Here , we investigated the low dose pharmacology of orexin receptor antagonist , SB-649868 , on neuroendocrine , sympathetic nervous system , and behavioral responses to insulin-induced hypoglycemic stress , in 24 healthy male subjects ( aged 18-45 years ; BMI 19.0-25 .9 kg/m ( 2 ) ) , using a randomized , double-blind , placebo-controlled , within-subject crossover design .