I have no idea what z hell iz going on...:). SeriouZly, if you want help, you need to explain what you mean by CV experiment? I can guess but I might be wrong. Are you doing paired-pulse ratio (PPR)? and determining the coefficient of variation (CV)? If you have formation of bubbles at the stimulation point...well it could mean that you are frying your slice. try to stimulate with less Zealous voltage. I hope I am making you smile, because you did make me smile with your zzzz everywhere!!

@ Fouad Lemtiri-Chlieh

I have been running Cyclic Voltammetry (CV) experiment using Bipotentiostat 760D  advanced electrochemical workstations and discovered the formation of bubbles at my Glassy carbon Working Electrode & evolution of gas at the Pt counter electrode since last week. I have changed my Reference Electrode(RE) and it worked for two days and the same thing has happened with new RE. So I couldn't able to run my work. what will be the possible reason and solution, please?

Thank you Birhanu for your explanation. I can see now what you meant by CV experiment. Unfortunately, I can't help you much but at least I helped you to formulate your question better and I am sure someone might answer your query. Good luck with your experiments.

It may be that you applied the potential out of the range of stability of the solvent or whatever you have in the cell. You need to verify if the range of potentials applied correspond to the stability range of the components in the electrolyte. 

If in the range of applied potentials no gas evolution is expected, then you have a problem of potential control. Before running CV make sure that the contacts with all electrodes are fine. For example, check if an open circuit potential of WE is stable. If it is fluctuating too much, this is an indication of poor contact with either WE or RE. To detect the problem, check also the contact between CE and RE. In fact, if contact with RE is unstable, then potentiostat may apply the maximal appliance voltage between WE and CE, and you may observe gas evolution on both electrodes. 

what's your potential range?

If you have a suitable potential for the solution you are testing, and you have tried Sergeys suggestions, I have seen this issue before with a damaged/defective op-amp in the potentiostat. This can be especially true if the room is dry and the instrument isn't properly protected. First check for simpler things like connection issues or bubbles in the reference electrode.