The effect of δ-opioid agonists on intracellular calcium level in MOLT-4 T-cell line

• Published in: International journal of immunopathology and pharmacology Vol. 12; no. 3; pp. 113 - 119
• Main Authors: Martin - Kleiner, I, Gabrilovac, J
• Format: Journal Article
• Language: English
• Published: England 01.09.1999
• Subjects: calcium; d-opioid agonists
• ISSN: 0394-6320; 2058-7384
• DOI: 10.1177/205873929901200301

δ-opioid agonists were reported to affect T cell functions: proliferation, cytotoxicity, cytokine production. Changes in intracellular calcium level are important in T-cell activation. In this study the effect of the synthetic δ-opioid agonist DADLE and an endogenous δ-opioid pentapeptide Met-enkephalin on the intracellular calcium level in human T-lymphoblastic leukemia MOLT-4 cells is reported. Intracellular calcium level was monitored using QUIN 2-AM as a fluorescent dye in MOLT-4 cells after short treatment (2 and 15 min) with DADLE and Met-enkephalin. DADLE (10 M) mildly (average 28%) decreased the intracellular calcium level after 1 min treatment. The suppressive effect of DADLE (10 M) on the intracellular calcium level was enhanced by longer (15 min) treatment of MOLT-4 cells (average 40%). Met-enkephalin (10 M - 10 M) decreased (average 33 %) the intracellular calcium level after 2 min treatment (average 33% - 37%). However, Met-enkephalin (10 M) increased (average 31%) the intracellular calcium level after longer (15 min) treatment. Ionophore A23187 (10 M, 10 M) was used as a positive control to enhance intracellular calcium level. Thus, δ-opioid agonist DADLE decreased basal intracellular calcium level in MOLT-4 cells after short treatment, while endogenous Met-enkephalin altered intracellular calcium level in a bidirectional way by decreasing and increasing it.