Table 2.

Effect of Mg²⁺ on the potency and maximal activation of L-Orn at mGPRC6A

	EC50 (μM)	pEC50±s.e.m.	Max±s.e.m.a (%)	n
L-Orn/0 mM Mg2+	63.2	4.21±0.07	103±5	3
L-Orn/1 mM Mg2+	63.6	4.20±0.001	100	3
L-Orn/5 mM Mg2+	61.2	4.23±0.10	122±6	3
L-Orn/20 mM Mg2+	39.5	4.41±0.05	184±18	3
L-Orn/40 mM Mg2+	34.5	4.46±0.03*	192±19	3

The IP turnover assay was used to determine the EC₅₀ value of L-Orn in the presence of various concentrations of Mg²⁺. Significant difference from L-Orn/1 mM Mg²⁺ (pEC₅₀ value) was determined:

^*P<0.05 (ANOVA followed by Dunnett's test).

All experiments were performed in the presence of 1 mM Ca²⁺.

^aThe maximal responses are normalized to the maximal response to L-Orn at 1 mM Mg²⁺.