Fig. 1.

Expression of CRF receptors in the rat esophagus and LES. RT-PCR analysis was performed to detect the presence of CRF receptor transcripts in the distal esophagus (Eso) and LES cDNAs synthesized with (+) or without reverse transcriptase (–RT) of normal rats using specific oligonucleotide primers (shown in Table 1) to amplify amino-terminal coding sequences, which differentiate receptor subtypes and two major CRF₂ splice variants, 2a and 2b. Brain cerebral cortex (BC), hypothalamus (Hyp), and heart ventricle (HV) were used as positive controls (Pos.) for CRF₁, CRF_2a, and CRF_2b, respectively. Predicted CRF₁ (433 bp), CRF_2a (353 bp), and CRF_2b (201 bp) and an unpredicted CRF_2a variant (CRF_2a-3, 483 bp) were indicated by arrows next to their respective panels (A–D). Real-time PCR was performed to measure relative abundance of CRF₁ and CRF₂ using the same samples. Data were calculated by 2^−ΔΔCt method and expressed as mean ± sd of triplicate determinations from two separate experiments normalized to the internal GAPDH and positive controls, which has a mean relative mRNA level of 1.0 (E).