Expression of preproopiomelanocortin mRNA and preprodynorphin mRNA in brain of spontaneously hypertensive rats.

AIM To compare the expressions of prepropiomelanocortin (POMC) mRNA and preprodynorphin (PPD) mRNA between 16-wk-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY). METHODS The expression of POMC mRNA and PPD mRNA were detected with nonradioactive in situ hybridization by digoxigenin-labeled RNA probe. RESULTS POMC mRNA mainly was expressed in arcuate nucleus, compared with WKY, SHR had higher level of POMC mRNA (542). PPD mRNA was found in hippocampus, hypothalamus, central gray, nucleus of the solitary tract (NTS), and thoracic spinal cord (T4-T6). Compared with WKY, PPD mRNA level of SHR decreased in dentate gyrus (2342), NTS (381), and medial preoptic area (467); no difference was observed in arcuate nucleus (263), thoracic spinal cord (750-1800) and CA1, CA2, CA3 of hippocampus (1674, 2014, 2626). CONCLUSION Increase of POMC mRNA in arcuate nucleus and decrease of PPD mRNA in dentate gyrus of SHR may be associated with the genesis of spontaneous hypertension.