Table 2. Calcium-Mobilization Activities for the P2Y2R Antagonists 6–19.
| example | R3 | hP2Y2 pKba |
|---|---|---|
| 7 | NH2 | 6.56 ± 0.14 (4) |
| 8 | PhNH | IAb (3) |
| 9 | PhCH2NH | IA (3) |
| 10 | PhCH2CH2NH | IA (3) |
| 11 | 1-methyl piperazin-4-yl | IA (3) |
| 12 | morpholinyl | IA (3) |
| 13 | piperidinyl | IA (3) |
| 14 | 2-methoxyethan-1-aminyl | 6.60 ± 0.21 (4) |
| 15 | 2-methoxypropan-1-aminyl | 6.56 ± 0.09 (3) |
| 16 | 2-ethoxyethan-1-aminyl | 6.73 ± 0.05 (3) |
| 17 | 2-isopropoxyethan-1-aminyl | 6.49 ± 0.09 (3) |
| 18 | 2-phenoxyethan-1-aminyl | IA (3) |
| 19 | phenyl | IA (3) |
a
The estimated affinity value for each antagonist (pKb) was calculated using the Gaddum equation from the shift of the UTPγS concentration–response curve brought about by the addition of a single concentration of the antagonist. The data shown are the means ± SEM, and the numbers of separate experiments are given in parentheses.
b
IA = inactive; i.e., less than a 50% inhibition of the response to 0.1 μM UTPγS in the presence of a 10 μM concentration of the compound (n = 3).