Voltage-Dependent Calcium Channels in Merkel Cells of Hamster Oral Mucosa

Summary

Previous studies have demonstrated the existence of voltage-dependent Ca²⁺ channels in the membrane of Merkel cells. In order to investigate which categories of Ca²⁺ channels are involved, we examined the changes in the fluorescence ratio of single isolated Merkel cells loaded with fura-2 during 334/380 nm excitation. Cells were depolarized with a solution of high KC1 concentration (100 mM) known to open voltage-dependent Ca²⁺ channels. A transient increase in the fura- 2 334/380 nm excitation ratio which occurred in Merkel cells was induced by 100 mM KC1. The results suggest that voltage-dependent L-type, N-type and P/Q- type Ca²⁺ channels exist in most Merkel cells. However, the number of voltage-dependent N-type Ca²⁺ channels in Merkel cells appears to be smaller or variable in comparison with the other types of Ca²⁺ channels.