Hundreds of demonstrators blocked two bridges and two tunnels in Manhattan during the height of the rush hour yesterday, causing serious gridlock for over an hour in a coordinated protest of proposed state and city budget cuts and of police brutality.

The demonstrators, who included students and professors from the City University of New York, the homeless, health care workers, AIDS activists, the disabled and families of people killed by the police, blocked the entrances to the Queens-Midtown Tunnel, the Brooklyn-Battery Tunnel, the Brooklyn Bridge and the Manhattan Bridge between 5:30 and 6 P.M., enraging motorists on their way home from work.

At the Brooklyn-Battery Tunnel, some motorists hopped out of their cars and yelled, "More cutbacks! Let them work!"

The action, which was hatched shortly after the election of Gov. George E. Pataki last November, suggested a growing frustration over spending reductions and was intended as the beginning of a round of protests by a united front of myriad constituencies. The police said that roughly 185 people were arrested on disorderly conduct charges.

The demonstrators, many gleeful but determined in the balmy spring weather, shouted their opposition to the yet-to-be-enacted budget of Mr. Pataki and the expected budget of Mayor Rudolph W. Giuliani. Many expressed heartfelt anger at cuts that would affect them personally.

"They want to take our crumbs away," said Joseph Maldonado, a student at CUNY. "That's all we got, but we like our crumbs."

The most serious rush hour disruption occurred at the Midtown Tunnel, where some 75 demonstrators shut down all six lanes feeding into the tunnel entrance on 36th Street for around a half-hour and backed up cars to 42d Street. The police diverted motorists onto Second Avenue to try to ease the gridlock. The protesters carried a banner that read, "Rudy: It's Our Quality of Life. New York Demands Public Health."

At the Battery Tunnel in lower Manhattan, about 50 demonstrators, mostly CUNY students, jumped the barricade to the entrance ramp and unfurled a banner that said, "Stop for Peaceful Protest." Motorists had no choice but to do just that as the protesters slowly backed their way into the mouth of the tunnel, where they sat down three deep.

Honking and shouting motorists were stretched for blocks. Philip Lerner, a lawyer on his way home with his wife, Roslyn, said he had graduated from CUNY himself and was sympathetic to the cause -- but not to this particular protest. "This is stupid," he said. "I told my wife to run them over."

The protesters themselves were aware, apparently, that their action would not win them immediate sympathy from the homebound commuters. The point, they said, was to shut down the city briefly to suggest that depriving students of their education would shut down the city in a far more serious, permanent way.

"The first thing I would say to them is 'I'm sorry,' " said Mr. Maldonado, 22, before leaving Battery Park for the tunnel. "I know what it's like to have a hard day at work. I empathize. But we're out to give people a headache like the headaches we'll have, trying to figure out how to pay for school next year."

It took about 10 minutes before the police arrived and began arresting the demonstrators. Traffic started flowing after about 20 minutes.

Traffic over the Brooklyn Bridge was halted for about 20 minutes, when a group of about two dozen homeless people and advocates for the homeless unfurled a banner declaring, "The City Is Ours," and sat down across the entrance ramp.

"If enough voices come together, then there is a sound," said Curtis Roberts, a homeless man who participated in the action. "If there is a sound, then maybe there will have to be a response."

At the Manhattan Bridge, two dozen demonstrators wearing signs on their stomachs calling for an end to police brutality locked arms and stood across the Manhattan entrance to the bridge. Within 15 minutes, police had arrested them and opened up the bridge.

The most arrests took place at the Midtown Tunnel, where 75 people were taken into custody. The police commandeered a city bus, emptying it of passengers, to take away the protesters.

All in all, there was little resistance given to the police. However, spokesmen for the protest said that some demonstrators said they were dragged and dropped on the street as they were arrested.

Many motorists expressed scant sympathy for the demonstrators. Michael Waldman was on his way home to West Hempstead, L.I., with his mother, Linda, when he came upon the barricaded Midtown Tunnel. "This is the wrong way to go about it," he said. His mother added, "We would have been sympathetic to them. But this is no way to get attention."

Some of the police were openly critical of the demonstrations. "Police resources are stretched very thin right now because of Unabom and the Oklahoma bombing," said Police Chief Louis Anemone. "I thought this was a very selfish act. To have diverted police for a childish demonstration like this is criminal."

The demonstrators at the Midtown Tunnel did allow one car through, because a woman in it was going into labor.

Some 30 groups were involved in the protest, including ACT UP, the Committee Against Anti-Asian Violence, the National Congress for Puerto Rican Rights and the CUNY Coalition Against Cuts.

The protest began with four overlapping rallies that got underway in late afternoon, each focusing on different issues. Jobs, housing and public assistance were the target of a rally at Cadman Plaza in downtown Brooklyn. At Bellevue Hospital, the emphasis was on health services and AIDS services. At 1 Police Plaza, it was police brutality, and at John Jay College for Criminal Justice on 59th Street and 10th Avenue, CUNY and public education were the subject.

Around 5:30 P.M., demonstrators peeled off from these rallies and converged on the tunnels and bridges. The actual targets were known only to the leaders of the demonstration until the last minute to create maximum impact.

Photos: Demonstrators blocked the Brooklyn Battery Tunnel at the evening rush-hour yesterday as part of a coordinated citywide protest of proposed state and city budget cuts and of police brutality. (Michelle V. Agins/The New York Times); In lower Manhattan at the foot of the Manhattan Bridge, protesters from the Committee Against Anti-Asian Violence and from the National Congress for Puerto Rican Rights blocked the entrance before being arrested. (Philip Greenberg for The New York Times); A protester being carried by police officers yesterday after 75 people blocked lanes feeding into the Queens-Midtown Tunnel on 36th Street. (Paul G. Burnett/The New York Times)