The professors were demonstrating at Pokhara, about 200km west of Kathmandu, violating a day curfew imposed to prevent demonstrations, police said on the telephone on Wednesday.
Krishna Adhikari, a professor who was among those arrested, said the academics had conducted a peaceful rally when police stopped them, loaded them up in police trucks and drove them to detention centres.
"We condemn the police breaking our peaceful rally," Adhikari said speaking on his cellular phone.
Police did not open fire on the professors even though security forces were given orders to shoot violators of the 8am-7pm curfew.
The order to stay off the streets was imposed a day after thousands of pro-democracy protesters clashed with police in Pokhara, injuring at least a dozen people.
Meanwhile, Indian envoys carried a crisis message to Nepal's king in the run-up to a major pro-democracy protest marking the start of the third week of a bitter general strike.
Shyam Saran, India's foreign secretary, and special envoy Karan Singh were first expected to see the king on Wednesday, but Indian officials later said the meeting would now be held on Thursday.
Police fire tear gas at
demonstrators in Pokhara
Singh said on Tuesday that civil unrest against the monarchy was "spinning out of control" in the Himalayan nation.
"The prime minister has asked me me to go to Nepal to take a message to the king and also make a general assessment of the situation," said Singh, whose wife is the grand-daughter of the last Rana dynasty prime minister of Nepal.
"I also expect to meet leaders of the political parties while I am there," said the 75-year-old, who said India was worried the civil unrest could lead to a humanitarian crisis in the landlocked nation.
Nepal's royal government has imposed a daylong curfew and given security forces orders to shoot violators on sight in a western town where thousands of pro-democracy protesters clashed with police a day earlier.
An announcement on state-run Radio Nepal on Wednesday said the curfew would be imposed in Pokhara, about 200km west of Kathmandu.
The order to stay off the streets was imposed after police on Tuesday fired rubber bullets and tear gas at thousands of protesters calling for King Gyanendra's removal in defiance of a government ban on demonstrations in Pokhara.
Civil unrest in Nepal could lead to
a humanitarian catastrohope
At least a dozen people were injured, according to doctors at the Gandaki Hospital.
Meanwhile, a woman who was hit in the face by a tear-gas shell has become the sixth person to die in two weeks of protests.
Officials said on Wednesday the woman, who was injured on Tuesday during a protest in the town of Nepalgunj, 500km west of Kathmandu, died while being taken to a hospital in the Indian city of Lucknow.