Oligodendroglial signal transduction systems are developmentally regulated.

Studies from several laboratories indicate that oligodendroglia exhibit signal transduction systems that can be activated by classical neurotransmitters. Previous studies from this laboratory indicate that oligodendroglia express neuroligand receptors linked to the regulation of Ca(2+)i. Experiments presented in this article were designed to determine if developmental processes that influence the ability of oligodendroglia to respond to neuroligands with an increase in Ca2+i proceed either in vitro or in vivo. Findings support the view that developmental processes markedly affected the sensitivity of these cells to both purinergic and cholinergic receptor agonists, whereas their responsiveness to either histamine or bradykinin appeared relatively stable over time. Approximately 90 and 75% of oligodendroglia responded to ATP or carbachol, respectively, after 4 days in vitro, whereas < 10% of these cells responded to either of these neuroligands after 8 days in vitro. The decrease in the percentage of oligodendroglia responding to ATP, but not carbachol, could be prevented by including dibutyryl cyclic AMP in the culture medium during the final 4 days in vitro. However, once the loss in responsiveness to ATP had occurred, it could not be reversed by exposure to dibutyryl cyclic AMP. Developmental changes in the ATP sensitivity of oligodendroglia occurred in cells expressing galactocerebroside and myelin basic protein. The neuroligand sensitivity of oligodendroglia isolated from either neonatal, 2-, 3-, or 5-week-old spinal cord was examined to determine if developmental changes in oligodendroglial Ca2+ regulation occurred in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)