diff --git a/neuron/presynapse.md b/neuron/presynapse.md
index 590f32c..b8a14da 100644
--- a/neuron/presynapse.md
+++ b/neuron/presynapse.md
@@ -100,6 +100,9 @@ VGCC-PRE-TUN
   TryTunUpPreVcgg_ctx
     sec
       PossibleUpPreVgccTun: ( active: 10x )
+      
+  TryTunDownPreVcgg_ctx
+    sec
       PossibleDownPreVgccTun: ( active: 10x )
 ```