GENE EXPRESSION OF PROSTACYCLIN RECEPTOR IN THE HYPERTROPHIED HEART OF SPONTANEOUSLY HYPERTENSIVE RATS

1. Prostacyclin elicits potent vasodilation and inhibition of platelet aggregation through binding to its membrane receptor. The impairment of prostacyclin receptor activity is implicated in various human cardiovascular diseases. We recently succeeded in molecular cloning of cDNA for the mouse, rat, and human prostacyclin receptors. 2. In the present study, we examined the mRNA expression of the prostacyclin receptor in various rat tissues, and further investigated its gene expression in the hypertrophied cardiac ventricles of stroke‐prone spontaneously hypertensive rats (SHRSP). 3. In rat tissues, a single RNA band of approximately 3.7 kb was detected by northern blotting analysis using rat prostacyclin receptor cDNA as a probe. In adult Wistar rats, abundant mRNA expression was observed in the aorta, lung and spleen. Substantial amounts of transcript were expressed in the heart, pancreas, thymus and stomach. In contrast, no mRNA expression was detected in the brain. 4. We further examined the mRNA expression of the prostacyclin receptor in the ventricles of 21 week old SHRSP. The ventricles of SHRSP showed remarkable hypertrophy, compared with those of age‐matched Wistar‐Kyoto (WKY) rats. The expression of prostacyclin receptor mRNA in the hypertrophied ventricles of SHRSP was almost equivalent to that in the ventricles of WKY. 5. The present study revealed the gene expression of the prostacyclin receptor in various rat tissues, and further demonstrated the receptor mRNA expression in hypertensive cardiac hypertrophy. The present study will give a clue to investigate the clinical implication of prostacyclin and its receptor.