<i>Hymenolepis diminuta</i>: the role of the tail in determining the position of the worm in the intestine of the rat

Hopkins, C. A.; Allen, Laura

doi:10.1017/s0031182000053798

Cited by 17 publications

(5 citation statements)

References 14 publications

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“…A localização de helmintos no intestino delgado de seus hospedeiros vertebrados é determinada pela interação entre certos estímulos do ambiente intestinal e a habilidade do helminto em interpretar e monitorar essas condições, no sentido de se mover em direção a uma posição favorável no intestino delgado ALLEN, 1979). Os resultados obtidos no presente estudo sugerem que a DMS tenha exercido influência também sobre a distribuição de R. nana em M. unguiculatus.…”

Section: Discussionunclassified

Desenvolvimento e distribuição de Rodentolepis nana em Meriones unguiculatus

Vianna¹,

Melo²

2008

cmbio

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Com o objetivo de avaliar o desenvolvimento e a distribuição de Rodentolepis nana em Meriones unguiculatus, vinte animais receberam um inóculo oral de 100 ovos do parasito. A metade desses roedores recebeu, por via subcutânea, inóculo diário de dexametasona (DMS) (10mg/Kg). Aos 7 e 15 dias após a infecção (DPI), cinco animais de cada grupo foram sacrificados para a recuperação dos parasitos. Em M. unguiculatus não tratados, foram recuperados parasitos somente no 7o DPI, em início de maturação e distribuídos principalmente pela porção distal do intestino delgado desse roedor. Nesta mesma data, os parasitos recuperados em M. unguiculatus, que receberam DMS, estavam possivelmente no mesmo estádio que os encontrados em M. unguiculatus não tratados, porém distribuídos pelas porções média e distal do intestino delgado. Aos 15 DPI, os helmintos recuperados em M. unguiculatus que receberam DMS estavam completamente desenvolvidos, apresentando proglotes maduras e grávidas, distribuídos principalmente pela porção média, e, secundariamente, pela porção distal do intestino delgado. Conclui-se que M. unguiculatus tem reduzido potencial como reservatório deste cestóide e sua resistência à infecção pelo R. nana tem um importante componente inflamatório, sensível à ação da DMS.

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Section: Discussionunclassified

Desenvolvimento e distribuição de Rodentolepis nana em Meriones unguiculatus

Vianna¹,

Melo²

2008

cmbio

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“…Normally, in fasted rats, the scoleces are situated anterior to segment 7, so that we may assume that gastric secretions re-routed to segments 6-8 would be acting on the mid-or posterior regions of the worm strobila. The concept of specific regions of the worm being important in migrational behaviour (Hopkins, 1970;Hopkins & Allen, 1979;Roberts, 1982) is supported by the differences in the behavioural responses shown by H. diminuta.…”

Section: Discussionmentioning

confidence: 99%

Migrational responses of Hymenolepis diminuta to surgical alteration of gastro-intestinal secretions

Sukhdeo

Mettrick

1984

Parasitology

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The effects of the direction of gut flow, of injections of glucose and saline into different regions of the small intestine and of surgical re-routing or ligature of gastric, biliary and pancreatic secretions into the small intestine have been correlated with changes in the migratory response of the rat tapeworm Hymenolepis diminuta. Reversing the normal anterior to distal flow of luminal contents in the small intestine did not affect worm migration following feeding. Injections of a glucose-saline solution into the duodenum did not initiate a migratory response; similar injections into the mid- and posterior regions of the small intestine resulted in migrational responses similar to those following intragastric glucose feeding. Re-routing gastric secretions to the distal duodenum inhibited anterior migration of the worms beyond the new point of entry of gastric juices. Results following re-routing and ligation of the biliary and pancreatic secretions suggest that there is a potent cue to anteriad migration in the pancreatic secretions. Biliary secretions also appear to contain an additional migratory cue to worm migration. In order of importance the factors stimulating/inhibiting worm migration are pancreatic greater than gastric greater than biliary greater than glucose. The results support the hypothesis that the factors affecting worm distribution in the small intestine are interactive and synergistic, involve other luminal factors, such as 5-hydroxytryptamine and the physico-chemical gradients, and are of a regional nature such that the migratory response of a particular worm is directly related to its position in the small intestine when the cues to relocation are received.

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“…The cause of this decrease in maturation rate is unclear. Possible factors affecting the maturation rate include the changes in biochemical composition in proglottids that are even of comparable stages of maturation (Mettrick & Cannon, 1970), the difference in micro-environment along the length of the worm as suggested by the migration of worms in the intestine (Hopkins & Allen, 1979) and the changes in the activity of the rostellar gland cells (Davey & Breckenridge, 1967). The remarkable increase in size of the proglottid during the early development might also affect the maturation rate.…”

Section: Discussionmentioning

confidence: 99%

Kinetics of proglottid formation, maturation and shedding during development of Hymenolepis nana

Kumazawa¹,

Suzuki²

1983

Parasitology

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Growth of Hymenolepis nana in mice is analysed by identifying designated stages of proglottid maturation in the strobila, and by determining the numbers of proglottids between them and the posterior terminus of the worm, as a function of time after cysticercoid infection. The proglottid maturation rate was fairly constant between stage A (onset of the somatic primordium formation) and stage B (first appearance of sperms in the seminal vesicle), but gradually fell after stage B, during pre-patent development of the worm. The actual rate of proglottization during this period coincided well with that estimated from the number of proglottids between stages A and B on an assumption of a certain maturation rate. This procedure is extended to estimate the rates of proglottid formation and shedding during later development. It is deduced that the absolute rate of proglottization increases until day 12, gradually decreasing afterwards, and that from 2300 to 2800 proglottids are shed by day 20, until which from 4000 to 4500 proglottids have passed stage A. It is shown that the proportionate increase of the gravid region in older worms depends not only on a decrease in the rate of proglottization, but also on the prolonged period during which proglottids stay in the strobila.

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Hymenolepis diminuta: the role of the tail in determining the position of the worm in the intestine of the rat

Cited by 17 publications

References 14 publications

Desenvolvimento e distribuição de Rodentolepis nana em Meriones unguiculatus

Desenvolvimento e distribuição de Rodentolepis nana em Meriones unguiculatus

Migrational responses of Hymenolepis diminuta to surgical alteration of gastro-intestinal secretions

Kinetics of proglottid formation, maturation and shedding during development of Hymenolepis nana

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