Neurosecretory System in Earthworms - A Less Studied Research Area in Invertebrates | Chapter 5 | Research Aspects in Biological Science Vol. 5

Between 1928 and 1937, Berta and Ernst Scharrer (1906-1995) explored the idea of neurosecretion for the first time. The neurosecretory cell, which resembles a "tear drop," is both glandular and neuronal in form. It is consistent with the ultrastructure of the cells that the neurosecretory products (neurosecretion/neurohormone) are proteinaceous in nature. Normally, neurosecretory substances are discharged into the blood capillaries by way of an axon.

Regardless of their ecological classifications, the location, structure, and activities of neurosecretory cells in the central nervous systems of various earthworm species are more or less the same. The central nervous system of tropical earthworms exhibits two primary types of neurosecretory cells: deeply stained A type cells (deeply stained AF positive cells with characteristic axonal processes in the outer cortical tier) and lightly stained B type cells (lying in between A type cells and central fibrous neuropile). Neural lamella and epineurium surround the neurosecretory cells of the central nervous system on all sides. The central nervous system's "medulla" is made up of vascularized and fibrous neuropile. At the base of the circumesophageal connectives of the subesophageal ganglia, there are S cells or Hubl cells in addition to A and B cells, which make up a "islet" of neurosecretory cells. At the "zone of accumulation," a highly vascularized fibrous neuropile that can be considered a "elementary neuro-haemal organ," both A and B cells release (neurohormone). In Oligochaetes, neurosecretion affects a variety of processes including feeding, osmoregulation, thermal acclimatisation, regeneration, copulation, cocoon formation, and oogenesis.

 

Author (s) Details

Priyasankar Chaudhuri

Earthworm Research Laboratory, Department of Zoology, Tripura University (A central University), Suryamaninagar-799022, Tripura West, India.

 

View Book :-  https://stm.bookpi.org/RABS-V5/article/view/7614

Studies on the effects of Posterior Amputation on the Cerebral Neurosecretory Cells of Indian Earthworm, Lampito mauritii (Kinberg) | Chapter 16 | New Frontiers in Medicine and Medical Research Vol. 11

 Because earthworms are vulnerable to predator assaults and agricultural activities, nature has endowed them with the ability to regenerate destroyed body segments. In the lack of a defined nonneural endocrine gland, the cerebral neurosecretory system is likely to play a key role in wound healing and body segment regeneration.

The purpose of this research is to look at the cytomorphological changes in the cerebral neurosecretory cells after amputation in the topsoil Indian earthworm Lampito mauritii.

Dissected cerebral ganglia were fixed in Bouin's solution and processed for traditional neurosecretory staining techniques: Paraldehyde Fuchsin (AF) and Chrome Alum Haematoxylin Phloxin after posterior amputation of the earthworm with a paragon knife (CAHP).

Following transection of 10 posteriormost body segments, a wave of muscle contraction was observed along the anteroposterior direction of Lampito mauritii's body.

Following posterior amputation of body segments, cerebral neurosecretory cells (especially the AF+ve A cells) showed changes in secretory dynamics, in contrast to control. Due to the depletion of neurosecretory resources, the number of AF+ve A cells decreased during wound healing after 24 hours. The formation of regeneration blastema was followed by an increase in the number of AF+ve strongly pigmented A neurosecretory cells 48 to 72 hours after amputation. Coarse secretory granules were also seen in the moderately stained B cells. After 48 to 72 hours of amputation, axonal transport and a 'zone of accumulation' charged with AF+ve neurosecretion were also seen.

Conclusion: In the earthworm Lampito mauritii, cerebral neurosecretory cells are involved in wound healing and subsequent regeneration, according to our preliminary findings.

Author(S) Details

Anurag Bhattacharjee
Department of Zoology, Tripura University, India.

P. S. Chaudhuri
Department of Zoology, Earthworm Research Laboratory, Tripura University, Suryamaninagar-799022, Tripura, India.

View Book:- https://stm.bookpi.org/NFMMR-V11/article/view/3702