Table 2.
Pharmacological Parameters of Divalent Metal Ion under Different pH Conditions at GPR68a
| efficacy and potency | Hill slope | |||||
|---|---|---|---|---|---|---|
| stimulation | inhibition | stimulation | inhibition | |||
| metal ions | pH | Emax at (μM) | pEC50 (nM) | pEC50 | Hill 1 | Hill 2 |
| Ca2+ | 7.40 | 1.9 ± 0.3 (1000) | 3.88 ± 0.23 | NA | 1.06 ± 0.49 | NA |
| 7.00 | 1.9 ± 0.3 (1000) | 3.78 ± 0.13 | 1.31 ± 0.42 | |||
| 6.80 | 2.1 ± 0.2 (1000) | 3.78 ± 0.11 | 1.19 ± 0.28 | |||
| 6.40 | 1.6 ± 0.1 (1000) | 3.81 ± 0.12 | 1.52 ± 0.55 | |||
| Cd2+ | 7.40 | 36.0 ± 6.8 (1) | 7.28 ± 0.05 (53) | 4.22 ± 0.20 | 1.41 ± 0.19 | 0.55 ± 0.19 |
| 7.00 | 5.1 ± 0.4 (1) | 7.69 ± 0.06 (20) | 4.21 ± 0.10 | 1.04 ± 0.11 | 0.80 ± 0.15 | |
| 6.80 | 3.0 ± 0.3 (1) | 7.75 ± 0.04 (18) | 3.81 ± 0.25 | 1.02 ± 0.10 | 0.58 ± 0.08 | |
| 6.40 | 1.3 ± 0.1 (1) | 7.62 ± 0.25 (24) | 3.31 ± 1.39 | 1.04 ± 0.50 | 0.47 ± 0.35 | |
| Co2+ | 7.40 | 33.5 ± 8.9 (30) | 7.14 ± 0.05 (72) | NA | 1.34 ±0.19 | NA |
| 7.00 | 4.4 ± 0.7 (30) | 7.45 ± 0.07 (35) | 0.99 ± 0.13 | |||
| 6.80 | 2.8 ± 0.4 (30) | 7.34 ± 0.08 (46) | 0.95 ± 0.14 | |||
| 6.40 | 1.4 ± 0.1 (30) | 6.39 ± 0.54 (407) | 0.34 ± 0.18 | |||
| Cu2+ | 7.40 | 2.7 ± 1.0 (1) | NA | NA | NA | NA |
| 7.00 | 1.6 ± 0.1 (1) | 6.09 ± 0.30 | 5.61 ± 0.17 | 1.18 ± 0.42 | 1.57 ± 0.44 | |
| 6.80 | 1.5 ± 0.1 (1) | 6.47 ± 0.18 | 5.43 ± 0.05 | 0.60 ± 0.15 | 2.22 ± 0.54 | |
| 6.40 | 1.0 ± 0.0 (1) | NA | 5.31 ± 0.03 | NA | 2.27 ± 0.26 | |
| Fe2+ | 7.40 | 10.2 ± 2.0 (30) | 4.13 ± 0.09 | NA | 0.64 ± 0.06 | NA |
| 7.00 | 3.7 ± 1.1 (30) | 5.91 ± 0.05 | 1.71 ± 0.29 | |||
| 6.80 | 3.0 ± 0.3 (30) | 6.26 ± 0.05 | 1.07 ± 0.11 | |||
| 6.40 | 1.3 ± 0.1 (30) | 5.33 ± 0.20 | 0.81 ± 0.27 | |||
| Mn2+ | 7.40 | 24.3 ± 5.3 (30) | 5.40 ± 0.05 | NA | 0.59 ± 0.04 | NA |
| 7.00 | 4.7 ± 0.2 (30) | 5.76 ± 0.07 | 0.52 ± 0.04 | |||
| 6.80 | 2.7 ± 0.2 (30) | 4.79 ± 0.27 | 0.32 ± 0.04 | |||
| 6.40 | 1.3 ± 0.1 (30) | 2.91 ± 1.07 | 0.42 ± 0.11 | |||
| Ni2+ | 7.40 | 20.2 ± 5.9 (30) | 6.91 ± 0.09 (123) | NA | 1.04 ± 0.19 | NA |
| 7.00 | 4.2 ± 0.7 (30) | 7.12 ± 0.09 (76) | 1.09 ± 0.22 | |||
| 6.80 | 2.9 ± 0.2 (30) | 7.00 ± 0.08 (100) | 0.95 ± 0.15 | |||
| 6.40 | 1.3 ± 0.1 (30) | 3.52 ± 1.61 | 0.27 ± 0.07 | |||
| Zn2+ | 7.40 | 9.1 ± 2.1 (1) | 6.68 ± 0.03 (209) | 5.33 ± 0.05 | 2.07 ± 0.20 | 1.55 ± 0.15 |
| 7.00 | 3.2 ±0.5 (1) | 6.88 ± 0.06 (132) | 4.86 ± 0.05 | 1.60 ± 0.25 | 1.17 ±0.15 | |
| 6.80 | 2.3 ± 0.2 (1) | 7.01 ± 0.08 (98) | 4.59 ± 0.05 | 1.09 ± 0.17 | 1.16 ±0.14 | |
| 6.40 | 1.3 ± 0.1 (1) | 6.92 ± 0.10 (120) | 3.89 ± 0.09 | 0.93 ± 0.19 | 0.84 ± 0.09 | |
a
Concentration-response curves are presented in Figure 3 and Figure S1. Emax (fold of basal) for the stimulation activity represented mean ± SEM from a minimum of 3 independent assays, each in triplicate or quadruplicate. The Emax for Ca2+ is determined at 1 mM, Cd2+, Cu2+, and Zn2+ at 1 μM, Co2+, Fe2+, Mn2+, and Ni2+ at 30 μM. Under each pH condition, buffer alone served as basal for normalization (with basal = 1.00). Potency and Hill slope values were retrieved from fittings with pooled and normalized results using the Prism 8.4 built-in four-parameter logistic function or bell-shaped concentration-response function.