title: The effect of the suckling stimulus on the migration of Strongyloides ratti in lactating rats.
abstract: The number of adult Strongyloides ratti which developed in the guts of lactating rats after subcutaneous injection of 4000 L3 on day 18--20 post partum was taken to be a measure of the relative importance of alternative larval routes. When injection was carried out at different times before and after weaning, larvae were diverted from a route bypassing the gut in nursing mothers to one leading to the gut ("migration reversal") in mothers without young in a period of less than 10 h. Migration reversal was mostly completed in lactating females injected at the time of weaning when compared with nulliparous controls. A stimulus-sensitive period shortly after injection, predicted from these dynamics, was demonstrated. Worms injected into lactating females 10 h after removal from their pups showed complete migration reversal. In similarly treated rats, given 1 h suckling 3 h after injection, migration reversal was practically abolished. These inter-relationships, in conjunction with earlier findings, are used to deduce the possible humoral mechanisms involved and to develop a working hypothesis to account for larval orientation based on features of the mammalian pulmonary microvasculature.
mesh_terms: D000818:Animals; D004064:Digestive System / Q000469:parasitology; D005260:Female; D007774:Lactation; D008168:Lung / Q000469:parasitology; D051379:Mice; D009068:Movement; D011247:Pregnancy; D013321:Strongyloides / Q000502:physiology*