Mobilization of calcium from intracellular store as a possible mechanism underlying the anti-opioid effect of angiotensin II.
Angiotensin II (AII), injected intracerebroventricularly, has been shown to antagonize opioid analgesia. The mechanism for this was obscure. In the neuroblastoma X glioma NG 108-15 hybrid cell line, the K(+)-induced increase in [Ca2+]i can be suppressed by the delta opioid agonist [D-Pen2, D-Pen5]enkephalin (DPDPE) at 0.01-1 microM, an effect completely reversed by the opioid antagonist naloxone. Angiotensin II (AII) at concentrations of 0.1 and 1 microM mobilized free Ca2+ from an intracellular pool, and this effect was antagonized by the AII receptor antagonist saralasin. All (1 microM) had no significant effect on the increase in [Ca2+]i induced by K+, but it blocked the suppressive effect of DPDPE on the K(+)-induced [Ca2+]i increase. The results indicate that mobilization of intracellular calcium may underlie the anti-opioid effect of AII.
Wang
J F
JF
Department of Physiology, Beijing Medical University, P.R. China.
Sun
X J
XJ
Yang
H F
HF
Ren
M F
MF
Han
J S
JS
D000804:Angiotensin II / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D004723:Endorphins / Q000037:antagonists & inhibitors*; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009447:Neuroblastoma / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D012504:Saralasin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D004723:Endorphins; D004745:Enkephalins; D000804:Angiotensin II; D009270:Naloxone; D011189:Potassium Chloride; D020881:Enkephalin, D-Penicillamine (2,5)-; D012504:Saralasin; D002118:Calcium