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- Title
SHUJI ARIMA, SADAYOSHI ITO, KEN OMATA, KAzuo TSUNODA, HIRAKU YAOITA, and KEISHI ABE Diverse effects of calcium antagonists on glomerular hemodynamics.
- Authors
Arima, Shuji; Ito, Sadayoshi; Omata, Ken; Tsunoda, Kazuo; Yaoita, Hiraku; Abe, Keishi
- Abstract
This study examined the direct effects of calcium antagonists on glomerular hemodynamics. Rabbit afferent (Af-) or efferent arterioles (Ef-Arts) were microperfused in vitro at constant pressure. Ef-Arts were perfused from the distal end of Af-Art through the glomerulus. Increasing doses (10-10 to 10-7 M) of nifedipine (Nif), nicardipine (Nic) or manidipine (Man) were added into the lumen of Af- or Ef-Arts preconstricted (by about 40%) with norepinephrine. Although Nif and Nic dilated Af-Arts in a dose-dependent manner, they did not cause any dilation in Ef-Arts. In contrast, Man dilated both Af- and Ef-Arts in a dose dependent manner; Man at 10-7 M dilated Af- and Ef-Arts by 71 ± 12% (N = 7) and 38 ± 3% (N = 6), respectively. Although Man's dilator effect on Ef-Art was not affected by inhibiting nitric oxide (NO) synthesis (N = 6), it was markedly attenuated by eliminating the influence of glomerulus (14 ± 3% by Man at 10-7 M, N = 5). These results demonstrate that in addition to dilating Af-Art, Man, but not Nif or Nic, dilates Ef-Art through a glomerulus-derived vasodilator(s) other than NO. Such diverse actions should be taken into consideration when calcium antagonists are used in the treatment of patients with cardiovascular and renal diseases.
- Subjects
CALCIUM antagonists; HEMODYNAMICS; KIDNEY glomerulus; NIFEDIPINE; NORADRENALINE
- Publication
Kidney International, 1996, Vol 49, pS132
- ISSN
0085-2538
- Publication type
Article