Secretary of State Cyrus R. Vance sounded the opening notes yesterday in the administration's campaign to wring approval from a deeply divided Senate for the Panama Canal treaties.

He was promptly put on notice that the quest for the needed 67 votes - two-thirds of the Senate - will be a grueling political struggle.

The three weeks of hearings by the Senate Foreign Relations Committee, which opened yesterday, are being billed as a "forum for educating the Senate and the American public" onthe pros and cons of the treaties turnning over eventual control of the canal to Panama.

In particular, Vance was warned that several uncommitted senators are deeply disturbed by recent statements of a Panamanian negotiator indecating apparent confliets in official U.S. and Panamanian interpretations of how the pacts affect vital U.S. interests in the canal.

The senators expressed particular coreern about whether Panama disputes the administration's contention that the United States retains the right to intervene in the canal and the right to priority passage of U.S. vessels through the canal in time of war.

Among those voicing this concern was Sen. Howard H. Baker Jr. (R-Term), the Senate minority leader and a man whose support is regarded as critically important in the impending fight to get the treaties through the Senate.

Baker, who said he is still undecided about his vote, warned Vance that, unless the question of where the Panamanian government stands on these points is clarified satisfactorily, "the chances that the Senate will advise and consent to these treaties will be greatly dimisnished."

That exchange came as Vance, flanked by the two U.S. treaty negotiators, Ellsworth Bunker and Sol M. Linowitz, strove to reassure the committee that the treties adequately protect U.S. security and economic interests while demonstrating to the world that the United States is not an imperialistic exploiter."

In essence, Vance's message was that the treaties establish a long-term basis for open and effective operation of the canal, safeguard the U.S. strategic interest in the canal, remove the chief cause of tension in U.S. relationswith Latin America and accomplish those ends without placing any new burdens on the U.S. taxpayer.

"Panama is a small country," he said. "It would be all too easy for us to lash out in impatience and frustration, to tell Panama and Latin America - and other countries around the world - that we intended to wpeak loudly and carry a big stick and to turn away from the treaties four Presidents have sought over so long a time."

But, he added. "I believe the American people want to live in peace with their neighbors . . . want to be strong, but to use their strength with restraint . . . want all peoples every where, to have their own chance to better themselves and to live in sell-respect.

"And," Vance concluded "that is why I am convinced that ofter the national debate they deserve, these treateries will be approved without reservations by the Senate, with the strong support of the American people."

While Vance was appeating before the Senate committee two other administration spokesmen. Defense Secretary Harold Brown and Gen.George Brown, chairman of the Joint Chiefs of Staff, were carrying out another prong of the oftensive on the other side of the Capitol.

Testifying before the House International Relations Committee, thet stressed the Defense Department's view that use of the canal is more important to the United States than ownership and that while ability to defend the canal is essential that ability can be better achieved through cooperation with a friendly Panama than by maintaining a garrison in the midst of hostile surroungings.

The reception accorded the administration's arguments by both caommittees was cordial and sympathetic. But as several members the Senate committee told Vance U.S. public opinion currently seems opposed to the treaties. A mossive effort of persuasion and education, they said is required if that opinion - and the Senate - is to be swung around to the administration's point of view.

Baker and Sen.Richard B. Stone Flan cited statements made in the August by Romulo Escobar Betanemurt, one of the Panamanian negotiators of the accords.

Both senators said that Escobar's public statements appeared to contradict the assurances given the committee by Vance and indicated a serous conflicted of interpretation" between Washington and Panama

Stone added that there appear to be four key points where Escobar's remarks conflicted with Washington public statements about the meaning of the treaties. He listed them as:

Whether Panama recognizes the U.S.right to intervene in the canal of it decides that thae neutrality provisions have been violated.

Whether the provisions for "expeditious transit" of U.S.ships in wartime mean that U.S.vessels waiting to move through the canal "go tothe bead of the line" of have to wait their turn.

Whether the treaties give the United States exclusive rights to build a new sea level canal through Panama if both countries agree it is needed.

In response, linowitz told the committee that the Carter administration sticks to its interpretation of these points and considers them binding on Panama. He added that Washington had expressed concern about Escobar's statements to the Panamanian government and had been assured that "they would not be repeated."

In regard to the key question of the U.S.right to intervene. Linowitz and Vance cited the remark made by Panama's military ruler. Gen.Omar Torrijos at the Sept.7 treaty signing eermonies. At the time Torrijos said the treaties could have the effect of placing Panama permanently "under the nuclear umbrella of the Pentagon."

Under prodding rom Baker though Linowitz acknowledged that the Panamanian government had not publicly repudiated Escobars statements or said openly that it a less with Washington's interpretation of the disputed points.

After Baker and Stone noted that failure to clear up these questions of interpretation could uneopardize the treaties chances for passage.Linowitz agreed to seek some kind of clarification from the Panamanian government. However, he and the senators left unanswered the question of what kind of response would prove satisfactory to the committee.