Coming back down from SendMessageUpwards

I have a script that uses the send message upwards function to apply damage using this line:

 Hit.collider.SendMessageUpwards("ApplyDamage", Damage, SendMessageOptions.DontRequireReceiver);

How can I find variables in the script that holds this function? The script that the damage is applied to has access to the enemies overall health and I need to access it through this script. Any ideas?