Slade told the club website: "I can confirm I was not given permission to speak to them and this brings with it an element of frustration.
"I remain fully committed to my job at Leyton Orient."
Barnsley approached Slade last week about the vacant manager's position at Oakwell, and the O's boss admitted he would have considered the chance to work at the Yorkshire club.
We all understand Russell's ambition and indeed we want all our contracted players and management to be ambitious to perform at a higher level
Chairman Barry Hearn
"I firmly believe that any ambitious football manager, player or non-football related employee anywhere in the country would have liked the chance to consider the opportunity to instantly work at a higher level," he said.
"The last manager at Orient to have been given that opportunity was Jimmy Bloomfield in 1971, so that highlights how infrequently these opportunities come along.
"That being said, I am a professional and pride myself in having never walked out on a football club."
The former Yeovil boss, who arrived at Brisbane Road in April 2010, added: "I am looking forward to working with the team to achieve another successful season."
Orient finished the League One season one point off a play-off position in seventh place, and Hearn said the club were eager to build on the success next term.
"We all understand Russell's ambition and indeed we want all our contracted players and management to be ambitious to perform at a higher level," said the O's chairman.
"The board, staff and fans share that ambition for a brighter future in a difficult environment and will continue to support Leyton Orient in its efforts to achieve future success."
Source: BBC Sport