰＬＣ）和同位素示踪技术确认日本血吸虫体内含有谷氨酸（Ｇｌｕ）、γ－氨基丁酸（ＧＡＢＡ）和琥珀酸（ＳＡ）。ＧＡＢＡ的含量为１２．７０±３．２７μｇ／ｇ（以虫湿重计）。虫体具有摄取外源性ＧＡＢＡ的能力。虫体不能将３Ｈ－ＧＩＡ转化为３Ｈ－ＧＡＢＡ，也不能将３Ｈ－ＧＡＢＡ转化为３Ｈ－ＳＡ。初步表明：虫体内ＧＡＢＡ的合成和降解与哺乳动物体内由Ｇｌｕ→ＧＡＢＡ→ＳＡ的代谢过程不同。     

氨酪酸对离体蟾蜍心脏活动的影响

采用常规离体蟾蜍心脏灌流法 ,通过生理记录仪经张力换能器系统描记心脏活动 ,探讨氨酪酸(GABA)对离体蟾蜍心脏活动的影响 ;结果表明 ,GABA明显增强了蟾蜍离体心脏收缩和舒张活动 ,并在一定范围内存在剂量依赖性 ;GABAA 受体阻断剂印防己毒素和GABAB 受体激动剂巴氯酚对心脏的收缩和舒张均有抑制作用 ;GABA能够加强肾上腺素对离体蟾蜍心脏的增强作用 ,而逆转乙酰胆碱的抑制作用 ;在酚妥拉明存在的条件下 ,GABA的正性肌力作用受到抑制 ;而在普萘洛尔和阿托品分别存在的条件下 ,GABA能够逆转普萘洛尔对离体蟾蜍心脏的抑制作用 ,而加强阿托品对离体蟾蜍心脏的增强作用 ;以上这些药品对心率均无明显影响。GABA对离体蟾蜍心脏的增强作用是通过GABAA 受体正性肌力作用和GABAB 受体负性肌力作用共同调节的 ,在生理状态下 ,以GABAA 受体作用为主 ,GABA的正性肌力作用可能是通过肾上腺素能系统中的α1 受体介导来完成的 ,而与胆碱能系统可能无关     

糙米发芽工艺参数研究

[目的]优化糙米发芽工艺参数.[方法]以黑龙江省糙米为原料制备发芽糙米,通过单因素试验确定最佳的糙米浸泡温度、浸泡时间、发芽温度、发芽时间,紫外分光光度法快速测定确定糙米及发芽糙米中的γ-氨基丁酸和游离氨基酸的含量为指标,进行正交试验.[结果]试验表明,浸泡温度为30℃,浸泡时间为10 h,发芽温度为35 ℃,发芽时间为34 h,此条件下γ-氨基丁酸的积累量达最高.浸泡温度为35℃,浸泡时间为12 h,发芽温度为25 ℃,发芽时间为34 h,此条件游离氨基酸积累量达最高.[结论]研究可为进一步了解黑龙江省七台河糙米产品提供依据.     

γ–氨基丁酸对低氧胁迫下甜瓜幼苗氮代谢及矿质元素含量的影响

 以甜瓜‘西域1号’为材料,采用营养液水培方法,研究了低氧胁迫下外源γ–氨基丁酸（GABA）对幼苗根系无机氮代谢及矿质元素含量的影响。试验结果表明,低氧胁迫下甜瓜根系中硝酸还原酶（NR）、亚硝酸还原酶（NiR）活性显著提高,硝态氮（NO₃^--N）、亚硝态氮（NO₂^--N）、铵态氮（NH₄⁺-N）以及谷氨酸、氨基酸、总氮含量显著增加,而可溶性蛋白含量显著降低,同时K⁺、Ca²⁺、Mg²⁺、Zn含量显著降低,Mn、Fe、Cu含量大幅提高,根系生长受到严重抑制;低氧胁迫下添加外源GABA处理的甜瓜根系中NO₃^--N、NO₂^--N、NH₄⁺-N、谷氨酸、氨基酸、可溶性蛋白质、总氮、K⁺、Ca²⁺、Mg²⁺、Zn含量以及NR、NiR活性显著高于低氧胁迫处理,而Mn、Fe、Cu含量显著降低,缓解了低氧胁迫对根系生长的抑制;低氧胁迫下同时添加GABA和钨酸钠处理的根系NR活性显著降低,同时NiR活性和NO₃^--N、NH₄⁺-N、谷氨酸、氨基酸、可溶性蛋白质、总氮含量和根系干质量均显著降低。说明低氧胁迫下外源GABA可以通过诱导NR活性的提高促进硝酸盐的吸收和转化,通过提高K⁺、Ca²⁺、Mg²⁺、Zn的吸收和减少Mn、Fe、Cu的吸收,缓解低氧胁迫甜瓜根系的伤害。     

Localization of amino acids in germinated rice grain: Gamma-aminobutyric acid and essential amino acids production approach

Germinated rice is popularly consumed for its high gamma-aminobutyric acid (GABA) and bioactive compounds. Supporting information on how to germinate rice with high GABA content and essential amino acids is lacking. White and colored rough rice were germinated for 0, 24, 48, 72, 96, 120 and 144 h. GABA, GABA substrates and essential amino acids were also investigated using GC-MS and MALDI-MSI. GABA was more concentrated after germination and shifted into the coleoptile. High correlation was recorded between germination time and GABA (0.79–0.83, p ≤ 0.01) and glutamic acid (0.88–0.89, p ≤ 0.01). Highest rates of GABA and glutamic production were observed within 48 h of germination in both rice varieties (26.12 and 34.28 mg/100g) and reached maximum value at 96 h (31.36 and 38.75 mg/100g). Colored rice germination showed higher GABA, GABA substrates and deficient amino acids than white rice. GABA and essential amino acids drastically increased after germination, supporting the consumption of germinated rice as a functional food.