[Effects of opioids on Ca2+ flux of polymorphonuclear leukocytes].
The effects of opioids on Ca2+ influx were evaluated using rat polymorphonuclear leukocytes, comparing with those of nicardipine and TMB-8, 8-(N, N diethyl amino) 3, 4, 5 trimethoxybenzoate. Selective opioid kappa-agonist, U-50488H, inhibited Ca2+ influx caused by f-Met-Leu-Phe (fMLP). U-50488H also strongly inhibited the elevation of intracellular free Ca2+ concentration in Ca2+ free medium. In contrast, mu-agonist, morphine showed no effects. The purified enantiomers of U-50488H exerted no difference in their effects on Ca2+ mobilization of PMNs, and naloxone did not antagonize the effects of U-50488H. Both nicardipine and TMB-8 inhibited the Ca2+ flux. The inhibitory effects of TMB-8 were potentiated by lowering extracellular free Ca2+. These results suggest that U-50488H may interfere with the Ca2+ regulatory system of PMNs via opioid receptor non-mediated pathway. The effect was suspected to be caused by selective inhibition of Ca2+ release from intracellular Ca2+ store sites by affecting post-receptor mechanisms of f-MLP.
Katoh
H
H
Department of Anesthesiology, Chubu Rosai Hospital, Nagoya.
Nakashima
M
M
Nozaki
M
M
Tsurumi
K
K
Yamamoto
M
M
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D009529:Nicardipine / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats
D000700:Analgesics; D002121:Calcium Channel Blockers; D011759:Pyrrolidines; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D009240:N-Formylmethionine Leucyl-Phenylalanine; D005707:Gallic Acid; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D009529:Nicardipine; D002118:Calcium