Richard Stone, the special U.S. envoy to Central America, conferred with Nicaraguan leaders today in an atmosphere of increasingly acrimonious confrontation between the Reagan administration and this country's revolutionary government.

Stone, who arrived in a U.S. Air Force executive jet, said his day of talks here was of "profound importance" for what he described as a search for peace that has taken him to 10 countries in his inaugural two-week tour.

The envoy, a former senator from Florida, met successively with Foreign Minister Miguel D'Escoto, officials of the Defense and Interior ministries and chief of state Daniel Ortega, head of the government's three-man junta.

Although Stone was granted access to the highest levels of the leadership, there were no indications of a basic change in U.S.- Nicaraguan relations. Tension is at its highest point since the Sandinista revolutionaries took power in July 1979.

The strain reflects what the U.S. and Nicaraguan governments have described as a vital struggle over the future of Central America, with the Reagan administration pledged to frustrate Cuban and Soviet influence in the region and the Sandinistas looking forward to a change in what they view as a history of U.S. imperialism on the isthmus.

More immediately, Nicaragua only Monday expelled three U.S. diplomats, charging they were CIA agents and asserting that one supervised a U.S. plot to poison D'Escoto with thalium in a bottle of Benedictine liqueur. The next day, the United States shut all six Nicaraguan consulates outside Washington and expelled 21 diplomats who staffed them.

In addition, Reagan administration officials have acknowledged that they are providing funds, training and other aid for Nicaraguan irregulars fighting to overthrow the Sandinistas. The clashes are causing almost daily casualties, some civilian, and in Nicaraguan eyes have cast the United States in the role of an attacker.

Both government-controlled morning newspapers published front-page pictures of Nicaraguan women mourning the loss of a 21-year-old reservist, who the papers said was killed last Saturday by counterrevolutionary guerrillas supported by the United States and Honduras. Near the photos were announcements of Stone's visit.

Stone turned down an invitation to visit the border areas where guerrillas mount regular attacks. The units were the subject of Stone's briefings with Army Chief of Staff Joaquim Quadra and an aide to Lenin Cerna, the head of State Security who announced the alleged poisoning plot against D'Escoto.

Stone is viewed with suspicion here because of his association with the former rightist government of Romeo Lucas Garcia in Guatemala, for which he lobbied in Washington after a 1980 Democratic primary defeat in his bid for reelection. D'Escoto on Tuesday said he thought Stone is inappropriate as special ambassador because he "lacks moral values" and has been involved with "assassin governments."

Ortega and Stone were involved in a bitter argument in a U.S. Capitol corridor soon after Sandinista forces threw out the U.S.-backed dictatorship of Anastasio Somoza in 1979. Following that confrontation, Ortega denounced Stone at the United Nations, and the memory of their clash has remained very much alive here.

Against that background, Stone's meetings with top government officials were seen as positive even if they accomplished nothing. But in an indication that the leadership here may expect precisely that result, the official Sandinista Front newspaper recalled today that Thomas Enders, outgoing assistant secretary of state for inter-American affairs, visited here two years ago for talks that "produced no positive result at all."

"Although his credentials are not the best to guarantee success of a dialogue with the revolutionary government, Stone has been invited in the framework of our policy of making all necessary efforts to initiate a constructive dialogue with the Reagan adminstration," said the paper, Barricada.

One signal of how the Sandinista leadership views the future came minutes after Stone's arrival at Augusto C. Sandino International Airport. A pair of T33 jet trainers, an even older T28 and several other aircraft flew sweeps over the terrain. Two paratroopers jumped from a Soviet-made byplane and floated slowly to earth.