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Mu‐ and delta‐opioid receptor antagonists decrease proliferation and increase neurogenesis in cultures of rat adult hippocampal progenitors
Author(s) -
Persson Anders I.,
Thorlin Thorleif,
Bull Cecilia,
Zarnegar Parisa,
Ekman Rolf,
Terenius Lars,
Eriksson Peter S.
Publication year - 2003
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2003.02538.x
Subject(s) - naltrindole , neurogenesis , (+) naloxone , hippocampal formation , progenitor cell , receptor , microbiology and biotechnology , opioid , κ opioid receptor , δ opioid receptor , chemistry , opioid receptor , medicine , endocrinology , biology , stem cell , biochemistry
Opioids have previously been shown to affect proliferation and differentiation in various neural cell types. In the present study, cultured rat adult hippocampal progenitors (AHPs) were shown to release β‐endorphin. Membrane preparations of AHPs were found to bind [ 125 I]β‐endorphin, and immunoreactivity for mu‐ and delta‐opioid receptors (MORs and DORs), but not for kappa‐opioid receptors (KORs), was found on cells in culture. Both DNA content and [ 3 H]thymidine incorporation were reduced after a 48‐h incubation with 100 µ m naloxone, 10 µ m naltrindole or 10 µ m β‐funaltrexamine, but not nor‐binaltorphimine, suggesting proliferative actions of endogenous opioids against MORs and DORs on AHPs. Furthermore, analysis of gene and protein expression after incubation with MOR and DOR antagonists for 48 h using RT‐PCR and Western blotting suggested decreased signalling through the mitogen‐activated protein kinase (MAPK) pathway and lowered levels of genes and proteins that are important in cell cycling. Cultures were incubated with naloxone (10 or 100 µ m ) for 10 days to study the effects on differentiation. This resulted in an approximately threefold increase in neurogenesis, a threefold decrease in astrogliogenesis and a 50% decrease in oligodendrogenesis. In conclusion, this study suggests that reduced signalling through MORs and DORs decreases proliferation in rat AHPs, increases the number of in vitro ‐generated neurons and reduces the number of astrocytes and oligodendrocytes in culture.