BETHESDA, MD. — A joint venture between MRP Realty and Rockpoint Group has secured a $150 million acquisition loan for the Air Rights Center, a 688,717-square-foot office development in Bethesda. The development includes three buildings in the north, east and west towers. The property is 93 percent leased to a diverse tenant base. John Campanella and Paul Spellman of Cassidy Turley represented the joint venture in securing the loan, which was provided by a commercial bank.