Ion channel interactions of P2Y receptors Data derived from Filippov et al. (1998, 1999, 2000, 2003, 2004); Brown et al. (2000a); and Simon et al. (2002).
| P2Y | Ca2+ Channel Closure | K(M) Channela | GIRKa | |||||
|---|---|---|---|---|---|---|---|---|
| Whole Cell | Perf.a | PTX Blockb | G Proteinc | Closure | G Proteind | Activation | G Protein | |
| % | ||||||||
| 1 | Yese | ∼50 | αq/11+βγ (Gq + Go) | Yese | αq/11 | Yese,f | βγ | |
| 2 | Yes | ∼60 | αq/11+βγ (Gq + Go) | Yes | αq/11 | Yesf | βγ | |
| 4 | No | Weak | ∼80a | βγ (Go)a | Yes | αq/11 | No | |
| 6 | Yes | Yes | ∼0a | αq/11+βγ (Gq)a | Yes | αq/11 | No | |
| 12 | Yes | 100 | βγ (Gi/o) | No | Yesf | βγ | ||
K(M) channel, M-current K+ channel; GIRK, G protein-activated inwardly rectifying K+ channels
↵ a Determined in perforated patch recording (Perf.), which avoids possible dialysis of some soluble cell components
↵ b The percentage of the N-type Ca2+ current inhibition by P2Y action, which is blocked by PTX pre-treatment
↵ c The G protein subunits which are proposed to act at N-type Ca2+ channels; in parentheses are the parent heterotrimeric G proteins deduced to provide the βγ subunits involved, this being noted only for the perforated patch state in which that is used; involvement of βγ (where tested) was stated by showing total prevention of channel closure by coexpressing excess Gα transducin
↵ d The G protein subunit found to act at M-current K+ channels
↵ e `Yes' denotes that the induced change occurs with agonist potencies similar to or greater than those known for other transductions of this receptor. `No' denotes that the induced charge is essentially absent; `Weak' denotes that the induced charge occurs but at greatly reduced agonist potency
↵ f Highly sensitive to PTX pretreatment