The role of chloride in mediation of the steady-state current in Limulus ventral photoreceptors
This thesis is an investigation of the voltage-gated, steady-state currents in the ventral visual organ of Limulus polyphemus. Specifically, studies have been undertaken to determine if chloride ions mediate any fraction of the steady-state currents observed in these cells. Evidence presented herein suggests that this steady-state current may be dependent upon the chloride levels surrounding the cell. This dependence appears to be inverse in nature over the external chloride concentrations studied. This observation holds true when potassium channel blockers TEA and 4-AP are applied to the preparation, as well as when they are not. A conductance model for chloride based on the Constant Field Theory fails to explain this inverse relationship. Additionally, experiments are included which suggest that the use of zero chloride experimental baths be avoided.