diff --git a/elements/neuron/presynapse.md b/elements/neuron/presynapse.md
index 2abf488..32d36bc 100644
--- a/elements/neuron/presynapse.md
+++ b/elements/neuron/presynapse.md
@@ -70,7 +70,7 @@ PRESYNAPSE
 
       // Tub
     _NT: INTRICATE [ tub: &ASTROSYNAPSE._NT ] 
-    _ATP: INTRICATE [ tub: &ASTROCYTE._ATP ] 
+    _pre_budget: INTRICATE [ tub: &ASTROCYTE._pre_budget ] 
     _eCB: INTRICATE [ tub: &POSTSYNAPSE._eCB ]
 
     // Instantiation
@@ -115,23 +115,31 @@ MAIN
 
   // Emit NT
   
-    void: INSTANTIATE [ accumulator: NTreleaseLow, event: 12x, cost: 3x, context: *AP ] {
-      hypothesis: _Ca2 mediumness AND _Rrp mediumness AND NOT _ATP empty 
-        action: [ _Rrp decrease, _NT increase, _ATP decrease ]
-        trace: None
-    }
-    
-    void: INSTANTIATE [ accumulator: NTreleaseMedium, event: 9x, cost: 3x, context: *AP ] {
-      hypothesis: ( _Ca2 fullness AND _Rrp mediumness ) OR ( _Ca2 mediumness AND _Rrp fullness ) AND NOT _ATP empty 
-        action: [ _Rrp decrease, _NT increase, _ATP decrease ]
-        trace: None
-    }
+  void: INSTANTIATE [ accumulator: NTreleaseLow, event: 12x, cost: 3x, context: *AP ] {
+    hypothesis: _Ca2 mediumness AND _Rrp mediumness AND NOT _pre_budget empty 
+      action: [ _Rrp decrease, _NT increase, _pre_budget decrease ]
+      trace: None
+  }
+  
+  void: INSTANTIATE [ accumulator: NTreleaseMedium, event: 9x, cost: 3x, context: *AP ] {
+    hypothesis: ( _Ca2 fullness AND _Rrp mediumness ) OR ( _Ca2 mediumness AND _Rrp fullness ) AND NOT _pre_budget empty 
+      action: [ _Rrp decrease, _NT increase, _pre_budget decrease ]
+      trace: None
+  }
 
-    void: INSTANTIATE [ accumulator: NTreleaseHigh, event: 6x, cost: 3x, context: *AP ] {
-      hypothesis: _Ca2 fullness AND _Rrp fullness  AND NOT _ATP empty
-        action: [ _Rrp decrease, NT increase, _ATP decrease ]
-        trace: None
-    }
+  void: INSTANTIATE [ accumulator: NTreleaseHigh, event: 6x, cost: 3x, context: *AP ] {
+    hypothesis: _Ca2 fullness AND _Rrp fullness  AND NOT _pre_budget empty
+      action: [ _Rrp decrease, NT increase, _pre_budget decrease ]
+      trace: None
+  }
+
+  // Tag endourance
+
+  void: INSTANTIATE [ accumulator: endourance_tag, event: 12x, cost: 3x, context: *AP ] {
+    hypothesis: _pre_budget empty AND other signals 
+      action: [ _pre_endurance_tag increase ]
+      trace: None
+  }  
 
 ```