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Expression of C ‐ fos ‐like protein as a marker for neuronal activity following noxious stimulation in the rat
Author(s) -
Bullitt Elizabeth
Publication year - 1990
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.902960402
Subject(s) - c fos , stimulation , brainstem , noxious stimulus , premovement neuronal activity , neuroscience , immediate early gene , biology , electrophysiology , medulla oblongata , nucleus , medicine , endocrinology , central nervous system , nociception , gene expression , gene , biochemistry , receptor
C ‐ fos is a proto‐oncogene that is expressed within some neurons following depolarization. The protein product, c ‐ fos protein, can be identified by immunohistochemical techniques. Therefore, c ‐ fos expression might be used as a marker for neuronal activity throughout the neuraxis following peripheral stimulation. This study has analyzed patterns of c ‐ fos expression in both control and anesthetized animals and in anesthetized rats subjected to various forms of peripheral stimulation. Labeled cells were counted in the spinal cord, brainstem, hypothalamus, and thalamus. Little c ‐ fos immunoreactivity was found in control animals. Prolonged inhalational anesthesia increased the number of labeled cells at several brainstem sites. Noxious stimulation of anesthetized rats induced c ‐ fos within the neuraxis in patterns consistent with data obtained from electrophysiological studies and in additional locations for which few direct electrophysiological data are available, such as the ventrolateral medulla, the posterior hypothalamic nucleus, and the reuniens and paraventricular thalamic nuclei. Gentle mechanical stimulation was ineffective in inducing c ‐ fos ‐like protein. The data suggest that c ‐ fos can be used as a transynaptic marker for neuronal activity following noxious stimulation. However, c ‐ fos is expressed only in some kinds of neurons following peripheral stimulation, and it therefore may be an incomplete marker for nociresponsive activity. In addition, at least a few neurons express c ‐ fos protein in the absence of noxious stimulation. Experiments analyzing c ‐ fos expression must be designed with care, as both extraneous stimuli and anesthetic depth influence the results.