Copulatory behavior can inhibit pregnancy in female rats

If female rats received genital stimulation soon enough after their male partners had ejaculated, sperm transport and subsequent pregnancy were inhibited. Manual stimulation by the experimenter or five intromissions by a male rat were sufficient stimuli to reduce the number of sperm found in the uterus and to reduce the number of uterine implantation sites.     

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.     

Luteinizing hormone-releasing factor potentiates lordosis behavior in hypophysectomized ovariectomized female rats

Subcutaneous injection of luteinizing hormone-releasing factor (LRF) in estrogen-primed hypophysectomized, ovariectomized female rats facilitates the appearance of the lordosis response. The LRF effect on lordosis was seen 90, 180, and 360 minutes after injection. This effect could help to synchronize the female's mating behavior with the ovulatory discharge of luteinizing hormone.     

Nonhormonal basis of maternal behavior in the rat

Rats were tested for induction of maternal behavior by exposing them to young pups continously for 10 to 15 days. Nonpregnant intact, ovariecto-mized. and hypophysectomized females were studied, as well as intact and castrated males. Nearly all the animals exhibited the four main items of maternal behavior and there were only minor differences in the latencies for the onset of maternal behavior among the various groups. It is concluded that all rats have a basic level of maternal responsiveness which is independent of hormonal stimulation.     

Prolactin in the postpartum rat: synthesis and release in the absence of suckling stimulation

Postpartum female rats deprived of suckling stimulation while being kept continuously with pups nonetheless suspended ovarian cyclicity for an average of 16 days and responded to uterine trauma by forming deciduomata. These results show that the extramammary stimulation afforded by young is alone capable of sustaining prolactin output from the adenohypophysis of the postpartum rat.     

Object-carrying by rats: an approach to the behavior produced by brain stimulation

Rats were provided with opportunity to turn reinforcing hypothalamic stimulation on and off by traversing back and forth across a chamber. When provided with edible and inedible objects, all animals that self-stimulated carried them from the stimulation to the nonstimulation side. Neither food deprivation nor a history of stimulus-bound eating produced a preference for the edible objects. Equivalent stimulation provided without regard to the animals' location in the chamber did not elicit object-carrying. Results are interpreted in terms of the natural conditions which normally elicit this species-specific unit of behavior. Implications for understanding other behavior patterns elicited by hypothalamic stimulation are suggested.     

Olfactory bulb removal eliminates maternal behavior in the mouse

Olfactory bulb removal eliminated maternal behavior in lactating and in virgin mice. The results are in contrast to the generally accepted concept of multisensory control of mammalian maternal behavior.     

Decay of female sexual behavior under parthenogenesis

A laboratory strain of Drosophila mercatorum has existed for 20 years without males and therefore without natural selection operating to maintain the genetic basis of female mating behavior. The females of this strain have recently experienced a genetic impairment of mating capacity. This observation exemplifies the mode of evolution of vestigial characters and supports Muller's theory that random mutation will tend to destroy the genetic basis of a character from which selection has been removed.     

Empathy and pro-social behavior in rats

Whereas human pro-social behavior is often driven by empathic concern for another, it is unclear whether nonprimate mammals experience a similar motivational state. To test for empathically motivated pro-social behavior in rodents, we placed a free rat in an arena with a cagemate trapped in a restrainer. After several sessions, the free rat learned to intentionally and quickly open the restrainer and free the cagemate. Rats did not open empty or object-containing restrainers. They freed cagemates even when social contact was prevented. When liberating a cagemate was pitted against chocolate contained within a second restrainer, rats opened both restrainers and typically shared the chocolate. Thus, rats behave pro-socially in response to a conspecific's distress, providing strong evidence for biological roots of empathically motivated helping behavior.     

Neuronal correlates of behavior in freely moving rats

Firing patterns of single neurons in the hypothalamus, preoptic area, midbrain reticular system, and hippocampus of awake, freely moving female rats were temporally correlated with exploratory sniffing and vibrissa twitching, feeding, lordosis, locomotion, and (or) arousal. These relationships were remarkably stable during continuous observations lasting many hours. During extended periods when certain of these movements were not performed, the correlated neurons showed no action potentials for minutes at a time. Electrical stimulation at certain recording sites elicited behavior patterns whose spontaneous occurrence was accompanied by neuronal activation. Self-stimulation was elicited from sites spontaneously activated during exploratory behavior.     

催乳素的研究进展

催乳素(Prolactin,简称PRL)的名称最早来自它能刺激鸽子嗉囊的上皮细胞增生,生成嗉囊乳。这也是现在PRL生物测定的依据。近年来的研究发现,PRL除具有促进乳腺发育、启动泌乳和维持泌乳的功能外,还参与个体生殖生理的调控、免疫活动及渗透压调节、神经系统信号传递等。长期以来人们一直认为PRL是垂体前叶嗜酸细胞、妊娠子宫蜕膜和免疫细胞等分泌的一种蛋白激素。近年来的动物实验发现,它广泛分布于垂体外的很多组织器官。其受体(PRLR)在鸽子嗉囊上皮组织、大鼠乳腺、肺、肝和人淋巴细胞等处均有发现,并对这些组织的生长分化、细胞分裂…     

Heart rate changes after reinforcing brain stimulation in rats

Cardiac responses to hypothalamic and septal stimulation are polyphasic, the first component being accelerative. As interstimulus intervals are decreased, only accelerative components appear, but prestimulus heart rates ("background levels") are decreased upon septal and are either increased or unchanged upon hypothalamic stimulation. The suggestion that parasympathetic responses accompany reinforcing brain stimulation was not supported.     

不同品种母猪哺乳期防御性攻击行为研究

文章通过评价哺乳期母猪防御性攻击行为,比较哺乳期民猪、长白及大白母猪防御性攻击行为差异,分析母猪防御性攻击行为与母性行为关系。在"仔猪遇险"和"仔猪呼救"试验中,民猪母猪防御性攻击行为极显著强于长白和大白母猪(P0.01);在"接近圈栏"试验中,民猪母猪哺乳期前两周防御性攻击行为显著强于大白母猪(P0.05)。长白与大白母猪相比,除在哺乳期第2周防御性攻击有显著差异外(P0.05),其他时间两品种无差异。母猪防御性攻击行为与母猪在仔猪被压时反应存在极显著正相关(P0.01);与母猪姿势转换频率存在极显著负相关(P0.01)。由此可见,民猪母猪哺乳期具有较强防御性攻击行为,母猪姿势转换频率较低,对仔猪被压反应更强烈,减少仔猪被压风险。     

Reproductive development in a female songbird: differential stimulation by quality of male song

Female canaries exposed to playback of large repertoires of male songs built nests faster and laid more eggs than did those females exposed to smaller song repertoires: females are attentive to attributes of male song, and their choices have played a role in the evolution of oscine singing behaviors.     

Microwaves: effect on thermoregulatory behavior in rats

Rats, with their fur clipped, pressed a lever to turn on an infrared lamp while in a cold chamber. When they were exposed to continuous-wave microwaves at 2450 megahertz for 15-minute periods, the rate at which they turned on the infrared lamp decreased as a function of the microwave power density, which ranged between 5 and 20 milliwatts per square centimeter. This result indicates that behaviorally significant levels of heating may occur at an exposure duration and intensities that do not produce measurable changes in many other behavioral measures or in colonic temperature. Further study of how microwaves affect thermoregulatory behavior may help us understand such phenomena as the reported "nonthermal" behavioral effects of microwaves.     

Suppression of the development of female mating behavior by estrogen administered in infancy

The administration of estradiol benzoate subcutaneously to 4-day-old female rats resulted in reduced mating in response to estrogen and progesterone in adulthood.