Laurel Race Course will open its gates today to old maidens.

After years of denying nonwinners older than 4 a chance to race, Laurel eased the restriction as of Friday to include 5-year-old maidens. Today, the first such race will take place as two winless 5-year-olds are scheduled to face five winless 4-year-olds at six furlongs.

Originally, 5-year-old maidens were excluded in an effort to improve the quality of racing. In reinstating them, Laurel officials said they will not lessen their product by allowing only those winless 5-year-olds who have not started for a claiming price of $25,000 or lower. Today's race is for "special weights," the highest class of maidens and one that protects horses from being claimed.

Joe De Francis, chief executive officer of Laurel and Pimlico, said the proliferation of racing throughout the region caused the change in policy. "Right now, we are in the most intense battle for horses in our history," he said. "I don't think the change in any way undermines the original intent of the rule."

He said the move was not made to appease any horseman, namely Israel Cohen, the Giant Food president who owns some winless older thoroughbreds.

"We don't change our rules to suit any individual," De Francis said. "He's likely to be a beneficiary of it, but nobody has put forth any strong argument against it. It seems to me to make little sense to prohibit top-quality 5-year-old maidens in Maryland. If a horse has had some problems and missed a year or more of training, they can still turn out to be a top racehorse." Purses Cut

With the handle at Maryland's thoroughbred tracks down about 6 percent, the purses for two stakes races at Pimlico have been cut $25,000 apiece. The Federico Tesio Stakes and the John B. Campbell Handicap will be lowered to $175,000 and $125,000, respectively.

Although Pimlico's meeting will run March 14 through July 3, the Baltimore track disclosed a stakes schedule only through April 28. Richest will be the $200,000 Pimlico Oaks on March 30. Other six-figure races include three handicaps: the Snow Goose on March 23, the Jennings on March 24 and the Gallorette on April 27.

Laurel officials last week blamed the Persian Gulf crisis for much of the decline in business at tracks here and nationwide, and said they hope to see wagers rebound once the novelty of televised war coverage subsides. There are indications that might be happening; Laurel and intertrack partner Pimlico handled $4,423,433 Saturday and Sunday, their best since the Breeders' Cup weekend of Oct. 27-28. . . .

Trainer Ben Perkins Jr. and jockey Rick Wilson connected for three winners yesterday at Laurel: Star Sonnet ($9.40) in the fifth race, Robert's Choice ($11) in the sixth and Bravest Sir ($3.20) in the eighth. . . . Well-favored Sunny Sunrise, a 4-year-old trained by Bud Delp, won the $23,000 allowance feature by a length. He traveled 6 1/2 furlongs in 1:16 4/5 under leading rider Mike Luzzi. . . .

California jockey Russell Baze has mounts in place for each of Laurel's $200,000 races Feb. 16. He's to ride Grade I winner Devil's Orchid, a Californian, in the Barbara Fritchie Handicap and former Marylander Bet the Pot in the General George Stakes. . . .

Larry Collmus of Golden Gate Field and Dave Rodman of Louisiana Downs are the leading candidates to become the full-time announcers at Laurel and Pimlico.