Feasibility is analyzed of sustaining steady-state or quasi-steady-state inversion of population of resonant and metastable levels in metal atoms due to collisional depopulation of the metastable level by heavy particles under gas-discharge excitation of the active medium. Criteria are formulated which make it possible to distinguish between self-terminating and quasi-CW emission modes in pulsed metal-vapor lasers. It has been found that discharge parameters required for obtaining the collisional laser action cannot be achieved under real conditions in the case of the high-pressure discharge. Numerical calculations for low-pressure discharge conditions show that the collisional depopulation of metastable levels in metal atoms is unable in most cases to provide for sustaining the steady-state population inversion.