Gi- and Gq-coupled ADP (P2Y) receptors act in opposition to modulate nociceptive signaling and inflammatory pain behavior

Table 1 P2Y receptors and nucleotide agonists.

Receptor	Signaling	Preferred Agonist	ΔC_T (DRG)
P2Y1*	Gq/11	ADP	6.22 ± 0.11
P2Y2*	Gq/11	ATP = UTP	6.17 ± 0.08
P2Y4*^‡	Gq/11	ATP = UTP	13.63 ± 0.31
P2Y6*	Gq/11	UDP	10.92 ± 0.14
P2Y12	Gi/o	ADP	7.55 ± 0.26
P2Y13**	Gi/o	ADP = IDP	9.78 ± 0.59
P2Y14	Gi/o	Glycosylated UDP	7.91 ± 0.59

Relative expression levels of mRNA for P2Y family members in DRG are expressed as the normalized cycle threshold (ΔC_T): the P2Y C_T value minus the C_T for the reference standard, GAPDH. *Previously published data [28]. ^‡Rodent P2Y4 receptor shows equivalent responsiveness to ATP and UTP; the human receptor is selective for UTP. **Mouse but not human P2Y13 shows high affinity for IDP as well as ADP. P2Y11 is not included here because it is not expressed in rodents. (See [10, 37–39]).

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