With the defeat of Sen. Howard M. Cannon (D-Nev.), the regulatory reform movement has lost one of its chief architects.

As the former chairman of the Senate Commerce Committee, the 70-year-old senator played a crucial role in getting Congress to deregulate the airline and trucking industries as well as relax government controls on the railroad industry.

Additionally, in his current role as ranking minority member of the committee, Cannon has helped the committee chairman, Sen. Bob Packwood (R-Ore)., keep pressure on the Interstate Commerce Commission to loosen its grip over the trucking industry to allow new firms to compete with companies long established in the industry.

Cannon also backed Packwood in most of the chairman's moves to remove federal regulation over the telecommunications and broadcasting industry.

"We've definitely lost one vote," an aide to Packwood said yesterday, in commenting on Cannon's loss. However, the aide added, he still believed Packwood had enough votes to get most of his deregulation proposals through his committee.

Even so, Cannon's departure could well affect the outcome of many of the issues the committee considers, particularly if Sen. Daniel Inouye (D-Hawaii) assumes the post of ranking minority leader as committee members are now speculating. Inouye is regarded as less of a deregulator and consumer supporter than Cannon.

"Inouye is defintely more of a regulator," one committee aide said yesterday, noting his committee votes against airline deregulation as well as his strong push for legislation to protect the maritime industry, favoring subsidies and broader antitrust exemptions for ocean shippers.

Committee aides also note that Inouye has been a much more strident critic of the Federal Trade Commission than Cannon. Both Cannon and Inouye voted to bar the FTC from implementing its rule that would have required used-car dealers to givel customers more information about the conditions of the cars they sell.

But Inouye went even farther this year, leading the fight to bar the FTC from regulating price-fixing, boycotts or any other anticompetitive or unfair activities conducted by professional groups such as the American Medical Association. Cannon voted against this exemption.

Inouye was also among a group of senators who pressed Congress to enact legislation to bar the FTC from pressing its novel antitrust suit against the four major cereal manufacturers that could have resulted in the breakup of the four companies into smaller firms. That suit was eventually dropped after an FTC law judge ruled that the cereal companies did not violate antitrust laws and should therefore not be broken up.

Cannon's loss came as a surprise to committee aides who said that until late last week they were assured of his victory.

But Republican Chic Hecht, a former state senator, beat the 23-year Senate veteran, by two percentage points. Political analysts attribute Hecht's victory to several factors, including Cannon's age, the pending bribery conspiracy trial in Chicago in which several Teamsters Union officials are accused of trying to bribe Cannon to oppose trucking deregulation legislation, and his reputation as a liberal big spender.

Cannon's reputation as a deregulation proponent came relatively late. He initially opposed deregulation of the airline industry. But when it became clear that the Civil Aeronautics Board would lift most of the government rules on the airline industry single-handedly, Cannon moved in and played a critical role in writing the legislation that eventually passed.

Similarly, Cannon initially was opposed to trucking deregulation. But when the ICC, under President Carter's appointments, began deregulating the industry, Cannon proposed his own bill. Although it was milder than the legislation Carter wanted, the Carter administration came to support the Cannon bill, realizing that it was probably the most it could get.