Neurosecretory Phenomena during Reproduction in Oligochaeta

Cytology and Histology of the Cerebral Neurosecretory Systems in some Tropical Earthworm Species

“…Classification of NSCs in the cerebral ganglion of earthworms has been made chiefly on the basis of cytomorphological characteristics, their distribution and staining characteristics [12,[21][22][23][24][25][26][27][28]. Some of these observations agree with one another but many others differ.…”

“…Earlier, Teichmann et al [29] have classified A-cells into A1-, A2-and A3-cells in the cerebral ganglia of Lumbricus herculeus and Eisenia fetida on the basis of histochemical characteristics. According to Herlant-Meewis [7] type A1-and A2 cells are possibly the source of somatotrophic and gonadotrophic hormone respectively. Absence of secretory cycle in A1 cells under adult condition indicates that these cells probably remain active during growth phase of the earthworm.…”

“…According to Scharrer and Scharrer [5], almost one half of the cerebral ganglia in oligochaetes is glandular. In fact NSCs within the CNS of earthworms are regarded as the source of "vascular" hormones controlling many biological activities such as growth, osmoregulation [6], reproduction [7][8][9], thermal acclimation [10], food intake [11], regeneration [12,13] and light reaction [14]. In absence of any definite neurohaemal organ, as found in polychaetes and arthropods [15,16], the neurosecretory system in oligochaetes deserve special attention because of being the first class of coelomates with closed vascular system.…”