Effects of dehydration and subsequent hydration stress on the cerebral neurosecretory cells of Eudrilus eugeniae (Kinberg, 1867)

Moisture is a limiting factor for the survival and distribution of earthworms. During rainy season earthworms come out from their water-filled burrows and during summer move deeper into the soil to prevent acute desiccational water loss. Moisture loving worms like Eudrilus eugeniae when subjected to the dry soil and then subsequently hydrated, both the types of neurosecretory cells (A and B cells) show contrasting neurosecretory changes. During dehydration stress (2, 4 & 6 hours), both A and B cells deplete, lose their cellular conformity with extensive vacuolation. But in subsequent hydration of desiccated worms for 4 hrs, there is accumulation of neurosecretory materials in both types of cells, chiefly in A cells. The result indicates involvement of both A and B neurosecretory cells during osmotic stress from the perspective of histomorphic variations and secretory dynamics.