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PubMed1994

Pheromonotropic and pheromonostatic activity in moths.

Pheromone biosynthesis in many species of moths requires a pheromonotropic neurosecretion, the pheromone biosynthesis activating neuropeptide (PBAN), from the brain-subesophageal ganglion-corpora cardiaca complex. Some investigations suggest that PBAN is released into the hemolymph and acts directly on sex pheromone glands (SPG) via a Ca++/calmodulin-dependent adenylate cyclase. Others suggest, however, that PBAN acts via octopamine that is released by nerves from the terminal abdominal ganglion innervating the SPG. These findings suggest that there are controversies on the mode of action of PBAN and other pheromonotropic factors, sometimes even within the same species. Mating in many insects results in temporary or permanent suppression of pheromone production and/or receptivity. Such a suppression may result from physical blockage of the gonopore or deposition of pheromonostatic factor(s) by the male during copulation that result in suppressed pheromone production and/or receptivity in females either directly or by a primer effect. In several species of insects, including moths, a pheromonostatic factor is transferred in the seminal fluid of males. Similar to the controversies associated with the pheromonotropic activity of PBAN, sometimes even within the same species, there appear to be controversies in pheromonostasis in heliothines as well. This paper reviews these conflicting findings and presents some data on pheromonostatic and pheromonotropic activity in Heliothis virescens that support and conflict with current information, raising further questions. Answers to some of the questions are partly available; however, they remain to be answered unequivocally.

Animals↗
PubMed2006

Gestational stage sensitivity to ultrasound effect on postnatal growth and development of mice.

BACKGROUND: An experiment was conducted to find out whether ultrasound exposure leads to changes in postnatal growth and development in the mouse. METHODS: A total of 15 pregnant Swiss albino mice were exposed to diagnostic levels of ultrasound (3.5 MHz, 65 mW/cm2, I(SPTP) = 1 mW/cm2 Intensity(Spatial Peak-Temporal Peak), I(SATA) = 240 mW/cm2 Intensity(Spatial Average-Temporal Average)) for 30 min for a single day between days 10 and 18 of gestation (GD 10-18). Virgin female mice were placed with same age group males for mating in the ratio 2 females : 1 male and examined the next morning for the presence of vaginal plug, a sign of successful copulation. The females with vaginal plugs were separated and labeled as 0-day pregnant. Maternal vaginal temperature was also measured. A sham exposed control group of 15 pregnant mice was maintained for comparison. All exposed as well as control animals were left to complete gestation and parturition. Their offspring were used in our further studies. They were monitored during early postnatal life for standard developmental markers, postnatal mortality, body weight, body length, head length, and head width, and growth restriction was recorded up to 6 weeks of age. RESULTS: An exposure to ultrasound induced nonsignificant deviations in the maternal vaginal temperature or developmental markers. Significant low birth weight was observed in the present study, after exposure at GD 11, 12, 14, and 16. However, 14 and 16 days postcoitus during the fetal period appears to be the most sensitive to the ultrasound effect, in view of the number of different effects as well as severity of most of the observed effects when exposed on these gestation days. CONCLUSIONS: The results indicate that diagnostic ultrasound can induce harmful effects on mouse growth and development when given at certain critical periods of gestation.

Animals↗
PubMed2003

Pretreatment with periodate-oxidized adenosine enhances developmental toxicity of inorganic arsenic in mice.

BACKGROUND: Inorganic arsenic, given by injection to pregnant laboratory animals, can induce malformations. Arsenic methylation can be inhibited by periodate-oxidized adenosine (PAD). Severe human health effects from high chronic arsenic exposure have mainly been reported in populations with significant levels of malnutrition, which may enhance toxicity by diminishing arsenic methylating capacity. This study sought to determine the effect of inhibition of arsenic methylation on the developmental toxicity of arsenic in a mammalian model. METHODS: PAD (100 microM/kg, i.p.), was given to pregnant CD-1 strain mice 30 min before 7.5mg/kg sodium arsenite [As(III)], i.p., or 17.9 mg/kg sodium arsenate [As(V)], i.p., on gestation day 8 (GD 8; copulation plug = GD 0). Control dams received As(III), As(V), or PAD alone or were untreated. Test dams were killed on GD 17, and their litters were examined for mortality and gross and skeletal defects. RESULTS: Pretreatment with PAD before either arsenical resulted in increased maternal toxicity and lower fetal weights. Pretreatment also caused higher prenatal mortality, with 8 of 21 and 5 of 17 litters totally resorbed in the PAD plus As(III) and PAD plus As(V) treatment groups, respectively. Significant increases in the incidences of exencephaly, ablepharia, and anomalies of the vertebral centra, sternebrae, and ribs were also associated with PAD pretreatment. Short tail (3 fetuses in 3 litters) was seen only following PAD plus As(III) treatment. CONCLUSIONS: These results demonstrate that the developmental toxicity of inorganic arsenic can be enhanced by PAD, due possibly to inhibited methylation of arsenic.

Abnormalities, Drug-Induced↗
PubMed2003

Afferent connections of the parvocellular subparafascicular thalamic nucleus in the rat: evidence for functional subdivisions.

The parvocellular subparafascicular nucleus of the thalamus (SPFp) consists of separate subdivisions, i.e., a medial portion containing galanin-immunoreactive (-IR) axons and a lateral portion containing calcitonin gene related peptide (CGRP)-IR neurons and fibers. These subdivisions appear to have distinct functional roles. In particular, ejaculation-induced Fos expression is expressed in the medial SPFp. Hence, it was hypothesized that medial SPFp is involved in relay of copulation-related information. In contrast, lateral SPFp is involved in the processing of auditory and visual signals involved in fear-conditioned responses. Here we tested the hypothesis that medial and lateral subdivisions of SPFp receive different sets of afferents and that these differences contribute to the separate functional roles of the two subdivisions. Inputs to medial and lateral SPFp were identified following injections of FG restricted to either division in male rats. The medial SPFp receives unique inputs from lumbar spinothalamic cells and brain regions involved in processing of visceral stimuli, supporting the hypothesis that the medial SPFp is involved in the relay of genitosensory information critical for the expression of male sexual behavior. The afferents of the lateral SPFp include brain regions involved in processing of visual and auditory signals and support a role for this subdivision in relay of visual and auditory information. Thus, the two subdivisions of SPFp are anatomically and functionally distinctive.

Afferent Pathways↗
PubMed2005

Forebrain substrates of reward and motivation.

Electrical stimulation of the medial forebrain bundle can reward arbitrary acts or motivate biologically primitive, species-typical behaviors like feeding or copulation. The subsystems involved in these behaviors are only partially characterized, but they appear to transsynaptically activate the mesocorticolimbic dopamine system. Basal function of the dopamine system is essential for arousal and motor function; phasic activation of this system is rewarding and can potentiate the effectiveness of reward-predictors that guide learned behaviors. This system is phasically activated by most drugs of abuse and such activation contributes to the habit-forming actions of these drugs.

Afferent Pathways↗
PubMed2007

Sex and species differences in tyrosine hydroxylase-synthesizing cells of the rodent olfactory extended amygdala.

The bed nucleus of the stria terminalis (BST) and the medial amygdala (MeA) are anatomically connected sites necessary for chemosensory regulation of social behaviors in rodents. Prairie voles (Microtus ochrogaster) are a valuable model for studying the neural regulation of social behaviors because, unlike many other rodents, they are gregarious, pair bond after copulating, and are biparental. We herein describe sex and species differences in immunoreactivity for tyrosine hydroxylase (TH), the rate-limiting enzyme for catecholamine synthesis, in the BST and MeA. Virgin male prairie voles had a large number of TH-immunoreactive cells in areas analogous to the rat principal nucleus of the BST (pBST) and the posterodorsal medial amygdala (MeAPd). Virgin female prairie voles had far fewer TH-immunoreactive cells in these sites ( approximately 17% of the number of cells as males in the pBST, approximately 35% of the number of cells in the MeAPd). A few TH-immunoreactive cells were found in the BST of male and female hamsters and meadow voles, but not in rats. The MeApd also contained a few TH-immunoreactive cells in male and female hamsters and male meadow voles, but not rats. Castration greatly reduced the number of TH-immunoreactive cells in the male prairie vole pBST and MeAPd, an effect that could be reversed with testosterone. Furthermore, treating ovariectomized females with testosterone substantially increased TH-immunoreactive cells in both sites. Therefore, a species-specific sex difference in TH expression is found in a chemosensory pathway in prairie voles. Expression of TH in these sites is influenced by circulating gonadal hormones in adults, which may be related to changes in their display of social behaviors across the reproductive cycle.

Amygdala↗
PubMed1976

Hormone concentrating cells in vocal control and other areas of the brain of the zebra finch ( Poephila guttata).

Using the autoradiographic method in the zebra finch (poephila guttata), areas of the brain were identified which contain cells which accumulate testosterone. Among these areas are the caudal nucleus of the hyperstriatum ventrale, nucleus intercollicularis of the midbrain, and the tracheosyringeal portion of the hypoglossal nucleus of the medulla (nXIIts). These three are known to control or influence androgen dependent song and other vocalizations of passeriform birds, and nXIIts is composed of the motoneurons innervating the vocal (syringeal) muscles. Other areas containing hormone-concentrating cells are the medial preoptic area, nucleus periventricularis magnocellularis of the hypothalamus, dorsal infundibular layers, dorsomedial thalamus, lateral septum, magnocellular nucleus of the anterior neostriatum, periventricular medial neostriatum, nucleus taeniae of the archistriatum, and ventral paleostriatum augmentatum. Accumulation by cells in the preoptic area, hypothalamus, and limbic forebrain is consistent with a general vertebrate pattern of distribution of brain cells which accumulate sex steroids. Some of these same areas may be involved in the control of androgen dependent events such as courtship, copulation, aggression, and feedback regulation of the hypophysis.

Animals↗
PubMed1988

The nervous system of the male Dinophilus gyrociliatus (Polychaeta, Dinophilidae): II. Electron microscopical reconstruction of nervous anatomy and effector cells.

All neuronal cells in the dwarf male of the dimorphic polychaete species Dinophilus gyrociliatus were individually identified by means of serial ultrathin sections. Altogether 68 neural cells--including 40 sensory neurons and 2 glial cells--constitute a small but complex nervous system. Fifty-three neural cells are located in three pairs of ganglia and connected by paired nerve cords. The prominent frontal ganglia, each consisting of a well-developed neuropile and surrounded by 20 or 21 neural cells, represent the animal's brain. The ventral ganglia contain only 2 neurons each. The penis ganglia--four cells each--are associated with the copulatory organ. A conspicuous circumpenial fiber mass surrounds the basal part of the penis. The effector cells--22 multiciliated epidermal cells, 34 muscle cells, and different gland cells (?)--were also reconstructed and their innervation was partly elucidated. Sensory-motor neurons were unambiguously identified. They are discussed in regard to the small body size of the animal. The male's nervous organization resembles a very simple rope ladder and may represent a reduced derivative of a nervous system in normal-sized males of monomorphic species. Similarities, however, also occur with the developing nervous system of a planktotrophic metatrochophore. The neuronal organization, with its two centers (frontal ganglia and ventral ganglia vs. penis ganglia and circumpenial fiber mass), accords well with the bipartite behavioral pattern, which is entirely devoted to locomotion and copulation, respectively.

Animals↗
PubMed1982

Sexual imprinting in male Japanese quail: the effects of castration at hatching.

This study investigated whether gonadal hormones are required for sexual imprinting in male Japanese quail during the period of exposure to the imprinting stimulus. Brown males were either castrated or laparotomized on the day of hatching. Between Days 10 and 30 of age castrated males (N = 15) and intact laparotomized males (N = 10) were exposed individually to white females. A 2nd group of intact laparotomized males (N = 13) were exposed to brown females. When adult (Day 54), 7 of the castrated males were treated with testosterone propionate (TP): the remaining 8 castrated males and intact groups received saline. All males were given choices between novel white and novel brown females starting on Day 62. The TP-treated castrated males behaved like intact white-exposed males, preferring to approach and copulate with white females significantly more readily than did intact brown-exposed males. The untreated castrated males showed no sexual behavior. The results indicate that gonadal hormones are not required during the period of exposure to an imprinting stimulus in male Japanese quail.

Animals↗
PubMed1996

Multilocus fingerprinting and single locus analyses in the great tit for paternity determination.

In order to arrive at detailed information about the occurrence of alternative reproductive tactics in the great tit (Parus major) we examined parental lineages by multilocus fingerprinting in 51 great tit broods containing 429 nestlings. In 45% of the broods at least one nestling was found to stem from copulations with males other than the social mate of the female. Single broods contained up to 62% extra-pair young (EPY). Single locus profiling revealed how many fathers were involved in extra-pair paternity (EPP) within each brood: In most cases a single male is the genetic father of all EPY in a given brood.

Alleles↗
PubMedDate not supplied

Dominant lethal study of sulfur mustard in male and female rats.

Sulfur mustard (HD) (bis(2-chloroethyl)sulfide) is a strong alkylating agent with known mutagenic and suspected carcinogenic properties, but occupational health standards have not been established. The purpose of this study was to determine the dominant lethal effect in male and female rats dosed orally with HD, for which currently available data are ambiguous. Sprague-Dawley rats of each sex, 6-7 weeks old, were orally administered 0, 0.08, 0.20 or 0.50 mg kg-1 HD 5 days a week for 10 weeks, after which dominant lethal studies were conducted during the post-exposure period. The studies were conducted in two phases: a female dominant lethal phase in which treated or untreated males were mated with treated females and their fetuses were evaluated 14 days after copulation; and a male dominant lethal phase in which treated males cohabited with untreated females for 5 days and fetuses were evaluated 14 days after the mid-point of the week of cohabitation, for each of 10 weeks. In addition, motility, population size and morphology were measured in sperm obtained from the cauda epididymis. Parental growth rates were reduced in both sexes treated with the high level of HD. Female dominant lethal effects were not observed, although significant male dominant lethal effects were observed in HD-exposed male rats mated to untreated females at 2 and 3 weeks' post-exposure. These effects, which included increases of early fetal resorptions and preimplantation losses and decrease in total live embryo implants, were most consistently observed at a dose of 0.50 mg kg-1. A significant P(P < 0.05) increase in the percentage of abnormal sperm was detected in males exposed to 0.50 mg kg-1 HD. The timing of dominant lethal effects is consistent with an effect during the post-meiotic stages of spermatogenesis, possibly involving the generally sensitive spermatids.

Animals↗
PubMed2001

Distribution of sex steroid hormone receptors in the avian brain: functional implications for neural sex differences and sexual behaviors.

Developmental and seasonal changes in the production of androgens, estrogens, and progestins seem to control sex-specific differentiation and seasonal changes in appetitive and consummatory sexual behaviors of birds. This results in profound sex differences in the quality (sex-specific) or quantity (sex-typical) of behaviors such as courtship, territoriality, or copulation. Steroids affect the brain by binding to intracellularly located receptors. The same brain areas express androgen, estrogen, and progesterone receptors in male and female brains. Sex differences in these genetically determined patterns occur in the size of neuron populations that intrinsically express sex steroid receptors. Further permanent sex differences are subsequent to degenerative fates of receptor expressing neuron populations during ontogeny. Transient sex differences in receptor expression appear to be due to area-specific up- and down-regulation of receptor levels, reflecting transient changes in the level of circulating steroids, changes in environmental conditions, or in the physiological status of the individuals. In particular, intrinsic sex differences in the expression pattern of sex steroid receptors and steroid-independent regulation of the expression level of these receptors in the brain are limiting mechanisms for gonad-dependent sexual development and activities.

Animals↗
PubMed2003

Dwarf male of Symbion pandora (cycliophora).

This study clarifies the identity and development of the male in the life cycle of Symbion pandora. The male is not produced directly by the feeding stage, as previously thought, but arises as a distinct individual from budding cells inside an intermediate stage named the Prometheus larva. The morphology and the development of the two distinct stages are described with light and electron microscopy. Furthermore, the following terminology is suggested to clearly distinguish between the different individuals: 1) the Prometheus larva, which is the free-swimming individual being produced inside the feeding stage; 2) the attached Prometheus larva on the feeding stage, which mostly degenerates following settlement, except for the internal budding cells; and 3) the dwarf male, which is the ciliated, sexually mature stage. The budding cells inside the attached Prometheus larva usually develop two internal dwarf males. Each dwarf male is heavily ciliated and has a well-developed nervous system with a relatively large brain, numerous gland and muscle cells, testis with bundles of sperm, and one penial structure. The male lacks a gut, as in the other free stages in the life cycle of Symbion pandora. This study also indicates that the dwarf male is freed from the attached Prometheus larva. Copulation, which has not been observed yet, probably takes place between a free-swimming male and the female, either while the female is released or afterwards.

Animals↗
PubMed2004

Functional morphology of the reproductive system of Galathea intermedia (Decapoda: Anomura).

Spermatophore formation in Galathea intermedia begins in the proximal part of the vas deferens. The contents subsequently form a spermatophoric ribbon, the so-called "secondary spermatophore," in its distal part. A strongly muscular ductus ejaculatorius is present in the coxa of the fifth pereiopod which builds up pressure for the extrusion of the spermatophoric ribbon. After extrusion, the ribbon is caught by the first gonopod, while the second gonopod dissolves the matrix of the ribbon. During copulation the spermatophores are randomly placed on the sternum of the female, near the genital opening, by the fifth pereiopods of the male. Subsequent ovulation of the female via the genital opening, an active process accomplished through muscular activity, results in fertilization of the eggs by the exploding spermatophores. External intersexes are characterized by both male and female external sexual characters, but in all individuals only male gonads are present. No trace of a female reproductive system could be detected. Thus, these external intersexes are exclusively functional males.

Animals↗
PubMed2006

Silhouettella loricatula (Arachnida, Araneae, Oonopidae): a Haplogyne spider with complex female genitalia.

The female genital system of the oonopid Silhouettella loricatula is astonishingly complex. The genital opening is situated medially and leads into an oval receptaculum that is heavily sclerotized except for the ventral half of the posterior wall that appears chitinized only. A large striking sclerite lying in the posterior wall of the uterus externus is attached anteriorly to the receptaculum and continues dorsally into a globular appendix that bears a furrow. The uterus externus shows a peculiar modification in its anterior wall: a paddle-like sclerite with a nail-like posterior process. This sclerite lies opposite to the furrow proceeding in the globular appendix and may serve females to lock the uterus externus by muscle contractions. Massive muscles connect the sclerite with the anterior scutum of the opisthosoma and with two other sclerites that are attached to the receptaculum and serve as attachments for further muscles. Gland cells extend around a pore field of the receptaculum. They produce secretion that encloses spermatozoa in a discrete package (secretory sac) inside the receptaculum. In this way, the mixing of sperm from different males and thus sperm competition may be severely limited or completely prevented. During a copulation in the laboratory the ejection of a secretory sac that most probably contained spermatozoa was observed, indicating sperm dumping in S. loricatula. The ejection of the secretory sac may be caused by female muscle contractions or by male pedipalp movements. The majority of the investigated females have microorganisms in the receptacula that could represent symbionts or infectious agents. The microorganisms can be identified partly as bacteria. They are enclosed in secretion and are always found in the same position inside the receptaculum.

Animals↗
PubMed2006

Bursa tract diverticulum in the hermaphroditic land snail Arianta arbustorum (Stylommatophora: Helicidae): morphology, function, and evolutionary implications.

A bursa tract diverticulum is widespread in the female part of the hermaphroditic reproductive system of stylommatophoran pulmonates. However, the ultrastructure of the diverticulum is unknown and there is only anecdotal evidence for a spermatophore-dissolving function for this organ. In the present study, we examined the ultrastructure of the diverticulum and investigated histological, histochemical, and morphometric changes at different time intervals after mating in the simultaneously hermaphroditic land snail Arianta arbustorum. The diverticulum in this species of snail is a prominent organ, consisting of a luminal columnar epithelium surrounded by a thick layer of connective tissue. During mating, the diverticulum functions as the site of spermatophore uptake. Within the lumen of the diverticulum the spermatophore wall is dissolved or at least partly broken down. The digested material is taken up by epithelial cells and accumulated in molluscan-specific cells of the connective tissue, the so-called rhogocytes. Subsequent to copulation, the total diameter of the diverticulum increases markedly, reaching a maximum size 12 h after mating, while at the same time the thicknesses of the diverticulum wall and diverticulum epithelium decrease. The length of the diverticulum shows a positive allometry and a high phenotypic variation compared to snail size, which suggests that the diverticulum is under directional sexual selection. We propose that the diverticulum in A. arbustorum has evolved in response to selection pressures imposed by divergent evolutionary interests between male and female function.

Animals↗
PubMed2006

Comparative morphology and cytology of the male sperm-transmission organs in viviparous species of clinid fishes (Clinidae: Teleostei, Perciformes).

This work comprises the first comparative study of the morphology and cytology of the sperm transmission organs in males of 14 species of viviparous clinid fishes (Clinidae, Blennioidei, Teleostei). The form and dimensions of these organs differ among the various species studied. The organs are composed of intra-abdominal ampullae, into which the sperm ducts and urinary bladder anchor, and an external protruding intromittent papilla used for insemination. The form of the ampullae differs among the various species, from pear-shaped to horseshoe-shaped. It increases in dimensions with increasing length of the male. In all the species this organ is covered by a connective-tissue tunic that encompasses both circular and longitudinal striated muscle bundles. The lumina of the ampullae harbor the epididymis, a strongly convoluted and plicated duct, which becomes filled with spermatozeugmata during reproduction. From here, the epididymis continues into the protruding intromittent papillae, where its folds gradually straighten at the apical part of the intromittent organ. The form and dimensions of this copulatory organ also differ in the various species. Papillae bearing taste buds are found on the apical parts of the intromittent organ, and it is probable that these, together with the difference in forms of the organ, help to prevent interspecific copulation.

Animals↗
PubMed2002

Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). III. Sexual segment of the male kidney.

In mature male snakes and lizards, a distal portion of the nephron is hypertrophied in relation to its appearance in females and immature males. This sexual segment of the male kidney apparently provides seminal fluid that is mixed with sperm and released into the female cloaca during copulation. In this article, we provide the first study at the ultrastructural level of seasonal variation in the sexual segment of the kidney of a squamate, the natricine snake Seminatrix pygaea. Previous workers have indicated that the sexual segment is secretory only when the testes are spermatogenically active. The sexual segment of the kidney in S. pygaea does not go through an extended period of inactivity but does show a cycle of synthesis and secretion that can be related to the spermatogenic cycle and mating activity. We show that synthesis of secretory product is initiated with the onset of spermatogenic activity in the spring and culminates with completion of spermiation in the fall. Secretion of the product, however, occurs in a premating period in March when the testes are inactive. Secretion during this premating period is probably necessary to provide time for the passage of the products down the ureter in order to mix with sperm during mating later in spring.

Animals↗