10 fold margin of safety for pain reduction vs sedation with compound i fig3 but no margin for dexmedetomidine fig4 they further show that compound i is advantageous as an agent for relieving pain and can be taken systemically without the need for intravenous delivery compounds of the invention were evaluated in a flipr assay in order to determine their specificity for five alpha adrenergic receptors the flipr assay measures release of intracellular calcium in response to receptor activation cells are preloaded with a calcium sensitive dye that fluoresces in response to calcium receptors that activate the g protein gq elicit the response alpha adrenergic receptors which normally couple to gi trigger the increase in intracellular calcium when coexpressed with a hybrid gq protein containing a gi receptor recognition domain designated gq i5 conklin et al nature 363 274 6 1993 or with the promiscuous g protein g a16 the assay was performed essentially as follows hek 293 cells stably expressing an alpha 2 receptor and either the chimeric g protein gqi5 or the promiscuous g protein g16 were plated in poly d lysine coated 384 well plates at 20 000 25 000 cells per well and grown overnight in dmem supplemented with 10 fbs cells were washed twice with hbss hepes buffer 1 u00d7 hanks buffered salt solution 20 mm hepes ph 7 4 prior to the addition of fluo 4 am 4 u03bcm fluo 4 am 0 04 pluronic acid in hbss hepes buffer a calcium sensitive dye cells were loaded with dye for 60.