During development and in the adult, ciliary neurotrophic factor (CNTF) is expressed at high levels in the olfactory system. In the present study, we asked whether neonatal rat olfactory ensheathing cells (OECs) express CNTF- and CNTF receptoralpha (CNTFRalpha)-mRNA in vitro and studied the regulation of both transcripts in response to growth factor and forskolin (FSK) treatment. We show here that OECs in vitro express CNTF and CNTFRalpha-mRNA under control conditions. Administration of FSK increased the expression of CNTFRalpha while lowering the levels of CNTF. Contrary to fibroblast growth factor-2, CNTF did not stimulate the proliferation of OECs. The observation that OECs express both the ligand and part of its receptor complex may indicate that CNTF exerts paracrine and/or autocrine effects in vivo, which apparently do not include the regulation of cell division.