Molecular Events in the Spinal Cord Following Sensory Stimulation

Abstract

The proto-oncogene c-fos belongs to a class of genes which is rapidly activated in fibroblast and peripheral neuronal cell lines following various forms of stimulation. Of particular relevance are the observations that c-fos transcription in PC 12 cells followed minutes after stimulation by incubation with either nerve growth factor (Curran and Morgan, 1985, Greenberg et al., 1985, Kruijer et al., 1985, Milbrandt, 1986) or with second messenger candidates such as cAMP, or depolarisation with high potassium concentrations (Greenberg and Ziff, 1984) sufficient to activate voltage-dependent calcium channels (Morgan and Curran, 1986), or with incubation with acetylcholine (Greenberg et al., 1986). It was suggested that c-fos induction could be related to the establishment of long-term changes in the central nervous system (Berridge, 1986, Goelet et al., 1986). However, attempts to correlate c-fos expression with long-term potentiation in the hippocampus or with controlled synaptic stimulation within the forebrain proved negative (Bliss et al., 1988). Expression of the protein was demonstrated only by relatively extreme procedures such as treatment with convulsant drugs or direct electrical stimulation (Morgan et al., 1987, Dragunow and Robertson, 1987, Bliss et al., 1988, Kaczmarek et al., 1988).