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.