Effect of the benzodiazepine receptor agonist,zolpidem, on palatable fluid consumption in the rat

Two experiments examined the effect of the benzodiazepine receptor agonist, zolpidem, on palatable fluid intake in water-deprived rats. In the first experiment, pretreatment with 3.0 or 10.0 mg/kg zolpidem IP was found to increase consumption of a novel glucose drink (3% d-glucose and 0.1% sodium saccharine w/v in water). The increase in fluid consumption induced with zolpidem was comparable to the increases observed with diazepam and the benzodiazepine partial agonist, FG 8205. Experiment 2 demonstrated that this zolpidem-induced increase in drinking could be observed in both naive rats and in rats that had been habituated to the glucose drink and the testing environment: pretreatment with 3.0 mg/kg PO of zolpidem was found to increase fluid consumption in rats that had received either 0 or 8 days pre-exposure to the testing conditions. Contrary to earlier reports, these results support the conclusion that zolpidem, like other benzodiazepine agonists, can directly modulate ingestive behaviour.     

8205对CaCl_2、NE和KCl诱发兔胸主动脉条收缩的影响

离体兔胸主动脉条标本,测定8205对CaCl_2、JE引起收缩的量—效曲线及对单剂量KCl所致收缩的影响。结果表明,8205能使CaCl_2和NE的量—效曲线右移,并使最大反应压低,呈非竞争性拮抗,IC_(50)分别为13μmol/L和51μmol/L。8205也能抑制高K~+(67.1mmol/L)引起肌条的收缩反应,其IC_(50)为35.4μmol/L。与已知钙拮抗剂Ver比较,8205对三种激动剂收缩肌条的抑制作用与Ver湘似,但较弱。     

人源汉坦病毒H8205株M基因序列分析及其分类地位的研究

目的 :测定汉坦病毒H82 0 5株M基因全序列并对其分类地位进行探讨。方法 :从感染H82 0 5株病毒的鼠脑中提取RNA ,经RT PCR扩增M基因全序列 ,克隆到 pGEM TEasy载体中测序 ,与汉坦病毒属的各型标准株进行同源比较 ,构建系统进化树 ,并与汉滩型中已知的 7株病毒进一步比较 ,确定H82 0 5株的分类地位。结果 :H82 0 5株M基因由 36 15个核苷酸组成 ,编码1135个氨基酸 ;同源性分析显示该株病毒属于布尼亚病毒科汉坦病毒属中的汉滩型 (HTN) ,但与同型中其他毒株的亲缘关系较远。结论 :H82 0 5株是不同于已知汉滩型毒株的一个新亚型 ,表明我国的汉滩型病毒存在不同亚型     

Effect of Corocinnarine on Physiological Characteristics of Guinea Pig Papillary Muscles

In our experiment it was found that,in guinea pig papillary muscles,8205 de-creased the automaticity and prolonged the functional refractory period(FRP)as well asdecreased the contractile amplitude dose-dependently,but exerted no effect on the excitabili-ty.The dose-response curves of isoproterenol shifted to the right in parallel manner,inaccordance with competitive antagonistic,but the effect of 8205 was much less than thatof propranolol.Dose-response curves of CaCl_2 shifted to the right non-parallelly.The re-sults indicated that the mechanism of anti-arrhythmia of 8205 might be related to theCa~(2+)-antagonism.     

冠脑益嗪对豚鼠乳头肌生理特性的影响

冠脑益嗪(8205)可抑制豚鼠乳头状肌的收缩力,能降低其自律性,延长其不应期,而对兴奋性无明显影响。普诺洛尔和较大剂量的8205,均可使异丙肾上腺素的量-效曲线平行右移,符合竞争性拮抗剂的特点,唯8205的作用远弱于普诺洛尔;维拉帕米与8205,均可使CaCl_2的量-效曲线右移,且其最大收缩幅度,均有明显降低,呈非竞争性拮抗。     

State-dependent effects of atypical benzodiazepine-receptor agonists

The state-dependent effect of the BZ-receptor agonist diazepam (1.25–10 mg/kg), the partial agonist FG 8205 (0.5–4.0 mg/kg) and the BZ₁-receptor agonist zolpidem (0.25–2 mg/kg) were investigated in rats. During daily sessions, animals were trained to acquire FR10 lever pressing for food reinforcement whilst under the influence of the agonists, using an operant technique. Forty-eight hours after the final training session under drug, their performance of the FR10 was evaluated during a test session, carried out following vehicle administration only. Neither diazepam, nor FG 8205 impaired acquisition of the task. In the group treated with 2 mg/kg zolpidem, six out of eight rats failed to learn within 20 sessions, but the smaller doses were without effect on acquisition. When drug treatment was withdrawn, there was evidence that all three of the agonists tested produced state-dependency. This was apparent in the form of longer latencies to obtain reinforcement and decreased lever pressing rates. The significance of these findings are discussed in the context of the relationship between the state-dependent effects of BZ-receptor agonists and their other properties, and the receptor subtypes which might underly these effects.