Species variation in H1-receptor antagonist potency (Ki, nM)
| Antagonist | Guinea pig | Human | Rat | Bovine | ||||
|---|---|---|---|---|---|---|---|---|
| h14-a (CHO) | H14-b(brain) | h1 (CHO) | H1(brain) | h1 (C6) | H1(brain) | h1 (COS-7) | H1 (Adrenal Medulla) | |
| Mepyramine | 0.7 | 0.8 | 1.1, 4.0 | 1.0 | 1.7 (1.0)4-c | 9.1 | 2.6 | 0.9 |
| (+)-Chlorpheniramine | 0.9 | 0.8 | 3.5, 2.5 | 4.2 | 7.5 (4.4)4-c | 9.1 | 8.0 | 4.4 |
| (−)-Chlorpheniramine | 103 | 200 | 316 | 350 | 540 (>620)4-c | 500 | 760 | 350 |
| Triprolidine | 0.7 | 0.2 | 1.0 | 3.7 | 2.0 | 5.6 | n.d. | 0.8 |
Unless otherwise stated, values show Kideterminations from inhibition of [3H]mepyramine binding. n.d., not determined.
↵4-a h1 = transfected H1-receptor cDNA.
↵4-b H1 = native/endogenous H1-receptor.
↵4-c Values in parentheses show the values obtained from functional studies of the endogenous H1-receptor present in rat C6 cells (Peakman & Hill, 1994).