Age related changes in Ca2+ channels in spontaneously hypertensive rats.

The binding of the Ca2+ channel antagonist [3H]PN200 110 to 1,4-dihydropyridine binding sites in cardiac, brain and vascular smooth muscle preparations from WKY and SHR was studied as a function of age and blood pressure. 2. Binding site density in the heart from prehypertensive SHR (6 weeks) was significantly lower than that of WKY. 3. Between 6 and 12 weeks binding site density in SHR increased and between 12 and 24 weeks there was no difference between WKY and SHR. No changes in affinity occurred. 4. In brain a significant fall in binding site density occurred between 6 and 12 weeks and there was (with limited data) an increase in binding site density in tail artery membranes. 5. A good correlation (r = 0.82) exists between blood pressure and cardiac binding site density between 6 and 12 weeks of age in SHR.