When watching television it is not uncommon to see an add for this or that product which blocks allergies or increases dopamine release and from this information one can conclude what the product could be used for. The field of neuroscience is no different, substances are given a name and when testing them its function is determined. Take the any ion channel in the body for example, a substance that increases its function is called an opener and a substance that reduces its function is called a blocker.
A substance that increases an enzymes function is called an opener, that's straight forward right? Now imagine you just get done taking a run and you have a cup with a lid and straw that is a quarter full of water (remember you are thirsty and have to optimize what you have!). You would want to get the most water out of the cup as possible, so maybe you take and lid off and remove the straw between the water and you, maybe you get a bigger straw so you can drink the water quicker, or maybe you could cloud seed the entire sky and have all the water you could want. The first two examples play by the rules, the second just changes the environment.
This is often the case with openers and blockers, they often work by affecting the environment around the cell. Take Retigabine for example, this Kv7 potassium channel opener that it works by inhibiting higher membrane potentials (that does sound like it opens the channel any).
In a recent research paper I did I found a number of examples like this, which I just found humorous, see scientists can be just and silly and illogical as everyone else!