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Table 2 pKD values for H3 antagonism

From: Antagonist affinity measurements at the Gi-coupled human histamine H3 receptor expressed in CHO cells

Agonist pKD values            
  Iodophen-propit n Cloben-propit n zolatidine n conessine n thioperamide n cimetidine n
histamine 8.65 ± 0.07 19 9.42 ± 0.04 9 6.51 ± 0.07 19 8.29 ± 0.05 15 7.22 ± 0.04 23 5.64 ± 0.11 11
N-α-methylhistamine 8.59 ± 0.10 16 9.42 ± 0.06 15 6.46 ± 0.07 17 8.27 ± 0.04 12 7.37 ± 0.06 18 5.57 ± 0.08 9
R-α-methylhistamine 8.57 ± 0.09 15 9.21 ± 0.08 15 6.52 ± 0.06 14 8.24 ± 0.06 9 7.33 ± 0.04 17 5.62 ± 0.12 8
S-α-methylhistamine 8.72 ± 0.05 14 9.25 ± 0.05 13 6.54 ± 0.07 18 8.28 ± 0.05 12 7.20 ± 0.05 17 5.64 ± 0.06 9
imetit 8.78 ± 0.06 16 9.20 ± 0.05 12 6.62 ± 0.08 17 8.24 ± 0.10 12 7.29 ± 0.06 13 5.64 ± 0.08 10
immepip 8.66 ± 0.07 14 9.36 ± 0.04 12 6.55 ± 0.07 17 8.09 ± 0.07 12 7.22 ± 0.09 15 5.70 ± 0.09 9
immethridine 8.81 ± 0.08 12 9.21 ± 0.06 12 6.66 ± 0.05 12 8.42 ± 0.10 11 7.31 ± 0.06 12 5.72 ± 0.09 4
proxyfan 8.82 ± 0.05 7 9.25 ± 0.08 7 6.78 ± 0.06 9 8.56 ± 0.08 5 7.59 ± 0.03 9 5.61 ± 0.11 6
VUF 8430 8.53 ± 0.08 6 9.11 ± 0.19 4 6.38 ± 0.10 4 8.15 ± 0.08 4 7.15 ± 0.27 4 5.53 ± 0.13 4
impentamine 8.60 ± 0.09 6 9.01 ± 0.10 4 6.52 ± 0.10 4 8.38 ± 0.11 4 7.47 ± 0.10 5 5.70 ± 0.01 5
agonist Log KD values            
  Dimethin-dine n Chlorpheni-ramine n VUF 5681 n ranitidine n triprolidine n clemastine n
histamine 5.63 ± 0.07 7 5.32 ± 0.06 8 7.77 ± 0.08 5 5.05 ± 0.08 9 5.35 ± 0.05 7 5.73 ± 0.08 10
N-α-methylhistamine 5.67 ± 0.17 6 5.51 ± 0.07 3 7.95 ± 0.14 4 5.05 ± 0.08 9 5.34 ± 0.08 6 5.69 ± 0.13 7
R-α-methylhistamine 5.65 ± 0.04 5 5.44 ± 0.04 4 7.60 ± 0.07 4 5.18 ± 0.06 7 5.58 ± 0.05 5 5.79 ± 0.09 7
S-α-methylhistamine 5.67 ± 0.03 4 5.44 ± 0.08 3 7.75 ± 0.04 4 4.95 ± 0.10 7 5.47 ± 0.08 6 5.74 ± 0.11 8
imetit 5.60 ± 0.16 8 5.58 ± 0.08 4 7.85 ± 0.08 4 4.96 ± 0.09 7 5.43 ± 0.09 7 5.69 ± 0.15 6
immepip 5.72 ± 0.16 5 5.59 ± 0.12 4 7.72 ± 0.10 3 5.12 ± 0.06 6 5.61 ± 0.13 4 5.79 ± 0.15 6
immethridine 5.38 ± 0.05 9 5.53 ± 0.05 4 7.79 ± 0.12 4 5.19 ± 0.09 3 5.53 ± 0.13 3 5.50 ± 0.10 3
proxyfan 5.24 ± 0.14 3 5.39 ± 0.11 5 7.80 ± 0.03 3 4.97 ± 0.12 5 5.23 ± 0.07 5 5.60 ± 0.11 6
VUF 8430 5.11 ± 0.09 3 5.13 ± 0.15 4 7.71 ± 0.16 3 4.72 ± 0.01 3 5.26 ± 0.10 3 5.26 ± 0.06 4
impentamine 5.59 ± 0.24 3 5.21 ± 0.22 4 *   5.10 ± 0.09 5 5.65 ± 0.15 4 5.73 ± 0.09 5
  1. pKD values for 12 antagonists as determined from measurements of CRE-SPAP production from CHO-H3-cells made in the presence of the 12 different agonists. Values represent mean ± s.e.mean of n separate experiments. The pKD values quoted are for antagonism of the first component of the impentamine response.
  2. * it was not possible to determine a pKD value for VUF 5681 in the presence of impentamine due to the partial agonist nature of both responses.