Prince George's County officials, anxious to bring county development efforts to decaying areas inside the Beltway, have opened a new central neighborhood revitalization office in Bladensburg to help plan growth for old business neigborhoods and to help channel state and federal grants and loans to small businessmen.

The new office, in the historic Indian Queen Tavern on Alt. Route 1, will be headed by Paul Gilbert, who coordinated Baltimore's commercial revitalization program.

Gilbert will direct a "neighborhood business revitalization program," which initially will focus on development of three lagging business communities - Bladensburg, Mount Rainier and Suitland.

The new office will consolidate a number of existing county services and programs under a central administration and will conduct economic surveys and draw up long-term plans for the design and redevelopment of each of the target areas.

The new office, according to County Council Human Resources Director John Griffin, represents an attempt to complement the county's "new quality" programs - designed to attract new business to undeveloped areas in Prince George's - with efforts to stimulate existing, lagging business areas.

In the past, groups like the Neighborhoods United Project and citizens groups in Mount Rainier and other areas have criticized county officials for neglecting older communities.

"I see this as a way of rounding out the county's development efforts," said Griffin. "And I think this is where our emphasis should be in the future.

"The number of choice sites along the big highways are going to diminish. But there are many sites in the old districts that can be redeveloped in the future. This is where we need to turn our attention."

The object of the target programs, Griffin added, is to help small businesses in the old communities "learn marketing techniques, advertising, and the other things that will enable them to compete with the large stores."

The county will invest about $150,000, mostly for salaries, in the revitalization office during this fiscal year. Griffin said. The remainder of this year's budget for the program - which totals almost $900,000 - will come from federal Community Development Block Grants and from other state and federal grant and loan programs.

The budget includes funds for the preparation of studies and plans for the three target areas, for architectural services and completion of previously existing capital improvement and loan programs in Brentwood and Langley Park.

The planning and design studies for Mount Rainier, Suitland and Bladensburg - necessary for any Community Development Block Grant - will not be completed until late next year. It will be March 1980 before most businessmen in the three communities begin receiving loans or before capital improvements such as sidewalks or parking lots are built.

According to county projections, the actual implementation of revitalization plans in the affected areas will extend over at least three years after construction begins.

Linda Nalls, Mount Rainier mayor, said the new program should help restore the confidence of businessmen in older communities.

"It's a response, and I'm grateful for anything the county will do for us," Nalls said. "It's been so long since anything was done - I need all the help I can get."

Nalls estimated that it would be three to four years before the effects of the program are visible in the target communities.