Pharmacological evidence for cell surface control of oral regeneration in Stentor coeruleus

Abstract

This study suggests that membrane perturbations can affect oral morphogenesis in Stentor, possibly by a mechanism involving calcium ions. Exposure of regenerating Stentor to micromolar concentrations of the membrane active local anesthetics dibucaine, tetracaine, or procaine greatly delayed the progress of oral regeneration. In the case of tetracaine and dibucaine the greatest delays were observed in the early stages of regeneration prior to stage 4, when the majority of essential synthetic activity is occurring. The effects of dibucaine were generally readily reversible upon removal of the cells from the drug, with some residual effects occurring at higher dibucaine concentrations. Regenerating cells in the presence of dibucaine and excess extracellular calcium were not delayed, suggesting that the effects of dibucaine were reversible by calcium ions. The effects of tetracaine were not reversible by calcium ions, however. Exposure of regenerating cells to medium either lacking in, or containing an excess of, extracellular calcium had no effect on the time required to complete oral regeneration. The plant lectin, phytohemagglutinin, can also delay oral regeneration. The possible implications of these findings on the control of oral regeneration are discussed.

Concanavalin a inhibits oral regeneration in Stentor coeruleus through a mechanism involving binding to the cell surface

“…Other membrane active agents, including PHA (Maloney, 1980(Maloney, , 1984 seem to delay oral regeneration primarily in the early stages of oral regeneration. If one examines the time necessary for cells to pass through one stage of oral regeneration and into the next, one obtains the data shown in Figure 1.…”

“…Thus her results have clearly demonstrated the involvement of the cell surface in the control of oral development. Pharmacological experiments using various chemical membrane probes have confirmed this hypothesis by indicating that various membrane perturbations can also affect oral development (Maloney, 1980(Maloney, , 1984. The actual means by which the cell surface regulates oral development is uncertain, though one possible mechanism could involve glycosylated membrane proteins.…”