Barry L. Switzer, head football coach at the No. 4-ranked University of Oklahoma and one of the most successful collegiate coaches in the country, was one of three individuals named in an Internal Revenue Service subpoena served for records of a Las Vegas casino, it has been learned.

Two of the individuals, Clifford W. (Cliff) Culpepper, an Oklahoma City oil man, OU football booster and frequent visitor to Las Vegas, and Clarence R. Wright, an Oklahoma City area banker and developer, confirmed they had been notified of the subpoena.

It was also confirmed independently in Las Vegas that the subpoena was served on the Sands Hotel and casino for what Culpepper described as records of hotel bills, lines of credit and gambling activities by all three individuals during the year 1976.

Switzer, reached at his Norman, Okla. home, refused to comment.

The IRS would not comment on the subpoena and it could not be learned what prompted it or why Switzer was included. Culpepper said he is audited annually by the IRS, but he said both he and casino officials are puzzled by the subpoena. Switzer and Culpepper have been in oil investments together, is have Wright and Culpepper.

Culpepper said while there are records of three visits by him to the Sands during 1976 there are none reflecting visits by Switzer or Wright.

Switzer is known to have made trips to Las Vegas and gambled a few hundred dollars on a $3,000 line of credit, but at the Las Vegas Hilton hotel and casino, not the Sands. That sort of gambling is not connected with sports gambling and there never has been any indication Switzer has been involved in gambling on sports. The Sands does not have a sports-book-making outlet.

Bill Murray, executive director of the American Football Coaches Association in Durham, N.C., said that because Switzer was included in a subpoena served on a gambling casino he probably would be asked, for his own benefit, to appear before the association's ethics committee.

Switzer has been head coach at Oklahoma for six years and has compiled a record of 60 wins, six losses and two ties. He has won the Big Eight conference championship, or a share of it, each year he has been head coach and has won two national championships.