Immobilization stress elevates intron-containing transcripts for tyrosine hydroxylase in rat superior cervical...

While both the adrenal medulla and sympathetic nervous system are important in mediating the catecholaminergic response to stress, there are crucial differences in the mechanism. Stress elevates tyrosine hydroxylase (TH) protein and mRNA levels in both the adrenal medulla and sympathetic ganglia. In the adrenal medulla, transcription of the TH gene is rapidly induced with immobilization (IMO) stress. Here, we examine whether IMO also increases TH transcription in the superior cervical ganglia (SCG). Quantitative real-time reverse transcription polymerase chain reaction was used to determine the changes in TH mRNA and in transcripts containing intron 2. As expected in the adrenal medulla following repeated IMO TH mRNA and intron containing transcripts were elevated about 5-fold. In the SCG, a significant increase in TH mRNA was observed following repeated 2 h IMO for 2 or 6 days, but not with single IMO. The intron 2 containing transcripts were elevated about 50% above controls with even single IMO, and were at similarly elevated levels after the 2nd or 6th repeated daily IMO. The results indicate, for the first time, that transcriptional mechanisms are involved in mediating the IMO stress triggered elevation in TH gene expression in the SCG.