Culture conditions determine the prevalence of bipolar and monopolar neurons in cultures of dissociated spiral ganglion.
To gain insight into the mechanisms that control the generation or maintenance of the characteristic bipolar morphology of cochlear spiral ganglion neurons, we have taken advantage of our recently developed procedure for culture of dissociated newborn mouse spiral ganglion. In these cultures, inclusion of the cytokine leukemia inhibitory factor (LIF) in the medium increases neuronal survival and the number of bipolar neurons. Here we tested effects of two other LIF-type cytokines (ciliary neurotrophic factor, CNTF; and human recombinant oncostatin M, hOSM) and of bone morphogenetic protein 4 (BMP4) on survival, morphology and neurite lengths of neurons in cultures of dissociated spiral ganglion. Like LIF, CNTF and hOSM increased neuronal survival and the number of surviving bipolar neurons. BMP4 also increased neuronal survival, but unlike LIF, CNTF and hOSM, increased the number of monopolar neurons and neurons with no neurites. In addition, population histograms demonstrate that the population lengths of the longer and shorter neurites of bipolar neurons were shorter in BMP4 containing cultures than in control or LIF cultures. When LIF and BMP4 were simultaneously added to the cultures, the BMP4 effects predominated. These experiments demonstrate that exposure to different environmental conditions can result in different morphologies in the surviving population of spiral ganglion neurons in culture.
Whitlon
D S
DS
Department of Otolaryngology Head and Neck Surgery, Searle, Room 12-561, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA. whitlon@northwestern.edu
Grover
M
M
Tristano
J
J
Williams
T
T
Coulson
M T
MT
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D049108:Cell Enlargement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D053605:Leukemia Inhibitory Factor / Q000494:pharmacology; D051379:Mice; D016501:Neurites / Q000187:drug effects; D009474:Neurons / Q000145:classification* / Q000166:cytology / Q000187:drug effects*; D013136:Spiral Ganglion / Q000166:cytology*; D014404:Tubulin / Q000378:metabolism
C525809:BMP4 protein, human; C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D003470:Culture Media; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D014404:Tubulin; C462941:beta3 tubulin, mouse