title: Phenotypes of ATP-activated current associated with their genotypes of P2X1-6 subunits in neurons innervating tooth-pulp.
abstract: To explore the association of the phenotype of ATP-activated current with the genotype of P2X1-6 subunits in nociceptors, we developed a method that allows us to label nociceptive neurons innervating tooth-pulp in rat trigeminal ganglion (TG) neurons using a retrograde fluorescence-tracing method, to record ATP-activated current in freshly isolated fluorescence-labeled neurons, and then to conduct single cell immunohistochemical staining for P2X1-6 subunits in the same neuron. We found that fast application of 100 μM ATP to fluorescence-traced TG neurons produced robust inward current in 87% (96/110) of cells tested. The diameter of cells varied from 16 to 56 μm. Three types of ATP-activated current (F, I and S) were recorded with distinct rise times of the current (R10-90, P < 0.05). There was a positive correlation between the cell diameter and the value of R10-90 (P < 0.05): the value of R10-90 increased with increases in the cell diameter. Cells responsive to ATP with the type F current mainly showed positive staining for P2X3 and P2X5, but negative staining for P2X2; cells responsive to ATP with the type I current showed positive staining for P2X1-3 and P2X5, but negative staining for P2X4; and cells responsive to ATP with the type S current showed positive staining for P2X1-5, but negative staining for P2X6. The present findings suggest that in addition to P2X3 subunits, P2X5 subunits are also involved in the generation of the F type of ATP-activated current in small-sized nociceptive neurons. In addition to the P2X2/3 subunit-containing channels, more complex uncharacterized combinations of P2X1-5 subunits exist in native medium-sized nociceptive neurons exhibiting the I and S types of ATP-activated current. In addition, the P2X6 subunit is not a main subunit involved in the nociceptive signal in rat TG neurons innervating tooth-pulp.
authors: Wuhan Institutes of Biomedical Sciences, Jianghan University, Wuhan, 430056, Hubei Province, China; School of Medicine, Jianghan University, Wuhan, 430056, China.
authors: Yuwei
authors: Y
authors: Liu
authors: Wuhan Institutes of Biomedical Sciences, Jianghan University, Wuhan, 430056, Hubei Province, China.
authors: Xiang
authors: X
authors: Tian
authors: Wuhan Institutes of Biomedical Sciences, Jianghan University, Wuhan, 430056, Hubei Province, China.
authors: Yuxiang
authors: Y
authors: Wu
authors: Wuhan Institutes of Biomedical Sciences, Jianghan University, Wuhan, 430056, Hubei Province, China.
authors: Lin
authors: L
authors: Chen
authors: School of Medicine, Jianghan University, Wuhan, 430056, China.
authors: Chu-Li
authors: CL
authors: Yi
authors: Wuhan Institutes of Biomedical Sciences, Jianghan University, Wuhan, 430056, Hubei Province, China.
authors: Zhi-Wang
authors: ZW
authors: Li
authors: Wuhan Institutes of Biomedical Sciences, Jianghan University, Wuhan, 430056, Hubei Province, China.
authors: Ying
authors: Y
authors: Zhang
authors: Wuhan Institutes of Biomedical Sciences, Jianghan University, Wuhan, 430056, Hubei Province, China. Electronic address: licy.whibs@aliyun.com.
authors: Chao-Ying
authors: CY
authors: Li
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D003782:Dental Pulp / Q000294:innervation*; D005838:Genotype; D007150:Immunohistochemistry; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D058469:Receptors, Purinergic P2X / Q000235:genetics / Q000378:metabolism*; D012668:Trigeminal Ganglion / Q000166:cytology
chemical_list: D021122:Protein Subunits; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; C110590:purinoceptor P2X6; D000255:Adenosine Triphosphate
keywords: Immunohistochemistry; P2X; Retrograde fluorescence-tracing; Tooth-pulp; Trigeminal ganglion