Compulsive sexual activity induced by p-chlorophenylalanine in normal and pinealectomized male rats

p-Chlorophenylalanine depletes brain serotonin and induces longlasting sexual excitation in male rats. The effect of p-chlorophenylalanine is potentiated by pargyline. Administration of 5-hydroxytryptophan to rats treated with p-chlorophenylalanine plus pargyline blocks the sexual excitation. p-Chlorophenylalanine also elicits sexual excitation in pinealectomized rats; this effect is not mediated by the lack of indole hormones in the pineal but may be the consequence of depletion of 5-hydroxytryptophan in the brain and the resulting imbalance between 5-hydroxytryptophan and catecholamine activity in the central nervous system.     

Testosterone regulation of sexual reflexes in spinal male rats

Castrated male rats with complete midthoracic spinal transections were maintained on exogenous testosterone; they showed intermittent clusters of genital responses consisting of erections, quick flips, and long flips of the penis when gentle pressure was con stantly applied to its base. The number of these genital responses per 30-minute test was markedly influenced by withdrawal or administration of testosterone.     

Infantile experience with suckling odors determines adult sexual behavior in male rats

Because infant rats learn about odors that elicit suckling, and because certain chemosensory cues that help elicit mating behavior in adults are similar to those that elicit suckling, an experiment was undertaken to assess the influence of suckling-associated odors experienced during infancy on adult sexual behavior. Rat pups lived with and suckled dams whose nipple and vaginal odors were altered with citral, a lemon scent. The rats were weaned and never exposed again, until testing, to citral or females. At about 100 days of age, the males were paired in mating tests with a normal sexually receptive female or with a sexually receptive female that had been treated perivaginally with citral immediately before testing. The males ejaculated readily when paired with citral-treated females but were slow to achieve ejaculation when paired with normal females. These findings implicate an infantile experience as a determinant of adult sexual behavior in a mammal.     

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.     

Humoral mediation of radiation-induced motivation in parabiont rats

Parabiont rat pairs with a skin-vascular anastomosis were used to test for a radiation-induced transferable humoral factor which would motivate aversive conditioning in a nonirradiated (shielded) recipient. The shielded partner, by tasting saccharinflavored fluid shortly after its partner was x-irradiated (360 roentgens), was aversively conditioned to saccharin. This was interpreted as evidence for a humoral motivating factor.     

Inhibitory centers in sexual behavior in the male rat

Small lesions placed near the diencephalic, mesencephalic junction, in either the lateral or medial mammillary region, resulted in an increase of copulatory behavior. This increase was expressed both by increased numbers of copulation plugs formed per 14-day interval and by increased percentage of days on which copulation occurred. Inhibitory structures thus form an essential part of the circuitry involved in mediation of sex behavior in the male.     

Pheromonally induced sexual maturation in females: regulation by the social environment of the male

Social subordination, which suppresses gonadal function in juvenile and adult male house mice, also suppresses the activity of an androgen-dependent urinary pheromone that accelerates the rate of sexual maturation in juvenile females. Pheromone production may also be suppressed by the presence of pregnant or lactating females. This suggests that the social environment may influence the fertility of population females by altering urinary pheromone activity in the male.     

Hormone-mediated nutritional control of sexual behavior in male dung flies

Male Scatophaga stercoraria must prey on other Diptera before they display sexual behavior, develop the accessory cells of their ejaculatory ducts, and achieve full elongation of the testes. The corpus allatum also becomes enlarged after predation and is necessary for the onset of sexual behavior and development of reproductive organs. The complex diet consumed during predation apparently activates the corpus allatum, and the hormone released acts independently on organ growth and sexual behavior.     

Control of pain motivation by cognitive dissonance

Responses by humans to painful electric shocks are significantly modified at subjective, behavioral, and physiological levels by verbal manipulations of degree of choice and justification for further exposure to the aversive stimuli. Pain perception, learning, and galvanic skin resistance are altered under these conditions of "cognitive dissonance," as they are by reductions in voltage intensity.     

Plasma testosterone levels in the male rhesus: influences of sexual and social stimuli

Four adult male rhesus monkeys were provided access individually to a group of receptive females. Each male assumed dominance and engaged in frequent copulations. Plasma testosterone levels increased two- to threefold during this period. Next, each male was subjected to sudden and decisive defeat by a large all-male group, and plasma testosterone fell following this experience. Two males were later reintroduced to the females, and plasma testosterone rose rapidly to the previous elevated levels.     

雄性“肾阳虚”亚健康大鼠模型的研究

〔摘要〕目的研究雄性“’肾阳虚”亚健康大鼠模型,为调理男性肾阳虚亚健康找寻科学配方〔方法控制用药剂 量及灌胃时间,用维生素B,建立雄性“’肾阳虚”亚健康大鼠模型,检测腺垂体一辜丸轴激素、氧化损伤因子及抗氧化 损伤因子、辜丸组织微细结构作为判断亚健康组织学依据〔结果与正常大鼠相比较,模型大鼠血清FSH,LH,T均 降低,均有统计学意义;模型大鼠rfn.清SOD卜降,差异有统计学意义(P<0.05 ) ; MDA增加,差异有统计学意义(P< 0.01) ;模型大鼠辜丸组织曲细精管规则,管腔变大,精子尾部有融合现象,生精细胞层次减少,排列较紊乱,出现空 泡现象结论运用维生素B,建立的雄性“’肾阳虚”亚健康大鼠模型成功     

Pineal gland: influence on development of copulation in male rats

Male rats reared in constant darkness, pinealectomized 3 days after birth, and tested for copulation starting at 24 days of age, mounted receptive females more frequently and showed pelvic thrusting at an earlier age than littermate controls.     

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.     

Adaptive plasticity in female mate choice dampens sexual selection on male ornaments in the lark bunting

Theory on the evolution of ornamental male traits by sexual selection assumes consistency in selection over time. Temporal variation in female choice could dampen sexual selection, but scant information exists on the degree to which individual female preferences are flexible. Here we show that in lark buntings sexual selection on male traits varied dramatically across years and, in some cases, exhibited reversals in the direction of selection for a single trait. We show that these shifts are probably because of flexibility in mate choice by individual females and that they parallel shifts in the male traits that predict female reproductive success in a given year. Plasticity in choice and concomitant reversals in mating patterns across time may weaken the strength of sexual selection and could maintain genetic variation underlying multiple sexual ornaments.     

Requirement for DARPP-32 in progesterone-facilitated sexual receptivity in female rats and mice

DARPP-32, a dopamine- and adenosine 3',5'-monophosphate (cAMP)-regulated phosphoprotein (32 kilodaltons in size), is an obligate intermediate in progesterone (P)-facilitated sexual receptivity in female rats and mice. The facilitative effect of P on sexual receptivity in female rats was blocked by antisense oligonucleotides to DARPP-32. Homozygous mice carrying a null mutation for the DARPP-32 gene exhibited minimal levels of P-facilitated sexual receptivity when compared to their wild-type littermates. P significantly increased hypothalamic cAMP levels and cAMP-dependent protein kinase activity. These increases were not inhibited by a D1 subclass dopamine receptor antagonist. P also enhanced phosphorylation of DARPP-32 on threonine 34 in the hypothalamus of mice. DARPP-32 activation is thus an obligatory step in progestin receptor regulation of sexual receptivity in rats and mice.     

Enhancement of flicker by lateral inhibition

Sinusoidal modulation of illumination on the compound eye of the horseshoe crab, Limulus, produces a corresponding variation in the rate of discharge of optic nerve impulses. Increasing the area of illumination decreases the variation at low frequencies of modulation, but unexpectedly enhances-or "amplifies"-the variation at the intermediate frequencies to which the eye is most sensitive. Both effects must result from inhibition since it is the only significant lateral influence in this eye.     

An antimicrobial peptide gene found in the male reproductive system of rats

Little is known about the innate defense mechanisms of the male reproductive tract. We cloned a 385-base pair complementary DNA and its genomic DNA named Bin1b that is exclusively expressed in the caput region of the rat epididymis and that is responsible for sperm maturation, storage, and protection. Bin1b exhibits structural characteristics and antimicrobial activity similar to that of cationic antimicrobial peptides, beta-defensins. Bin1b is maximally expressed when the rats are sexually mature and can be up-regulated by inflammation. Bin1b appears to be a natural epididymis-specific antimicrobial peptide that plays a role in reproductive tract host defense and male fertility.     

异黄酮对雄性大鼠芳香化酶活性及骨骼肌生长的影响

研究3种异黄酮(Da、IPF和7HF)对雄性大鼠芳香化酶活性及骨骼肌生长的影响。试验选用20只28日龄雄性SD大鼠,随机分成4组,每组5只,其中1组为对照组,另外3组在每千克日粮中分别添加5mg的Da、IPF和7HF。实验结果表明,Da、IPF和7HF均能升高腿肌中RNA／DNA的比值,分别较对照组升高了19．09％、9．09％和15．45%;同时显增加血清中睾酮的含量,降低血清中雌二醇的含量,抑制睾丸组织中芳香化酶的活性。提示异黄酮(Da、IPF、7HF)通过抑制芳香化酶活性而降低睾酮向雌二醇的转化,使体内睾酮含量升高,有助于促进动物的生长发育。