Enduring changes in dopamine receptor cells of pups from drug administration to pregnant and nursing rats

A decrease in specific [3H]spiroperidol binding to rat caudate tissue and a parallel decrease in sensitivity to apomorphine in eliciting stereotyped behavior was observed in the offspring of rat mothers treated with either haloperidol or alpha-methyl-p-tyrosine-methyl ester during pregnancy. In contrast, evidence of increased dopamine-receptor sensitivity was observed in the pups if haloperidol was administered to their mothers postpartum during nursing rather than during pregnancy.     

Long-term treatment with lithium prevents the development of dopamine receptor supersensitivity

Long-term treatment of rats with haloperidol produced an increased sensitivity to the locomotor and stereotypic effect of apomorphine. This behavioral dopaminergic supersensitivity was accompanied by increased binding of [3H] spiroperidol in the striatum. Rats treated concurrently with lithium and haloperidol failed to develop both behavioral sensitivity to apomorphine and increased striatal dopamine receptor binding. The ability of lighium to prevent recurrent manicdepressive episodes may be related, in part, to its ability to stabilize dopaminergic receptor sensitivity.     

Copulation in castrated male rats following combined treatment with estradiol and dihydrotestosterone

Castrated male rats injected daily with 2 micrograms of estradiol benzoate (EB) combined with 200 micrograms of dihydrotestosterone propionate (DHTP) displayed masculine mating behavior which was indistinguishable from that of other castrates treated with 200 micrograms of testosterone propionate (TP). Significantly less copulation was seen in rats treated with either 4 micrograms of TP plus 200 micrograms of DHTP or 2 micrograms of EB. Mating in male rats may depend on the action of both estrogenic and 5alpha-dihydro metabolites of testosterone.     

Sexual behavior: normal male patterning in androgenized female rats

Female rats treated with testosterone as neonates and as adults exhibited a temporal patterning of male copulatory behavior identical to that of normal males, although such females displayed few intromission reflexes and almost no ejaculatory patterns. With prenatal, postnatal, and adult testosterone treatment, female rats displayed all the characteristic masculine responses and intervals, including the ultrasonic postejaculatory vocalization.     

D1 dopamine receptor activation required for postsynaptic expression of D2 agonist effects

D1 and D2 dopamine receptors exert synergistic effects on the firing rates of basal ganglia neurons and on the expression of stereotyped behavior in rats. Moreover, the ability of D2 agonists to induce changes in basal ganglia single unit activity and spontaneous motor activity is dependent upon the presence of endogenous dopamine to stimulate D1 receptors; in rats treated with alpha-methyl-rho-tyrosine to reduce endogenous dopamine levels, the neurophysiological and behavioral effects of the D2 agonist quinpirole are significantly attenuated, while the effects of nonselective agonists like apomorphine, which stimulate both D1 and D2 receptors, or combinations of a D2 agonist and a D1 agonist are not attenuated. Thus, the previously held view that D2 receptors alone are responsible for evoking the changes in behavior and basal ganglia output induced by nonselective dopamine agonists and endogenous dopamine is not supported by these results, which indicate that these phenomena require concurrent stimulation of both dopamine receptor subtypes.     

Adenosine 3',5'-monophosphate content in rat caudate nucleus: demonstration of dopaminergic and adrenergic receptors

Dopamine, apomorphine, isoproterenol, and norepinephrine each increased the concentration of adenosine 3',5'-monophosphate in slice of rat caudate nucleus. The concentrations of dopamine, apomorphine isoproterenol, and norepinephrine causing half-maximal increases were 60, 150, 0.03 and 30 micromoles per liter, respectively. The effect of dopamine was blocked by fluphenazine, a dopamine receptor antagonist, but not by propranolol, a beta-andrenergic receptor antagonist. Conversely, the effect of isoproterenol was blocked by propranolol but not by fluphenazine. The results suggest that in rat caudate nucleus there are two distinct catecholamine receptors capable of causing increased concentrations of adenosine 3',5'-monophosphate, one having the characteristic of dopamine receptor, and the other having the characteristics of beta-adrenergic receptor.     

Mice: fighting by neonatally androgenized females

Administration of testosterone propionate to female mice on the day of birth resulted in increased fighting after administration of testosterone during adulthood. This fighting, comparable to fighting among normal male mice, suggests that early androgenic stimulation organizes neural structures mediating aggression in the mouse.     

鸡性分化前抑制雌激素合成对性行为和视前内侧核的影响

 在受精蛋孵化第3天从气室注入100 μl生理盐水或芳香化酶抑制剂(AI),出雏后常规饲养到8月龄性成熟,观察其性行为,检测血清性激素水平,观察下丘脑视前内侧核(POM)形态结构变化。结果发现,AI处理母鸡获得雄性交配行为,血中雌二醇(E2)和睾酮(T)含量发生变化,雄性交配频率与血清T/E2 比呈正相关。1日龄雌雄雏鸡POM细胞大小和形态无明显差异,AI处理后细胞均变大;性反转母鸡POM细胞形态较正常母鸡无明显变化,但细胞密度降低,细胞变小。结果表明,在胚胎期抑制芳香化酶活性可以引起血清性激素水平、性行为雄     

转基因抗矮花叶病玉米对大鼠生长发育的影响

为探讨转基因抗矮花叶病玉米对大鼠F2生长发育和雄性生殖器官结构的影响,将SD大鼠(F0)随机分为对照组和试验组,进行2代饲喂试验;统计F2仔鼠出生时平均体质量、出生存活率和哺育存活率,同时检测仔鼠早期各项生长发育指标,仔鼠饲喂至60 d处死,并对其睾丸及附睾进行组织学观察。结果表明,与对照组相比,食用含33%转基因抗矮花叶病玉米的SD大鼠,其F2仔鼠的平均体质量、成活率及早期各项发育指标达标率均无统计学差异,雄鼠睾丸和附睾组织无明显异常。因此,中长期饲喂33%转基因抗矮花叶病玉米,并未影响SD大鼠F2的生长发育和雄性生殖器官的组织结构。     

Rates of behavior and aging specified by mitochondrial function during development

To explore the role of mitochondrial activity in the aging process, we have lowered the activity of the electron transport chain and adenosine 5'-triphosphate (ATP) synthase with RNA interference (RNAi) in Caenorhabditis elegans. These perturbations reduced body size and behavioral rates and extended adult life-span. Restoring messenger RNA to near-normal levels during adulthood did not elevate ATP levels and did not correct any of these phenotypes. Conversely, inhibiting respiratory-chain components during adulthood only did not reset behavioral rates and did not affect life-span. Thus, the developing animal appears to contain a regulatory system that monitors mitochondrial activity early in life and, in response, establishes rates of respiration, behavior, and aging that persist during adulthood.     

孕期应激对绵羊子代表型编程效应研究进展

家畜孕期应激对子代行为、生理和神经方面有着复杂的影响,这种影响可以持续到子代成年甚至跨代遗传。家畜孕期管理不当会对母体产生应激,使母体及其子代的生长、健康和福利受损,从而影响家畜的经济价值。本文以绵羊孕期应激模型和人工合成糖皮质激素模拟应激模型的试验结果为切入点,系统总结了绵羊孕期应激对子代表型的影响,并讨论了研究结果异同的可能原因。研究发现,绵羊孕期应激可以影响子代出生体重、调节子代下丘脑—垂体—肾上腺轴发育、影响子代行为模式和认知能力、改变子代基因表达和大脑形态,并且母体糖皮质激素水平是决定子代表型变化的主要因素。未来研究方向应该侧重于绵羊孕期应激对子代基因表达、免疫功能、生产性能和母性行为的影响,以及不同妊娠时期母体应激的比较研究、对子代影响的连续研究和探讨孕期应激不良编程的应对策略研究。     

Maternally Inherited Sex Ratio in the Parasitoid Wasp Nasonia vitripennis

Facultative control of the sex ratio has been reported in the wasp Nasonia vitripennis. In a newly wild-eaught strain, females produced few or no male offspring and did not show the usual alterations of sex ratio in response to external conditions. The aberrant trait is inherited through females.     

麦蛾气味受体OrCo基因的克隆及其表达模式分析

为提高麦蛾茧蜂种群的室内扩繁效率,采用人为控制种蜂婚配条件,研究麦蛾茧蜂交配经历和种蜂性比对交配行为及子代性别分化的影响。结果表明:麦蛾茧蜂种蜂交配经历对雌雄交配行为具有显著影响。交配经历较少的雄蜂再行配对时,求偶次数和交配次数较多、求偶强度较强且单次交配时间较长。没有交配经历的雄蜂比有5~6次交配经历的雄蜂交配时间显著要长。麦蛾茧蜂雄蜂交配经历对子代雌雄性比具有一定影响,但对子代总蜂数量的影响不明显。较少交配经历的雄蜂与处女雌蜂交配繁育所获子代雌蜂数量较多,雌雄性比较高。室内人工繁殖时,适当提高麦蛾茧蜂种蜂中雄蜂的比例有助于提高子代雌蜂数,当种蜂性比为1雌3雄,益害比为2(雌蜂数)10时繁殖效率最佳。     

Hormone-induced sexual differentiation of brain and behavior in zebra finches

The male zebra finch sings, whereas the female does not. This behavioral dimorphism is correlated with the presence of morphological sex differences within the neural substrate that mediates this behavior, the song system. When a female chick is exposed to 17beta-estradiol her song system is subsequently masculinized. Either testosterone or 5alpha-dihydrotestosterone may then induce such a female to sing when an adult.     

Facilitation of brain self-stimulation by central administration of norepinephrine

Rats with electrodes implanted in the medial forebrain bundle stimulated their own brains at sharply reduced rates after systemic administration of disulfiram or intraventricular administration of diethyldithiocarbamate. Both drugs inhibit dopamine-beta-hydroxylase, the enzyme responsible for the final step in the biosynthesis of norepinephrine. The suppressed behavior was reinstated by intraventricular injections of 1-norepinephrine, but not by injection of its biologically inactive isomer, d-norepinephrine. Intraventricular administration of dopamine and serotonin did not restore self-stimulation. The rewarding effect of medial forebrain bundle stimulation may depend on the availability of norepinephrine as a transmitter, but not on dopamine or serotonin.     

Neonatal castration: influence on neural organization of sexual reflexes in male rats

Most male rats castrated 4 days after birth and given exogenous testosterone in adulthood were sexually motivated but incapable of completing the mating sequence with an ejaculatory response. When tested for sexual reflexes after spinal transection, these animals displayed impairment of genital responses. Similarly treated 12-day castrates exhibited a complete mating sequence and had normal sexual reflexes. Thus neonatal testicular androgen appears to have an organizational influence at the spinal level on neural tissue mediating sexual reflexes.     

寄主大小及寄生顺序对蝇蛹佣小蜂寄生策略的影响

寄主大小模型认为寄生蜂后代性比与寄主大小相关,寄生蜂倾向于在大寄主上产出更多雌性后代,在小寄主上产出更多雄性后代。探讨了以家蝇蛹为寄主时,蝇蛹佣小蜂后代产量和性比变化;单次寄生情况下,寄主大小及寄生顺序对寄生蜂后代性比等影响。结果表明,蝇蛹佣小蜂的产卵期为(8.93±3.34) d,单头雌蜂能产雌性后代(34.11±16.34)头和雄性后代(11.04±8.87)头,且雄性百分比为0.24±0.11。随成蜂日龄的增大,寄生蜂产生雄性后代的比率显著增加。蝇蛹佣小蜂在寄生家蝇蛹时,会优先选择寄生个体较大的蛹;在单次寄生的情况下,蝇蛹佣小蜂倾向于在较大的家蝇蛹内产出更多的雌性后代。     

BEHAVIOR OF ADULT RATS IS MODIFIED BY THE EXPERIENCES THEIR MOTHERS HAD AS INFANTS

Some rat pups were handled for 20 days in infancy, while others were not. When the rats reached adulthood the females were bred. Some of the offspring were left with their natural mothers, others were fostered to mothers of the same background (handled/nonhandled) as that of their natural mothers, while still others were fostered to mothers with a different background from that of their natural mothers. The offspring were weaned and weighed at 21 days; at 50 days, activity and defecation scores were obtained in the open field. The weights at weaning and the defecation scores at 50 days were significantly influenced by the experience in infancy of the "postnatal" mother, whether she was the natural mother or a foster mother. The natural mother and the foster mother jointly affected the open-field activity of the offspring.     

Pituitary gonadotrophs: nuclear concentration of radioactivity after injection of ( 3 H)testosterone

Gonadotrophs and castration cells in the male rat pituitary showed nuclear concentration of radioactivity 1 hour after [1,2,6,7-(3)H]testosterone injection. Thyrotrophs and acidophils did not retain radioactivity; also the cells of the intermediate and posterior lobes did not accumulate radioactivity. The autoradiographic results suggest a direct and selective action of androgen on gonadotrophs, which contrasts with the action of estradiol which was shown earlier to bind not only to basophils but to acidophils and chromophobes as well.     

Analysis of the Offspring Sex Ratio of Chicken by Using Molecular Sexing

The overall sex ratio of offspring （dead embryos and hatch chicks） from all the fertilized eggs of 140 hens collected for 30 days was studied using duplex PCR of certain fragments of sex chromosomes. Additional 894 dead embryos over a period of 21 days of incubation were also investigated to verify the sex ratio of the dead embryos. The sex of the early dead embryos was identified using this molecular sexing technique. The sex ratio of the hatch chicks and the total offspring of the hens investigated in this experiment did not differ from the expected sex ratio （i.e., 1：1）., However, the number of female dead embryos was significantly more than that of males. The data indicated that the different physiologic function of males and females contributed to female-biased mortality during incubation. It was also found by further analysis that the sex ratios of the offspring of some hens were significantly biased to female or male over the period investigated, which suggested that the sex ratio of offspring might be influenced by the maternal condition to some degrees.