The mechanism of the periodical opening and closing of the vaginal orifice in the guinea‐pig

Kelly, G. Lombard; Papanicolaou, George N.

doi:10.1002/aja.1000400209

Cited by 23 publications

(13 citation statements)

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“…We believe that future studies could demonstrate the importance of this phenomenon, which was described in detail in early twentieth century by Stockard & Papanicolaou (1917) and Kelly & Papanicolaou (1927) in Cavia porcellus, but has been little detailed in other rodent species. To date, we believe that the development of the vaginal closure membrane in G. spixii is possible due to the presence of the external urethral ostium at the top of the clitoris (Santos et al 2014b) instead vaginal vestibule, which is absent in this species (Santos et al 2014a).…”

Section: Discussionmentioning

confidence: 45%

“…Regarding Caviidae as Cavia porcellus (Stockard & Papanicolaou 1917;Kelly & Papanicolaou 1927), C. aperea and G. musteloides (Touma et al 2001), the authors report that females show development of a vaginal closure membrane during the estrous cycle. This fact may be related to intraspecific sexual selection and formation of various mating systems among Caviidae (Adrian & Sachser 2011).…”

Section: Introductionmentioning

confidence: 41%

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Characterization of the estrous cycle in Galea spixii(Wagler, 1831)

et al. 2015

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RESUMO.-[Caracterização do ciclo estral de Galea spixii (Wagler, 1831).]Os Galea spixii habitam a vegetação semiá-rida da Caatinga, no Nordeste brasileiro. Eles são criados em cativeiro para realização de pesquisas relacionadas a biologia da reprodução. Sendo assim, o objetivo deste trabalho foi caracterizar o ciclo estral de G. spixii para obtenção de informações que melhorem o conhecimento do manejo reprodutivo da espécie em cativeiro. O ciclo estral foi monitorado por citologia esfoliativa vaginal em doze fêmeas adultas. Após a detecção de dois ciclos completos em cada animal, os mesmos foram eutanasiados. Em seguida foi realizado estudo histológico do epitélio vaginal com três fêmeas em cada fase do ciclo estral; cinco foram pareadas com machos para realização do grupo controle e outras três fêmeas foram utilizadas para monitorar a formação e ruptura da membrana de oclusão vaginal. Através de citologia esfoliativa vaginal, constatou-se predomínio de células superficiais em estro, células intermediárias grandes em proestro, células intermediárias pequenas e células parabasais com presença de neutrófilos em diestro e metaestro, respectivamente. O es- The Galea spixii inhabits semiarid vegetation of Caatinga in the Brazilian Northeast. They are bred in captivity for the development of researches on the biology of reproduction. Therefore, the aim of this study is characterize the estrous cycle of G. spixii, in order to provide information to a better knowledge of captive breeding of the species. The estrous cycle was monitored by vaginal exfoliative cytology in 12 adult females. After the detection of two complete cycles in each animal, the same were euthanized. Then, histological study of the vaginal epithelium, with three females in each phase of the estrous cycle was performed; five were paired with males for performing the control group for estrous cycle phases, and three other were used to monitor the formation and rupture of vaginal closure membrane. By vaginal exfoliative cytology, predominance of superficial cells in estrus, large intermediate cells in proestrus, intermediate and parabasal cells, with neutrophils, in diestrus and metestrus respectively was found. Estrus was detected by the presence of spermatozoa in the control group. By histology, greater proliferation of the vaginal epithelium in proestrus was observed. We conclude that the estrous cycle of G. spixii lasts 15.8 ± 1.4 days and that the vaginal closure membrane develops until complete occlusion of the vaginal ostium, breaking after few days. Future studies may reveal the importance of this fact for the reproductive success of this animal. INDEX TERMS: Galea spixii, cavies, female, preservation, reproduction, rodents. Characterization of the estrous cycle in

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Section: Discussionmentioning

confidence: 45%

Section: Introductionmentioning

confidence: 41%

Characterization of the estrous cycle in Galea spixii(Wagler, 1831)

et al. 2015

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“…In D. leporina , it is also worth highlighting the formation of a mucus plug and the consequent formation of the vaginal closure membrane in pregnant animals, as described in C. porcellus (Kelly & Papanicolaou, ; Stockard & Papanicolaou, ) and in G. spixii (Santos et al, ). Further studies are needed to elucidate the factors involved in the formation process of the mucus plug and vaginal closure membrane.…”

Section: Discussionmentioning

confidence: 96%

Morphology of the genital organs of the female red‐rumped agouti (Dasyprocta leporina, Linnaeus, 1758) during estrous cycle phases and in advanced pregnancy

Oliveira

Júnior

Sousa³

et al. 2019

Journal of Morphology

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The study investigated the gross and microscopic anatomy of the genital organs of 20 agoutis at different stages of the estrous cycle and four in the final trimester of pregnancy. Specimens were euthanized and their reproductive organs were fixed in a 4% paraformaldehyde or 2.5% glutaraldehyde solution and submitted to routine histological techniques for light and scanning electron microscopy. In the ovary, during the proestrus phase, we observed developing follicles and corpus luteum (CL) in regression; during estrus, there were Graafian follicles; during metestrus, there was a hemorrhagic corpus, whereas in diestrus, there was a mature CL. The uterus was partially double because the cervix was cranially septate but caudally, the septum disappeared, forming a single ostium that opened into the vagina. Changes occurred along the estrous cycle in the uterine and vaginal epithelia, that is, an increase in the uterine epithelium height accompanied by an increase of thickness of the vaginal epithelium during the follicular phase and a decrease of thickness of both epithelia during the luteal phase. The endometrial lining was composed of a simple cuboidal epithelium to simple columnar epithelium with basal nuclei. The vaginal mucosa consisted of epithelium that varied from nonkeratinized stratified squamous (luteal phase) to keratinized stratified squamous (follicular phase). The clitoris was external to the vagina. It presented two protruding lateral keratinized spicules and a centralized urethra, with no common parts between the urinary and genital tracts. Anatomical and histological changes were observed mainly in the cervix, vagina and spicules of the clitoris during the EC.

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“…A constituição desta membrana é muito variável podendo ser desde uma secreção mucosa até a formação de um tecido que fecha todo o orifício vaginal. Em Cavia porcellus, (Kelly & Papanicolaou, 1927) e Galea spixii (Santos et al 2014), esta membrana de oclusão vaginal é descrita como sendo de origem epitelial. De modo geral, entende-se ser difícil a extrapolação de técnicas e conceitos aplicáveis às diferentes espécies, haja vista existirem roedores que apresentam comportamento de estro e ruptura da membrana de oclusão vaginal somente com indução da presença do macho, enquanto outras espécies apresentam estro espontâneo (Touma et al, 2001).…”

Section: Discussionunclassified

Monitoramento do ciclo estral de cutias (Dasyprocta leporina Lichtenstein, 1823) através de citologia esfoliativa vaginal e ultrassonografia

et al. 2015

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RESUMO.-O objetivo deste estudo foi monitorar o ciclo estral em cutias (Dasyprocta leporina) criadas em cativeiro no semiárido brasileiro. Durante 70 dias, cinco cutias foram diariamente submetidas a citologia esfoliativa vaginal, e o monitoramento ultrassonográfico ovariano foi realizado a cada três dias. Um total de 8 ciclos estrais foi completamente monitorado, com duração de 28,2±0,7 dias, variando de 24 a 31 dias. Pela citologia esfoliativa vaginal, houve uma predominância de células superficiais nas fases de proestro e estro (P<0,05), seguida da predominância de células intermediárias no metaestro (P<0,05) e de células parabasais no diestro (P<0,05). Por ultrassonografia, não houve diferenças na morfologia ovariana durante as diferentes fases do ciclo estral (P>0,05). Os folículos foram identificados durante as fases estrogênicas (proestro e estro), com diâ-metro médio de 1±0,5mm. Em apenas 12,5% das fases luteais, corpos lúteos medindo 1,4±0,9mm foram identificados. Conclui-se que a associação da citologia vaginal e da ultrassonografia ovariana constitui uma alternativa viável para o monitoramento de ciclos estrais e identificação das fases estrogênicas em cutias da espécie Dasyprocta leporina. TERMOS DE INDEXAÇÃO:Dasyprocta leporina, roedores, colpocitologia, ecografia ovariana. INTRODUÇÃOAs cutias (Dasyprocta sp.) são roedores utilizadas frequentemente como fonte de alimento e extração de sua pele, couro e pelos por populações humanas (Lopes et al. 2004 The objective of the study was to monitor the estrous cycle in agoutis (Dasyprocta leporina) bred in captivity in Brazilian semiarid. During 70 days, five agoutis were daily subjected to vaginal exfoliative cytology, and the ovarian ultrasound monitoring was conducted every three days. A total of 8 estrous cycles were completely monitored, lasting 28.2±0.7 days, ranging from 24 to 31 days. By vaginal exfoliative cytology, there was predominance of superficial cells at proestrus and estrus phases (P<0.05), followed by the predominance of intermediate cells in the metestrus (P<0.05) and parabasal cells in diestrus (P<0.05). By ultrasound, there were no differences in ovarian morphology during the different phases of the estrous cycle (P>0.05). Follicles during the estrogenic phases (proestrus and estrus) were identified, with an average diameter of 1±0.5mm. In only 12.5% of luteal phases, corpora lutea measuring 1.4±0.9mm were identified. We conclude that the association of vaginal cytology and ovarian ultrasonography is a useful alternative for monitoring the estrous cycle and identifying the estrogenic phases in Dasyprocta leporina.INDEX TERMS: Dasyprocta leporina, rodents, colpocytology, ovarian echography.

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The mechanism of the periodical opening and closing of the vaginal orifice in the guinea‐pig

Cited by 23 publications

References 6 publications

Characterization of the estrous cycle in Galea spixii(Wagler, 1831)

Characterization of the estrous cycle in Galea spixii(Wagler, 1831)

Morphology of the genital organs of the female red‐rumped agouti (Dasyprocta leporina, Linnaeus, 1758) during estrous cycle phases and in advanced pregnancy

Monitoramento do ciclo estral de cutias (Dasyprocta leporina Lichtenstein, 1823) através de citologia esfoliativa vaginal e ultrassonografia

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