Comparison of the Distribution of C-Fos With Primary Afferent Markers

Abstract

The neuropeptides Substance P (SP) and Calcitonin gene related peptide (CGRP) were used as markers for peptidergic primary afferent fibres. A lectine, Griffonia simplicifolia (Bandeiraea simplicifolia) Isolectin-B4 (GSA I-B4), was used as a marker for non-peptidergic primary afferent fibres. C-Fos immunoreactivity was determined in the spinal cord of rats which had received 100% mustard oil application in the right hind limb. Darkly labeled c-Fos immunoreactive cells were concentrated in laminae I-IIo of the dorsal horn. SP and GSA I-B4 were distributed almost in the same regions. CGRP was more abundant in laminae I-IIo with some immunoreactive fibres in lamina IIi. These data suggest that a population of peptidergic and non-peptide primary afferents may play an important function in the induction of c-fos by mustard oil.