[Effect of G protein in the dual regulation of opioid receptor agonist on the delayed rectified potassium channels].
OBJECTIVE
To observe the role of G protein in the dual regulation of opioid receptor agonist on the delayed rectified potassium channels.


METHODS
Using whole-cell patch-clamp techniques applied to NG108-15 cells, investigate the effect of opioid receptor agonist on the delayed rectified potassium channels by administration of Guanosine-5'-0'-2-thiociphosphate (GDP beta S), Pertusis Toxin (PTX), Tetroacetic acid nueleoside diphosphate kinase (NDPK) and Adenosine-3' 5' cyclic monophosphate cAMP in the pipette solution.


RESULTS
(1) GDP beta S could block the changes induced by both high and low concentration of (D-Pen2.5)-enkephalin (DPDPE) (P < 0.05). (2) PTX could inhibit the excitative regulation on K+ channel by high concentration of DPDPE (P < 0.05). But CTX had no effect on K+ channel caused by DPDPE. (3) UDP could block the excitative effect of K+ channel by high concentration of NDPK, while have no changes on the inhibitory effect caused by low concentration of opioid agonists. (4) cAMP took part in the regulation in high concentration of agonist administration (P < 0.05), while no changes for low concentration of agonists.


CONCLUSIONS
Dual changes were observed on delayed rectifier potassium channel by agonist treatment on NG108-15 cells. The excitative effect was Gi/o coupled in high concentration of agonist incubation, related to cAMP. While the inhibitory effect was possibly induced by G protein beta gamma subunit directly.
Ye
Cai-ying
CY
Department of Pharmacology, Institute of Basic Medical Sciences, CAMS, PUMC, Beijing 100005, China. caiying_ye@sohu.com
Li
Qing-xia
QX
Yu
Xiao-li
XL
Qi
Jing-jing
JJ
Li
Juan
J
Zhang
De-chang
DC
D000818:Animals; D020881:Enkephalin, D-Penicillamine (2,5)- / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D005910:Glioma / Q000378:metabolism / Q000473:pathology; D006157:Guanosine Monophosphate / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D006822:Hybrid Cells / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology; D018408:Patch-Clamp Techniques; D037342:Pertussis Toxin / Q000494:pharmacology; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D051381:Rats; D011957:Receptors, Opioid / Q000819:agonists*; D013873:Thionucleotides / Q000493:pharmacokinetics
D024661:Potassium Channels, Inwardly Rectifying; D011957:Receptors, Opioid; D013873:Thionucleotides; C077838:guanosine-5'-O-(S-(3-bromo-2-oxopropyl))thiophosphate; D006157:Guanosine Monophosphate; D020881:Enkephalin, D-Penicillamine (2,5)-; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins