Effects of ethanol and ipsapirone on the development of midline raphe glial cells and astrocytes

Previously, results of studies from our laboratory have shown that the offspring of ethanol-fed female rats have a significant decrease in serotonin (5-HT) neurons and glia that contain S100B, an essential trophic factor for the development of 5-HT neurons. The deficiency of S100B-immunopositive glia was detected during the vulnerable period in 5-HT neuron development and in brain areas proximal to these neurons. The reductions of both 5-HT neurons and S100B-positive glia were prevented by maternal treatment with a 5-HT 1A agonist (i.e., ipsapirone or buspirone). In the current study, we investigated whether the offspring of ethanol-fed rats had a general decrease in the density of glial cells in the brain areas that contain 5-HT neurons, and we determined whether these changes were prevented by maternal treatment with ipsapirone between gestational days (GDs) 13 and 20. We estimated the density of vimentin-positive glia of the midline raphe glial structure (MRGS) at GD 20 and postnatal day (PND) 5 and of glial fibrillary acidic protein (GFAP)–positive astrocytes proximal to the dorsal and median raphe at PNDs 5 and 19. The results of this study provide evidence that in utero ethanol exposure is associated with a reduced density of GFAP-immunopositive astrocytes proximal to the dorsal and median raphe. Maternal ipsapirone treatment significantly increased astroglial density in the dorsal raphe at PNDs 5 and 19 and in the median raphe at PND 5, such that it either prevented (dorsal raphe, PNDs 5 and 19) or blunted (median raphe, PND 5) the effects of ethanol.