Neuroendocrine and reproductive aspects of adult male rats exposed neonatally to an antiestrogen

The present study was designed to investigate the effects of a single dose of an estrogen antagonist-clomiphene-during neonatal life, on later neuroendocrine system and reproductive performance. Immediately after birth, male pups received clomiphene citrate (s.c.). At adulthood, although testosterone levels and wet weights of reproductive organs were not altered, the treatment induced an increased number of spermatozoa and a delay in the transit time in the cauda epididymis. Additionally, there was impairment of sexual behavior evidenced by a delay in the latencies to the first mount and first intromission. Treated rats also showed decreased dopaminergic and serotonergic neurotransmissions in the hypothalamus and decreased dopaminergic neurotransmission in the striatum. The decreased dopaminergic activity could be related to the lower sexual motivation observed. These results indicate the necessity of preventing exposure to drugs that may impair sexual differentiation, which can compromise later mating success as well as the capacity to generate descendants. (c) 2006 Elsevier B.V. All rights reserved.

Semen and reproductive parameters during some abstinence periods after cigarette smoke exposure in male rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ejaculatory dysfunction in streptozotocin-induced diabetic rats: the role of testosterone

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Copulatory efficiency and fertility in male rats exposed perinatally to flutamide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spermiogenesis and introsperm ultrastructure of Scoloplax distolothrix (Ostariophysi : Siluriformes : Scoloplacidae)

Spermiogenesis in scoloplacids is characterized by initial lateral development of the flagellum, nuclear rotation, medial nuclear fossa formation, complex centriolar migration, and cytoplasmic channel formation. The scoloplacid spermiogenesis is similar to those found in Diplomystidae, the most primitive siluriform family. The scoloplacid spermatozoa have all the main characteristics of introsperm. They exhibit a conic head, a symmetric midpiece, a medial flagellum, and no acrosome. The conic forward-elongated nuclei contain homogeneous chromatin. The thin extremity of the nuclei is strongly curved and along its internal face there is a well-developed membranous compartment. The centrioles are completely inside the medial nuclear fossa, perpendicular to each other and with an electron-dense material between them. In a cross view of the midpiece, the mitochondria form a ring surrounding internally the cytoplasmic channel, and in a longitudinal view they are organized in a row along it. Several elongated vesicles are distributed peripherally, mainly concentrated in the mid-piece basal region. The flagellum contains the classical axoneme (9 + 2) and has two lateral projections or fins. The spermatozoa of scoloplacids share several characteristics with those of Auchenipteridae. Since these two families are not phylogenetically related this similarity seems to be due to convergence once both families are, until now, the only known siluriform families with introsperm.

Ultrastructure of spermiogenesis in Plagioscion squamosissimus (Teleostei, Perciformes, Sciaenidae)

Spermiogenesis in Plagioscion squamosissimus occurs in cysts. It involves a gradual differentiation process of spermatids that is characterized mainly by chromatin compaction in the nucleus and formation of the flagellum, resulting in the spermatozoa, the smallest germ cells. At the end of spermiogenesis, the cysts open and release the newly formed spermatozoa into the lumen of the seminiferous tubules, the spermatozoa do not have an acrosome and are divided into head, midpiece, and tail or flagellum, the spermatozoa of P. squamosissimus are of perciform type with the flagellum parallel to the nucleus and the centrioles located outside the nuclear notch. (C) 1999 Harcourt Publishers Ltd.

Sperm storage structures in the ovary of Helicolenus dactylopterus dactylopterus (Teleostei : Scorpaenidae): An ultrastructural study

The ultrastructure of ovarian sperm storage of Helicolenus dactylopterus dactylopterus is described, before and after the spawning period. The spermatozoa remain inside cryptal structures that are situated in the interlamellar gaps and are connected to the ovarian lumen by a duct. This complex forms a highly specialised structure. During the long storage period, crypts are richly vascularised. Their surrounding simple epithelia have intercellular junctions that may serve to protect the spermatozoa from the female immune system. At the moment during which insemination of mature oocytes occurs, the sperm may be expelled from cryptal structures by means of a spasmodic contraction. During the post spawning period, residual spermatozoa that remain in the crypts are eliminated by cryptal phagocytes. At the end of the process the crypts contain only an amorphous material.

A new genus and two new species of Stevardiinae (Characiformes: Characidae) with a hypothesis on their relationships based on morphological and histological data

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spermatic characteristics and sperm evolution on the subfamily Stevardiinae (Ostariophysi: Characiformes: Characidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Markiana nigripinnis (Perugia, 1891) as a putative member of the subfamily Stevardiinae (Characiformes: Characidae): spermatic evidence

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spermatozoal ultrastructure in three species of the genus Uca Leach, 1814 (Crustacea, Brachyura, Ocypodidae)

Morphological aspects of spermatozoa in marine animals have been used in recent decades as phylogenetic criteria (spermiotaxonomy). This paper presents ultrastructural descriptions of the spermatozoa from Uca maracoani, U. thayeri, and U. vocator. A small portion of the vas deferens of each species was examined under the transmission and scanning electron microscopy. The ultrastructural analysis showed that each spermatophore consists of a varying number of spermatozoa embedded in a dense fibrillar matrix surrounded by a membrane. The spermatozoa of U. maracoani, U. thayeri, and U. vocator are typical of brachyurans. The Voluminous acrosome is characterized by three different layers. The postero-lateral surface of the acrosome is cupped by the reduced cytoplasm, and the anterior surface is covered by the operculum. The perforatorium consists of coiled, helicoidal membranous tubules and is continuous with the cytoplasm. The nucleus is composed by uncondensed chromatin and presents several lateral arms distributed over the entire equatorial plane of the cell. The presence of the apical button is a well defined character among all species of the genus Uca, but in U. thayeri it was not observed. The accessory opercular ring can be found in the three studied species, but in distinct development degree-Two centrioles were detected in U. thayeri and U. vocator, but only one was found in U. maracoani. The presence of centrioles in the mature spermatozoa is the first account for the genus Uca upto-date. Considering the ultrastructure of the spermatozoa of U. maracoani, U. thayeri, and U. vocator, we suggest that these three species partially follow the morphological patterns previously described in other Thoracotremata brachyurans. The absence of the apical button in U. thayeri spermatozoa may represent an evolutionary novelty in the genus Uca. (C) 2007 Elsevier Ltd. All rights reserved.

Cytodifferentiation during the spermatogenesis of the hermaphrodite caridea Exhippolysmata oplophoroides

Among the decapods, the caridean Exhippolysmata oplophoroides has been described as a simultaneous protandric hermaphrodite, seeing that it presents a male initial stage followed by a hermaphrodite one in which it can function as male and as female. This work had the aims of characterizing the microscopical morphology of the male portion of the ovotestes gonads from E. oplophoroides, at the different development stages, identifying each cell from the germ lines during spermatogenesis, as well as describing the ultramorphology of spermatozoans in the terminal region of the vasa deferentia. Shrimps were collected in Ubatuba, north coast of São Paulo, and their male gonads and the ampoule were removed, fixed and processed according to histological routine and for scanning electron microscopy. The testicular portion is divided in lobes, inside which cells at the same stage of the spermatogenic cycle are observed, with prevalence of spermatogonia and spermatocytes at stages I, II and V of gonad development, whereas spermatids and spermatozoans are found at stages III and IV, respectively. Ultramorphology of the terminal portion of the vasa deferentia exhibits mature aflagellated spike-shaped spermatozoans, encased in secretion and between membrane foldings that will constitute the spermatophores. Despite presenting reproductive characteristics common to other decapods. E. oplophoroides shows spermatozoans as well as spermatophore with typical morphology, which is important for its identification and taxonomy. Further, this species showed polysaccharide secretions where the spermatozoa are immerse as far as the testicular portion, which could have a roe in their transport and nutrition as well as spermatophore constitution and/or fixation; differently, other caridean species begin spermatophore formation during the passage of the gametes through the vasa deferentia. (C) 2010 Elsevier Ltd. All rights reserved.

Morphology and histology of male and female reproductive systems in the inseminating species Scoloplax distolothrix (Ostariophysi : Siluriformes : Scoloplacidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spermiogenesis and spermatozoal ultrastructure in Trichomycteridae (Teleostei: Ostariophysi: Siluriformes)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spermiogenesis and sperm ultrastructure in ten species of Loricariidae (Siluriformes, Teleostei)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)