[Zope] Accessing ZSQL connection from external method

Howdy! I'm making heavy use of MySQLdb in my external methods. Now I just realized that ZSQL-connections are kept open permanently and it would save a lot of time if I wouldn't have to open a connection each time my external method is invoked but use the already existing ZSQL-connection instead. My question: How can I access a ZSQL-connection (ZMySQLDA) from an external method? --Ragnar P.S.: I benchmarked MySQLdb and found that opening a connection took 1.2ms on my systen whereas a very short request for authentication took only 1.1ms. So beeing able to use an existing connection would result in about 100% performance gain (at least at first glance).