Pharmacological Characterization of the Mechanisms Involved in Delayed Calcium Deregulation in SH-SY5Y Cells Challenged with Methadone.
Previously, we have shown that SH-SY5Y cells exposed to high concentrations of methadone died due to a necrotic-like cell death mechanism related to delayed calcium deregulation (DCD). In this study, we show that, in terms of their Ca(2+) responses to 0.5 mM methadone, SH-SY5Y cells can be pooled into four different groups. In a broad pharmacological survey, the relevance of different Ca(2+)-related mechanisms on methadone-induced DCD was investigated including extracellular calcium, L-type Ca(2+) channels, μ-opioid receptor, mitochondrial inner membrane potential, mitochondrial ATP synthesis, mitochondrial Ca(2+)/2Na(+)-exchanger, reactive oxygen species, and mitochondrial permeability transition. Only those compounds targeting mitochondria such as oligomycin, FCCP, CGP 37157, and cyclosporine A were able to amend methadone-induced Ca(2+) dyshomeostasis suggesting that methadone induces DCD by modulating the ability of mitochondria to handle Ca(2+). Consistently, mitochondria became dramatically shorter and rounder in the presence of methadone. Furthermore, analysis of oxygen uptake by isolated rat liver mitochondria suggested that methadone affected mitochondrial Ca(2+) uptake in a respiratory substrate-dependent way. We conclude that methadone causes failure of intracellular Ca(2+) homeostasis, and this effect is associated with morphological and functional changes of mitochondria. Likely, this mechanism contributes to degenerative side effects associated with methadone treatment.
Neuropharmacology, Department of Medical Sciences, School of Medicine, University of Castilla-La Mancha (UCLM), 02006 Albacete, Spain.
Sergio
S
Perez-Alvarez
Maria E
ME
Solesio
Maria D
MD
Cuenca-Lopez
Raquel M
RM
Melero-Fernández de Mera
Carlos
C
Villalobos
Hanna
H
Kmita
Maria F
MF
Galindo
Joaquin
J
Jordán