Radioautographic study of benidipine hydrochloride. Localization in the mesenteric artery of spontaneously hypertensive rat
Suzuki, K.; Imada, T.; Gao, F.; Ma, H.; Nagata, T.
Arzneimittel-Forschung 44(2): 129-133
1994
ISSN/ISBN: 0004-4172 PMID: 8147944 Document Number: 433891
Microradioautographic study of (3H)-benidipine hydrochloride (KW-3049, CAS 91599-74-5) and nitrendipine (CAS 39562-70-4) localization was performed in the supramesenteric arteries of the spontaneously hypertensive rats (SHR) at 10 and 30 min after intravenous administration or in vitro incubation. The distribution of silver grains was observed by light and electron microscopy and the number of grains was counted in the tunicae intima, media and adventitia of the arteries. Areas of the correlated part of the artery were measured and the grain count per area was calculated. The grain count of (3H)-benidipine hydrochloride showed almost uniform distribution in the tunicae intima and media, which was compared at 10 and 30 min after the administration both in the in vivo and in the in vitro studies. The grain density of (3H)-nitrendipine to the tunicae intima and media increased time-dependently. Electron microscopic observation revealed that the fine distribution of (3H)-benidipine hydrochloride was mainly localized on the plasma membrane and on the cytoplasm of the cellular components of the mesenteric artery. The result suggested that the distribution of (3H)-benidipine hydrochloride was related to its pharmacologically active site, i.e. plasma membrane of the tunica intima and the smooth muscle cells of the tunica media.