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DECREASED SENSITIVITY TO β‐ADRENERGIC STIMULATION OF THE VENTRICULAR CELLS ISOLATED FROM THE SPONTANEOUSLY HYPERTENSIVE RAT HEART
Author(s) -
Habuchi Yoshizumi,
Lu LingLing,
Okamoto Shigetaka,
Komori Toshiaki,
Takahashi Hakuo,
Morikawa Junichiro,
Yoshimura Manabu
Publication year - 1995
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1995.tb02840.x
Subject(s) - ibmx , medicine , endocrinology , stimulation , phosphodiesterase inhibitor , phosphodiesterase , spontaneously hypertensive rat , heart rate , chemistry , patch clamp , adrenergic , isoprenaline , electrophysiology , blood pressure , enzyme , receptor , forskolin , biochemistry
Summary 1. The stirnulatory effects of isoproterenol on the L‐type Ca 2+ current (Ic.) were compared between the control (WKY) and hypertensive (SHR) rat heart cells, using the patch‐clamp method. 2. The current density and the shape of the current‐voltage relationship for Ic. were not different between the two groups. However, the maximal percentage increase in response to isoproterenol was smaller in SHR (+ 91% in SHR and + 81% in WKY), and the ED 50 was significantly higher in SHR (0.081 μmol/L in SHR and 0.020 μmol/L in WKY). IBMX, a potent phosphodiesterase inhibitor, significantly increased the isoproterenol‐stimulated Ica in SHR, but not in WKY. These results suggest an impaired CAMP production in SHR heart cells.