The role of sodium influx via voltage-gated sodium channels in regeneration of Lumbriculus variegatus
Graduation Date
2015
Document Type
Thesis
Program
Other
Program
Thesis (M.S.)--Humboldt State University, Biology, 2015
Committee Chair Name
Bruce A. O'Gara
Committee Chair Affiliation
HSU Faculty or Staff
Keywords
Humboldt State University -- Theses -- Biology, Cell division
Abstract
The California Blackworm (Lumbriculus variegatus) has great ability to regenerate from small fragments into a new worm depending on two forms of regeneration: epimorphosis and morphallaxis. Both patterns of regeneration work in concert with each other in order to ensure the survival of the organism. Regeneration of the head segments following amputation produces 7-8 new segments; while the number of regenerated tail segments is dependent on the time following amputation. The nature, origin, and position of cells that are involved in formation of new tissues during regeneration in L. variegatus for both head and tail regeneration are not completely known. In this study I'm trying to find the nature, origin, and position of the neoblasts and investigate if the neoblasts that migrate into the cut site are cells derived from differentiated tissues already in the region of the wound by using EdU staining. The results showed that stem cells (neoblasts) are randomly scattered in the body and few in number. Upon injury these cells undergo hyperproliferation and migrate to the wound site for both head and tail regeneration. During head regeneration the results suggested a reprogramming of cells in the cut site upon injury due to the abundance of Na+ in cells in the injury site. Recent studies showed that a change in the cell's resting potential influences regeneration. In this study, I exposed the worms to the voltage-gated sodium channel blocker tricaine (TMS) and examined somatic regeneration of heads and tails following body transection. Regeneration of worms was examined for 10 days after amputation either in the presence of TMS or in control pond water. Regeneration of both new head and tail body segments was reduced in the presence of TMS, especially in the tail. Head regeneration in the presence of TMS showed defective morphology with no well defined segments. Both effects of sodium transport into the cells in the bud region were examined by CoroNa Green staining, and somatic cell regeneration in the bud by EdU. The number of dividing cells in the bud region for both head and tail TMS-treated worms decreased significantly, although number of dividing cells that were scattered around the remainder of the body didn't show a significant change compared to control worms. The number of proliferating cells in the bud region showed a strong relationship with the concentration of Na+ in the cells in the bud region. To further investigate the effects of sodium influx on regeneration, monensin, a sodium ionophore, was used in TMS-treated worms. These worms did not show increased regeneration ability compared to TMS-treated worms. In combination, these result suggest that sodium influx via voltage-gated sodium channels has effects on both head and tail regeneration that affects cell migration of dividing cells that are scattered around the body and dividing cells in the bud region.
Recommended Citation
Alkhathlan, Manal, "The role of sodium influx via voltage-gated sodium channels in regeneration of Lumbriculus variegatus" (2015). Cal Poly Humboldt theses and projects. 1833.
https://digitalcommons.humboldt.edu/etd/1833
https://scholarworks.calstate.edu/concern/theses/j098zd368