[fw-mvc] Performance boost for ajax request?

Hello everybody, Sometimes there are requests that are simple ajax request (for example, get a district list of a city), that does not need to go through all the bootstrap and heavy stuff from Zend. Only a few Zend components such as : Zend_Session, Zend_Db then are needed. What is the best way to write the Action Controller for those requests? I haven't found Zend's support for that? Or am i missing something? Thanks