TY - JOUR
T1 - CO2-induced c-Fos expression in brainstem preprotachykinin mRNA containing neurons
AU - Pete, Gina
AU - Mack, Serdia O.
AU - Haxhiu, Musa A.
AU - Walbaum, Simon
AU - Gauda, Estelle B.
N1 - Funding Information:
This work was supported by National Institutes of Health Grants IU 54 NS 39407 (National Institute of Neurological Disorders and National Center for Research Resources), HL-50527, and DA-013940. We thank Cecily Lewis for secretarial support.
PY - 2002
Y1 - 2002
N2 - Tachykinin peptides are found in brainstem regions involved in central chemoreception and they may play a modulatory role in ventilatory response to hypercapnia. We determined whether tachykinin peptide containing neurons are activated by CO2 by combining in situ hybridization and immunohistochemistry (IHH). Experiments were performed in 21-day-old rats exposed to 12% CO2 for 1 h. c-Fos expression was identified by IHH on free floating sections (40 μm) that were mounted and then hybridized with anti-sense 35S labeled ribonucleotide probe of the rat preprotachykinin A (PPT-A) gene. Sections were analyzed for expression of the PPT-A gene, c-Fos protein and colocalization of PPT-A gene with c-Fos protein. Within the chemosensory region of the nucleus tractus solitarius (nTS), 19% of c-Fos positive cells expressed PPT-A mRNA after hypercapnic loading. In medullary raphe nuclei, 64% of c-Fos positive cells expressed the PPT-A gene after exposure to CO2, while 21% of c-Fos labeled neurons in parapyramidal nuclei also expressed PPT-A mRNA. These results indicate that a subpopulation of CO2 activated neurons within the nTS and in the parapyramidal and midline regions of the ventral aspect of the medulla oblongata express the PPT-A gene, suggesting that these are substance P- or neurokinin A-containing neurons. Furthermore, these peptides may play a role in modulation of respiratory and cardiovascular responses to changes in CO2/H+ content of the extracellular fluid.
AB - Tachykinin peptides are found in brainstem regions involved in central chemoreception and they may play a modulatory role in ventilatory response to hypercapnia. We determined whether tachykinin peptide containing neurons are activated by CO2 by combining in situ hybridization and immunohistochemistry (IHH). Experiments were performed in 21-day-old rats exposed to 12% CO2 for 1 h. c-Fos expression was identified by IHH on free floating sections (40 μm) that were mounted and then hybridized with anti-sense 35S labeled ribonucleotide probe of the rat preprotachykinin A (PPT-A) gene. Sections were analyzed for expression of the PPT-A gene, c-Fos protein and colocalization of PPT-A gene with c-Fos protein. Within the chemosensory region of the nucleus tractus solitarius (nTS), 19% of c-Fos positive cells expressed PPT-A mRNA after hypercapnic loading. In medullary raphe nuclei, 64% of c-Fos positive cells expressed the PPT-A gene after exposure to CO2, while 21% of c-Fos labeled neurons in parapyramidal nuclei also expressed PPT-A mRNA. These results indicate that a subpopulation of CO2 activated neurons within the nTS and in the parapyramidal and midline regions of the ventral aspect of the medulla oblongata express the PPT-A gene, suggesting that these are substance P- or neurokinin A-containing neurons. Furthermore, these peptides may play a role in modulation of respiratory and cardiovascular responses to changes in CO2/H+ content of the extracellular fluid.
KW - Control of breathing, c-Fos expression
KW - Mammals, rat
KW - Mediators, neurokinin A, substance P
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U2 - 10.1016/S0034-5687(02)00013-0
DO - 10.1016/S0034-5687(02)00013-0
M3 - Article
C2 - 12093623
AN - SCOPUS:0036327435
SN - 1569-9048
VL - 130
SP - 265
EP - 274
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 3
ER -