Hi Lurkingforacure,
The inhaler you describe is not for the nose, where there is a direct connection to the brain. It is an oral inhaler and the drugs go into the lungs then bloodstream. Since they go into the bloodstream it is similar to taking drugs by mouth.
Girija is right about the difficulty of formulating dopamine into a nasal (not mouth) spray.It could damage the delicate nose lining, with repeated use. It would be interesting to try a single experiment though, to confirm it works.
Ron
PS Did you read my reply to your question in the virus thread?