The Italian Parliament decided tonight to disregard appeals by top Christian Democratic leaders and voted to send two former defense ministers accused of involvement in Italy's Lockheed scandal to trial before the Constitutional Court.

The vote came after an often-emotional, sever-day debate and marked the first time in recent Italian history that the parliamentary immunity of Cabiney ministers was lifted to allow them to be put on trial. in a joint session, Italy's 952 deputies and senators voted in favor of trials for former Christian Democratic Defense Minister Luigi Gio and his Social Democratic successor, Mario Tanassi.

Gui headed the Defense Ministry from 1968 to 1970 and Tanassi from 1970 to 1972.

Documents published last year by the U.S. Senate Subcommittee on Multinational Corporations indicated that during that period Lockhed paid bribes of $2 million to italian officials to promote the sale of 14 C-130 transport planes.

The votes were 487 to 451 against Gui and 513 to 425 against Tanassi. The votes were widely considered a major defeat for Italy's ruling party, the Christian Democrats.

It takes in approval of 477 Parliament members to lift immunity.

Former Premier Aldo Moro, the president of the Christian Democratic party accused italy's communists and Socialists of turning the session into a "political" trial of his party's 30 years of rule.

Tonight's vote was seen as a victory for the Communists, who support the present minority Christian Democratic government, in Parliament but still formally consider themselves part of the opposition. Sources said the vote was not likely to alter the status of the present government but could help the Communists, whose rank the file members have been suspicious of the party's cooperation with their traditional enemy, the Christian Democrats.

The decision to put the two ministers on trial also appeared likely to restore some credibility to Italy's taraished political institutions.

Many Italians are convinced that top politicians here can get away with anything, and only last month were embittcred by the investigating commission's decision in January to drop charges against another suspect in the Lockheed scandal, former Christian Democratic Premier Mariano Rumor.

"For the first time in a year I can really say I'm proud of my country," a page at the Chamber of Deputies said tonight. "I thought they'd be freed by the traditional buddy system, but for once that didn't work."