BINDING OF [H-3] (-PN200-110 TO AORTIC MEMBRANES FROM NORMOTENSIVE AND SPONTANEOUSLY HYPERTENSIVE RATS())

We report here the quantitative evaluation of binding density (B-max) of [H-3](+)-PN200-110 in aortic membranes obtained from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. At b oth 4 and 13 weeks of age, there were no significant differences in B- max and the dissociation constants (K-d) of [H-3](+)-PN200-110 binding between SHR and WKY rat aortas. Irrespective of strain, the K-d incre ased and the B-max decreased with age. These results suggest that the number of Ca2+ channels in aortas of SHR and WKY rats are not signific antly different, even when hypertension is established in SHR.