Table 2.

Histamine dose–response parameters

Receptor type	EC50 (μm HA)	nH	n (cells)
HCLA homomers	25.0 ± 8.8	2.6 ± 0.6	9
HCLB homomers	14.1 ± 1.7	2.0 ± 0.4	6
HCLA/HCLBa	4.8 ± 2.6	1.0 ± 0.2	9
HCLA/HCLBb	1.2	1.5	9
Nativec	24.0 ± 8.5	2.5 ± 0.5	27

All fitted parameters are mean ± 1 SD.

^aSimple Hill equation fitting parameters (see Eq. 1, Fig. 2A).

^bHeteromeric component parameters of the composite Hill equation (see Materials and Methods, Eq. 2, and Fig. 2B).

^cData from Skingsley et al. (1995).