Androgens prevent normally occurring cell death in a sexually dimorphic spinal nucleus

The spinal nucleus of the bulbocavernosus (SNB) contains many more motoneurons in adult male rats than in females. Androgens establish this sex difference during a critical perinatal period, which coincides with normally occurring cell death in the SNB region. Sex differences in SNB motoneuron number arise primarily because motoneuron loss is greater in females than in males during the early postnatal period. Perinatal androgen treatment in females attenuates cell death in the SNB region, reducing motoneuron loss to levels typical of males. The results suggest that steroid hormones determine sex differences in neuron number by regulating normally occurring cell death and that the timing of this cell death may therefore define critical periods for steroid effects on neuron number.     

Plasticity of motor behavior in monkeys with crossed forelimb nerves

Monkeys in which nerves innervating the flexor muscles of the forearm and hand (the ulnar or the median nerve) had been surgically cross-united with the nerve innervating the extensor muscles (the radial nerve), and vice versa, showed excellent (ulnar-radial crosses) to moderate (median-radial crosses) control of movement performance after regeneration. Antagonistic movement responses were seen occasionally, but these were corrected almost immediately. Stimulation of the crossed nerves showed that they had innervated the antagonistic muscle groups. The results reveal the capacity of the primate central nervous system to adapt to gross disturbances imposed on the execution of movements by changes in peripheral innervation.     

Androgens regulate the dendritic length of mammalian motoneurons in adulthood

Sex steroid hormones have been thought to alter behaviors in adulthood by changing the activity of neural circuits rather than by inducing major structural changes in these pathways. In a group of androgen-sensitive motoneurons that mediate male copulatory functions, decreases in androgen levels after castration of adult rats produced dramatic structural changes, decreasing both the dendritic length and soma size of these motoneurons. These changes were reversed by androgen replacement. These results imply a surprising degree of synaptic plasticity in adult motoneurons and suggest that normal changes in androgen levels in adulthood are associated with significant alterations in the structure and function of these neurons.     

雄激素对去势大鼠脊髓缘核AR蛋白表达的影响

用免疫组化SP法检测了去势及去势后补充雄激素大鼠脊髓灰质缘核中雄激素受体（Androgen receptors,AR）蛋白的表达情况,以探讨雄激素对缘核的作用。结果表明,睾丸摘除组大鼠缘核内AR蛋白的表达和睾丸摘除并用睾酮替代组大鼠缘核内AR蛋白的表达接近。说明去睾丸大鼠阻断其内源性雄激素后,对缘核AR蛋白表达影响甚小,而补充外源性雄激素对此影响不大。     

Reinnervated eye muscles do not respond to impulses in foreign nerves

Normal movements return to carp eyes after section and regeneration of the IIIrd and IVth nerve trunks. Two months after reinnervation, records of impulses in the inferior oblique nerve during tilting of the body show activity of the normal motoneurons to that muscle, together with discharge patterns characteristic of the antagonistic superior oblique and some of the rectus muscles. These axons must have found their way into the inferior oblique trunk during sprouting at the lesion and must be maintained after reinnervation. Impulses from foreign axons are without detectable effect on eye movement and therefore must be blocked at their termination in the muscle. Previous study of cross-innervated and doubly innervated fish eye muscles revealed only structurally normal neuromuscular junctions. Transmission from foreign junctions in multiply innervated muscle is blocked by competitive molecular recognition and control mechanisms that do not cause degeneration.     

外源雄激素促进绵羊附睾GPx5基因的表达

为研究外源雄激素丙酸睾酮对绵羊附睾特异表达基因谷胱甘肽过氧化酶5(GPx5)的影响,应用酶联免疫吸附(ELISA)法检测血清和附睾头部内睾酮(T)、二氢睾酮(DHT)的含量,及附睾头部雄激素受体(AR)蛋白表达量;应用实时荧光定量PCR(RT-PCR)技术检测了附睾头部GPx5-mRNA和AR-mRNA相对表达量;并结合免疫印迹(WB)法检测了附睾头部GPx5蛋白相对表达量。结果表明:丙酸睾酮处理(TPT)组与对照组相比绵羊血清DHT含量,附睾头部T含量、DHT含量均显著提高,分别是对照组的0.5、6.0、0.8倍;GPx5-mRNA和ARmRNA相对表达量显著提高,分别是对照组的0.75和0.77倍(P0.05);AR及GPx5蛋白表达量显著提高,分别是对照组的0.63和0.58(P0.05)。因此,外源雄激素丙酸睾酮可大量提高绵羊附睾头部GPx5基因的表达,对绵羊附睾头部GPx5基因的表达具有促进作用。     

Aggression in adult mice: modification by neonatal injections of gonadal hormones

Incidence of spontaneous aggression in adult male mice given a single injection of estradiol benzoate (0.4 milligram) when they were 3 days old was less than that of controls injected with oil. Aggressiveness was increased among adult females injected with either estradiol or testosterone propionate (1 milligram) at the same age. The increased aggressiveness noted among females given androgen was further documented during subsequent mating tests, when these females often attacked, wounded, and, in one case, killed naive males.     

蛙、蟾蜍延脑内控制发声运动核团定位的比较研究

应用 HRP 逆行追踪技术,通过在发声肌注射 HRP,对无尾两栖类蛙和蟾蜍延脑内发声核团进行定位比较。结果表明。(1)三种动物延脑内支配发声肌运动的核团均为舌咽—迷走运动核(nIx-x);(2)无尾两栖类中同种动物的雌雄之间nIx-x 的发达程度不同,雄性较雌性发达一些;同科动物相比,nIx-x 的形状及发达程度相近,不同科动物之间则存在差异,蛙科较蟾蜍科发达一些;(3)支配发声肌的感觉神经可能在脑内没有直接投射。     

雄激素对去势大鼠弓状核AR蛋白表达的影响

为了探讨雄激素（androgen）对去势大鼠弓状核（ARC）内雄激素受体（AR）表达的影响。将30只3月龄雄性健康SD大鼠随机分为GM组（睾丸摘除组）、IMC组（假手术组）、GM＋T组（睾丸摘除并用睾酮替代组）,注射雄激素4周后灌注取材。结果表明,睾九摘除组大鼠弓状核内AR蛋白的表达显著减少,睾丸摘除并用睾酮替代组大鼠弓状核内AR蛋白的表达接近正常水平。说明去睾丸大鼠由于缺乏内源性雄激素,引起弓状核内AR蛋白表达减少,而补充外源性雄激素可抑制这一变化。     

Strychnine: its action on spinal motoneurons of cats

In cats strychnine does not alter measurably the potential, threshold, after potentials, or refractoriness of the membrane of the spinal motoneurons. Increased reflexes probably result from increase of excitatory impingement upon motoneurons. Spikes recorded during a rapid succession of nerve impulses produced by strychnine ("strychnine burst") suggest that soma membrane resistance is appreciable during stimulation.     

成年大鼠面神经低位切断后面运动神经元的死亡进程及GDNF的保护作用

目的 观察大鼠面神经低位切断伤后,大鼠面运动神经元死亡的时间进程和胶质细胞源性神经营养因子(GDNF)局部应用对伤后面运动神经元的作用.方法 手术制作大鼠右侧面神经的低位切断伤 GDNF模型,左侧为切断伤 PBS液对照.用HE、甲苯胺蓝染色技术观测面运动神经元死亡情况及其形态学变化.结果 面神经低位切断伤可引起面运动神经元死亡且于伤后4周时达到高峰.损伤后1、2、4、6周时,GDNF侧神经元数量明显多于对照侧(P＜0.01).伤后2、4、6周时,GDNF侧的神经元数量较第1周时均减少(P＜0.01),而第4周与第6周的神经元数量差异无统计学意K(P＞0.05).结论 局部应用GDNF对低位切断伤后的面运动神经元有显著的保护作用,这种作用在损伤4周内完全发挥.     

猪颈部食管传出神经元的起源——用HRP法研究

将 HRP 注入颈部食管壁后,在延髓的两侧面神经后核出现大量密集的中、小型标记细胞,在疑核的全长可见散在的大型细胞,在迷走神经背核可见少量小型细胞,以核的前区腹外侧缘标记细胞较多。在闩以上的孤束内侧核和第一颈髓的中间外侧核(疑后核)也看到零星标记细胞。颈前神经节和星状神经节出现大量标记细胞,而以颈前节标记细胞较多,还多次发现小标记细胞紧偎着大标记细胞配对的现象。     

Specification of jaw muscle identity in zebrafish: correlation with engrailed-homeoprotein expression

Molecules that determine the specific features of individual muscles in vertebrates are unknown. Antibody labeling studies described here revealed a molecular difference among muscles in the zebrafish head, in that two functionally related jaw muscles (the levator arcus palatini and the dilator operculi), and not other head muscles, expressed engrailed-homeodomain proteins. Expression began in mesoderm-derived muscle-precursor cells in the paraxial mesenchyme and continued during muscle morphogenesis and differentiation. Growth cones of trigeminal motoneurons that innervate these muscles associated with the precursors within a few hours of the time they began to express engrailed. It is proposed that the engrailed proteins in these cells establish muscle identity and neuromuscular target recognition.     

鸡嗉囊的副交感神经元定位

本文用１４只１．０～２．５ｋｇ重的成年鸡研究嗉囊的副交感神经元定位。将ＨＲＰ注入嗉囊，动物存活２～４天后心室固定。取迷走神经远神经节、岩神经节和颈静脉神经节及延髓，制成５０μｍ厚的冰冻切片，用Ｍｅｓｕｌａｍ氏ＴＭＢ法反应呈色，明视野观察，结果如下：１．被标记的嗉囊副交感节前神经元出现于迷走神经背侧运动核和中间核内。嗉囊的标记细胞在迷走神经背侧运动核内的分布有局部定位关系。２。被标记的嗉囊感觉神经元出现于远神经节、岩神经节和颈静脉神经节内。     

Monoclonal antibody to acetylcholine receptor: cell line established from thymus of patient with Myasthenia gravis

A human B cell line producing a monoclonal antibody to an antigenic determinant of acetylcholine receptors was established by cloning B cells that had been transformed in vitro by Epstein-Barr virus. The B cells were obtained from the thymus of a patient with myasthenia gravis. The antibody produced by the cell line precipitated acetylcholine receptors from denervated and innervated rat muscle and from human muscle, but did not show detectable response to the acetylcholine receptors from the electric organs of Narke japonica. The monoclonal antibody showed identical binding patterns in innervated and denervated rat muscles. Passive transfer of the monoclonal antibody into rats induced moderate muscle weakness and electromyographic changes characteristic of myasthenia gravis.     

鸡腔上囊传入神经元的分布——HRP法研究

用CB—HRP法研究鸡腔上囊的感觉神经分布,结果表明:初级传入神经元位于T_6—LS_(13)脊神经节内,主要在LS_9—LS_(11)和LS_1—LS_2;初级传入神经元的中枢突在LS_8—LS_(12)髓节沿背角外侧缘延伸,止于中央管背测阳背外测区;部分初级传入神经元位于迷走神经结状节内。     

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.     

Pineal gland: influence on gonads of male rats treated with androgen 3 days after birth

Either blinding or the injection of 1 milligram of testosterone propionate into male Sprague-Dawley rats, 3 days old, results in testes and accessory organs (seminal vesicles and coagulating glands) that are smaller than normal when the rats are 72 days old. The response to blinding is prevented by removal of the pineal gland, whereas the response to treatment with testosterone is unaffected by pinealectomy. Combination of the two treatments in 3-day- old rats causes testes to be less than one-third their normal size at 72 days of age; pinealectomy in these rats permits the reproductive organs to grow to the same size as those in the androgen-treated animals.     

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.