Dont take the risk man, most guitar amps cannot handle lows coming from the bass and can damage the speaker cone. I experienced it before, the amp is still working but the sound coming from the speaker cone is not anymore the same.
no never do that! a guitar amp is designed soley for guitars only. using the electric bass will cause some exceeding in the voltage or dunno what lah then will cause the amp to blow. this has been discussed before i think. just dont take the risk.