Figure 11.

Mechanisms for the developmental increase in neuronal gap junction coupling play a role in regulation of neuronal death/survival during development. Experiments were conducted in rat hypothalamic neuronal cultures. NMDA (100 μm) was added to the culture medium on DIV14 for 60 min and then washed out. The MTT analysis of neuronal death was conducted 24 h later (on DIV15). A, NMDA administration induces neuronal death in nontreated cultures. NMDA-mediated neuronal death is augmented in cultures chronically treated (on DIV3–DIV15) with the group II mGluR agonist (LY379268) and does not occur in cultures chronically treated with the group II mGluR antagonist (LY341495). The mGluR agents by themselves do not affect cell survival. B, NMDA-mediated neuronal death also is prevented by coadministration of the gap junctional blocker carbenoxolone (CBX). In both graphs, statistical data are shown. Statistical analysis was done using ANOVA with Tukey's post hoc test relative to (a) control and (b) nontreated plus NMDA conditions (mean ± SEM); n = 6 in each group.