[1] Asahi Univ, Sch Dent, Div Oral Struct Funct & Dev, Dept Oral Ant, Gifu 5010296, Japan
[2] Gifu Univ, Sch Med, Dept Physiol, Gifu 500, Japan
[3] Gifu Univ, Sch Med, Dept Anat & Neurosci, Gifu 500, Japan
[4] Kanagawa Dent Coll, Dept Physiol & Neurosci, Yokosuka, Kanagawa 238, Japan