Calling a function without input arguments in Matlab gui

I am new to Matlab, I want to call a function in different GUI without sending any arguments( from one GUI to another GUI).

Example:

gui1.m (in GUIDE)

function some_ui_OpeningFun(hObject, eventdata, handles, varargin)

a = 10;
setappdata(0,'a',a);

gui2('pushbutton1_Callback'...) %<- to call the function in the second gui

handles.output = hObject;

guidata(hObject, handles);

gui2.m (in GUIDE)

function pushbutton1_Callback(hObject, eventdata, handles)

b = getappdata(0,'a');
disp(a);

so i want to call the function pushbutton1_Callback from gui2.m.

I have tried using gui2('pushbutton1_callback',handles,.....) which was give in the GUID comments. But could't get it.

Can anyone tell me how to do so?

thanks in advance.