Chronic nicotine treatment leads to induction of tyrosine hydroxylase in locus ceruleus neurons: the role of transcriptional activation
| Autor: | Xiqun Chen, Carol R. Sterling, A. William Tank, Baoyong Sun, Lu Xu |
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| Rok vydání: | 2004 |
| Předmět: |
Male
Transcriptional Activation medicine.medical_specialty Nicotine Tyrosine 3-Monooxygenase Stimulation Biology Primary transcript Time Rats Sprague-Dawley Internal medicine medicine Animals RNA Messenger Pharmacology Neurons Messenger RNA Tyrosine hydroxylase Reverse Transcriptase Polymerase Chain Reaction Locus Ceruleus RNA Rats medicine.anatomical_structure Endocrinology Adrenal Medulla Enzyme Induction Molecular Medicine Locus Coeruleus Adrenal medulla medicine.drug |
| Zdroj: | Molecular pharmacology. 66(4) |
| ISSN: | 0026-895X |
| Popis: | Chronic nicotine treatment (two daily subcutaneous injections administered approximately 12 h apart for 14 days) is associated with long-term inductions of tyrosine hydroxylase (TH) protein and TH mRNA in locus ceruleus (LC) neurons. These increases persist for at least 3 days after the final nicotine injection in LC cell bodies and for at least 7 to 10 days in LC nerve terminal regions. We tested whether this long-term response is due to sustained stimulation of TH gene transcription rate. A semiquantitative reverse transcription-polymerase chain reaction assay was developed to assess changes in the levels of TH RNA primary transcripts; these changes are an indirect measurement of changes in TH gene transcription rate. TH RNA primary transcript levels increase rapidly in the LC after a single nicotine administration and return to basal levels by 24 h. A similar rapid and transient induction of LC TH RNA primary transcripts occurs after chronic nicotine administration. In contrast, TH RNA primary transcript levels remain elevated for a sustained period of time (at least 1 day) in the adrenal medulla after chronic nicotine administration. Similar rapid, but transient changes in LC TH RNA primary transcript levels are observed after repeated immobilization stress. These results suggest that TH gene transcription rate in the LC is stimulated rapidly after each nicotine injection; however, in contrast to the adrenal medulla, there is no sustained transcriptional response elicited by chronic nicotine treatment or repeated immobilization stress in the LC, suggesting that post-transcriptional mechanisms may also play a role in these long-term responses. |
| Databáze: | OpenAIRE |
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