1986 Volume 28 Issue 6 Pages 807-813
Red blood cell (RBC) membrane permeability and its interaction with Ca-antagonists in spontaneously hypertensive rats (SHR) were examined and compared with those of their normotensive control Wistar-Kyoto (WKY). Oral administration of nifedipine or diltiazem in SHR resulted in marked fall of blood pressure and vasodilating action of Caantagonists seemed to reduce the hypertonic state of SHR's vessels, so interaction of the drugs with cell membrane was considered to play critical role. On the other hand, incubation of RBC with 131I-orthoiodohippurate (OIH) showed increased membrane permeability of the RBC of SHR. Inhibition of Band 3 protein, which is responsible for the anion transport of RBC membrane, with its specific inhibitors showed that free diffusion through RBC membrane is more feasible in SHR (p<0.005), because OIH enters RBC partially through carrier (Band 3 protein) -mediated anion transport system as organic anion and partially by free diffusion. OIH has a halogen binding to aromatic ring, so it is considered to be lipophilic and easy to pass through cell membrane by diffusion. Nifedipine increased permeability of RBC membrane more in SHR than in WKY (p<0.02), but diltiazem had no effect on it. It seemed likely that as nifedipine is very insoluble in water, it interacts with cell surface but diltiazem does not do so. The difference of the reaction to nifedipine between SHR's RBC and WKY's also suggests that SHR's cell membrane differs from that of WKY.
