DDE-I RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM OF THE ALPHA-2-ADRENOCEPTOR GENE DOES NOT CORRELATE WITH BLOOD-PRESSURE IN THE F2 GENERATIONOBTAINED FROM CROSSING STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS AND WISTAR-KYOTO RATS

Objective: A pathogenetic role of altered alpha(2)-adrenoceptors in es sential hypertension has been suggested, based on studies in humans an d animals. To examine the role of the alpha(2)-adrenoceptor in genetic ally hypertensive rats, we compared the alpha(2)-adrenoceptor genes of stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto (WKY) rats by restriction fragment length polymorphism analysis using human alpha(2)-adrenoceptor probes (alpha(2)-C10) and Dde I restricti on endonuclease, and conducted a genetic cosegregation study. Method: Five female WKY rats were bred with five male SHRSP. Eight pairs of F- 1 Fats were mated in brother-sister pairs to yield an F-2 population o f 84 rats. Systolic blood pressure was determined by tail-cuff sphygmo manometry. Direct arterial blood pressure was taken under ether anaest hesia just before the rats were killed. Southern blots were performed using alpha(2)C10 as a probe and the DNA from the F-2 generation. Resu lts: A restriction fragment length polymorphism of the SHRSP allele of a 1.6-kb fragment and a WKY rat allele oi a 0.9-kb fragment with a co mmon band of 1.3 kb in SHRSP and WKY rats was found, as reported previ ously. The distribution of the genotype based on restriction fragment length polymorphism conformed to a 1:2:1 ratio in F-2 rats, as expecte d for a Mendelian trait. There was no significant difference in the bl ood pressure of F-2 rats with respect to alpha(2)-adrenoceptor genotyp e. Conclusion: This study demonstrated that the alpha(2)-adrenoceptor gene restriction fragment length polymorphism distribution is a Mendel ian trait in the F-2 rats of crossed SHRSP and WKY rats, but failed to show genetic cosegregation of this restriction fragment length polymo rphism with blood pressure in this generation.