Ciliary neurotrophic factor induces preprotachykinin A gene expression in the rat carotid body

Substance P (SP), a translational product of preprotachykinin-A (PPT-A) mRN A plays an important role in hypoxic chemotransmission in the rat carotid b ody, Although hypoxic exposure has been associated with an increase in SP c ontent in the carotid body, factors that cause induction, regulation and re lease of PPT-A and SP in the carotid body remain to be elucidated. The purp ose of this study was to investigate whether ciliary neurotrophic factor (C NTF), a factor that has been shown to regulate neurotransmitter phenotype i n tissue from neural crest origin, could induce PPT-A gene expression in th e rat carotid body. We used in situ hybridization histochemistry with radio active ribonucleotide probes to investigate the effect of CNTF on PPT-A gen e induction in the carotid body. Exposure of the rat superior cervical gang lia and carotid body to increasing concentrations of CNTF in culture result ed in up-regulation and induction of PPT-A mRNA, respectively. (C) 2001 Els evier Science Ireland Ltd. All rights reserved.