Effects of intranasal zinc sulfate on open field and maternal behavior in female rats

Nulliparous white rats were injected intranasally (IN) or intraperitoneally (IP) with zinc sulfate (Zn) or were injected IN with saline or air, and were induced to show maternal behavior through continuous pup exposure begun 24 or 48 hr after treatment. ZnIN and ZnIP groups all showed declines in locomotor activity and rearing in an open field. ZnIN females sniffed less and groomed more often and for more total time than ZnIP or AIR females, effects attributed to nasal irritation and impaired olfaction. Declines in activity did not appear due to systemic absorption of zinc sulfate. Induction of maternal behavior was facilitated by ZnIN but not by ZnIP. Modifications of IN injection procedures were felt to have reduced post-treatment debilitation caused by accidental aspiration of zinc sulfate.     

Gastroprotective effect of zinc sulfate in ethanol-induced ulcerogenesis in rats

In a rat model of ethanol-induced peptic ulcer it is demonstrated that pretreatment with zinc sulfate (intragastral administration) lowers the ethanol-induced damage to the gastral mucosa in a dose-dependent manner. Subcutaneous injection of indomethacin has no appreciable effect on the gastroprotective effect of zinc. It is assumed that the gastroprotective effect of zinc sulfate is not mediated by the release of endogenous prostaglandins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 49–50, January, 1995 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Effects of prenatal nutrition on learning and motivation in rats.

The results of two learning experiments revealed that adult male rats whose dams suffered either prenatal zinc deficiency or undernutrition showed, as compared to rats whose dams were fed ad lib, normal diets during pregnancy (1) more resistance to extinction following partial reinforcement, and (2) a faster occurring negative contrast effect when shifted from large to small reward. An incentive-motivation interpretation of the data suggests that the nutritionally deprived and normal animals differ with respect to the incentive value of the consummatory reward. This effect appears to be long-term.     

硒酸锌金属自显影技术检测游离锌离子在小鼠肾脏的分布

目的研究游离锌离子在小鼠肾脏的定位分布。方法应用硒酸锌金属自显影技术(ZnSeAMG)检测小鼠肾脏内的游离锌离子分布。结果游离锌离子在肾脏内分布广泛,皮质中有大量AMG反应阳性颗粒,髓质中的AMG阳性颗粒较少。其中,近曲小管、远曲小管、近直小管和远直小管上皮细胞近腔侧均分布有大量的棕黑色AMG阳性颗粒,肾小体、细段和集合管上皮细胞中AMG阳性颗粒较少。结论小鼠肾脏内含有丰富的游离锌离子,锌离子可能参与肾脏的功能。     

Intravenous immunoglobulin (IVIG) treatment of experimental colitis induced by dextran sulfate sodium in rats

We investigated the therapeutic effect and immunological action mechanism of IgG in experimental colitis induced by 3% dextran sulfate sodium in rats. Intravenous injection of homologous (rat) IgG (400 mg/kg per day) caused a significant suppression of occult blood discharge and ulcerative lesions in the colon, while no suppressive effect was observed in the case of heterologous (human) IgG. The positive effect of rat IgG on the lesions was also clearly shown by the histological examinations. Generation of proinflammatory cytokines, i.e. tumour necrosis factor-alpha (TNF-α) and IL-1α, in the lesions was found to be inhibited by administration of rat IgG. Little or no suppressive action was exerted by human IgG. Careful examination of recruited T cells and macrophages, both of which are thought to play important roles in the development of ulcerative colitis, indicated that rat IgG, but not its human counterpart, decreased the number of immunocompetent cells in colonic mucosa. Meanwhile, in an in vitro study, both forms of IgG were shown to suppress production of TNF-α and IL-1α from lamina propria mononuclear cells isolated from rat colon. These findings suggest that, mainly by suppressing recruitment of immunocompetent cells into the lesions, homologous IgG may reduce the occurrence of colitis.     

Midbrain lesions eliminate sexual receptivity but spare sexual motivation in female rats

To measure sexual motivation we have used a preference test paradigm which involves testing a female with a sexually active male and a sexually inactive castrate male at the same time. On the assumption that a sexually motivated female will choose to spend more time with a partner who can provide her with stimulation appropriate to her motivational state, a female can be said to be sexually motivated to the extent that she spends more time with the active male than with the castrate. We find that bilateral destruction of the midbrain peripeduncular region eliminates the lordosis reflex in female rats, and abolishes sexual soliciting darting responses. Lesioned females treated with ovarian hormones continue, however, to show a strong preference for a sexually active male over a castrate. Thus, although peripeduncular destruction eliminates copulatory behavior, such destruction appears to spare hormone dependent systems for sexual motivation.     

Prolonged decrease in stress reactivity caused by dehydroepiandrosterone sulfate

In male rats exposed to repeated stress, the decrease in stress reactivity produced by subcutaneous injection of dehydroepiandrosterone sulfate (recorded by the decrease in stress-induced concentrations of corticosterone and adrenocorticotropic hormone in blood plasma) was observed 1–6 days postinjection and involved central regulatory mechanisms. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 141, No. 5, pp. 507–510, May, 2006     

硫酸镁预防瑞芬太尼术后痛觉过敏

目的观察术中静脉注射硫酸镁预防瑞芬太尼麻醉患者术后痛觉过敏的效果。方法择期行腹腔镜胆囊切除术患者60例,随机分为硫酸镁治疗组（M组,n=30）和对照组（C组,n=30）。常规诱导插管后,以0.4μg·kg-1.min-1速率维持瑞芬太尼输注,调节七氟醚吸入浓度维持BIS至40~60之间。M组麻醉诱导后15 min内静脉注射硫酸镁50 mg/kg后以15 mg·kg-1.h-1速率维持输注至手术结束;C组输注等质量生理盐水。记录术后30 min、1 h、2 h、4 h、8 h、12 h、24 h VAS评分,测定患者术前1 d及术后2 h、24 h静脉血Mg2＋浓度;手术前1 d及术后24 h进行2 min步行测验（2MWT）。观察并记录患者恶心呕吐、镇静、低血压等不良反应发生率。结果与C组比较,M组患者术后2 h及以内VAS评分有统计学差异（P〈0.05）,术后4~24 hVAS评分差异无统计学意义（P〉0.05）。术后2 h,M组血浆中Mg2＋浓度较C组显著增加（P〈0.05）,术后24 h恢复正常。M组患者术后24 h 2MWT距离恢复较C组快（P〈0.05）,M组患者恶心呕吐发生率较C组显著降低（P〈0.05）。结论术中静脉注射硫酸镁可有效预防瑞芬太尼术后痛觉过敏,促进患者术后功能恢复且不增加不良反应。     

Testosterone is not required for the enhancement of sexual motivation by yohimbine

Yohimbine HCL (2 mg/kg, 20 min prior to testing) administration was followed by significant decreases in the latencies to initial mount, intromission and ejaculation in castrated male rats bearing 2 mm testosterone-containing Silastic capsules 51 days after castration. Further, yohimbine stimulated copulatory activity in castrated, nonhormone-treated male rats up to 91 days after castration. Finally, yohimbine induced mounting in intact, nonreceptive female rats. These observations indicate that testosterone is not required for the enhancement of sexual motivation by yohimbine and support the suggestion that alpha 2-adrenoceptors are involved in the modulation of sexual arousal.