This is a single centre, 2 part study in older subjects. Part 1 (Pharmacokinetic [PK] Assessment) is a double blind, randomized, placebo-controlled 4-period crossover study investigating the PK profile of four different doses of GSK2981710. Eight subjects will receive a single dose of GSK2981710 10 gram (g), 20 g, 30 g, 40 g or placebo in the morning and have PK assessments (every 0.5 hrs up to 8 hrs post-dose) throughout the day in each period. Each subject will complete a total of four dosing sessions and 4 days of PK assessments in 2 weeks. The Part 1 PK data will be used for dose selection and pharmacodynamic (PD) assessment period in Part 2. If the data from Part 1 is inconclusive, an additional 8 subjects may be recruited and Part 1 repeated (possibly dropping some doses) to increase confidence. A subject's total participation in Part 1 of the study will last a maximum of approximately 7 weeks including screening. Subjects who have completed Part 1 may be screened for eligibility and enrolled for Part 2.