Results of experimental investigations of the power put by a power supply unit of metal vapor lasers in a commutator and a gas-discharge tube (GDT) are presented. Simple relations are derived that can be used to calculate the plasma capacitance of the commutator and GDT caused by space charges due to plasma polarization as well as the amplitude-temporal parameters of a gas-discharge pulse. The existence of the Pashen pulse-frequency responses (PPFRs) for a periodic-pulse discharge is identified. They are functions of the pulse repetition frequency and the rate of the voltage increase on a gas-discharge gap with all other parameters remaining the same. The enhanced pump power density is found experimentally in the near-electrode zones of the GDT together with the temperature gradient between the electrodes. The latter depends on the gas pressure, voltage, and other parameters.