diff --git a/bkpkj.mod b/bkpkj.mod
index 3502291..4ed5102 100644
--- a/bkpkj.mod
+++ b/bkpkj.mod
@@ -8,7 +8,7 @@ NEURON {
        RANGE gkbar
        GLOBAL minf, mtau, hinf, htau, zinf, ztau
        GLOBAL m_vh, m_k, mtau_y0, mtau_vh1, mtau_vh2, mtau_k1, mtau_k2
-       GLOBAL z_coef, ztau
+       GLOBAL z_coef
        GLOBAL h_y0, h_vh, h_k, htau_y0, htau_vh1, htau_vh2, htau_k1, htau_k2
 }