Actions of nipradilol (K-351), a new .ALPHA.- and .BETA.-adrenoceptor blocker, on the rabbit portal vein.
スポンサーリンク
概要
- 論文の詳細を見る
Nipradilol but not desnitro nipradilol ((N-) nipradilol) inhibited the norepinephrine (NE) -induced depolarization and contraction of the rabbit portal vein. The NE-induced contraction and depolarization were also blocked by prazosin, but not blocked by yohimbine. Therefore, nipradilol possesses an α<SUB>1</SUB>-blocking action. The order of potency was prazosin >nipradilol >yohimbine> (N-) - nipradilol=0. With applications of field stimulations to muscle tissues, the smooth muscle membrane was depolarized with a latency of several seconds, and the action potential was generated. These phenomena were blocked by tetrodotoxin (TTX), prazosin or nipradilol, but not by yohimbine. Isoproterenol (Isop) inhibited the 30 mM K-induced contraction, and this inhibitory action was blocked by (N-), nipradilol, nipradilol or propranolol, dose-dependently. The potency of β-blocking actions of nipradilol was much the same as that observed by propranolol and (N-) nipradilol. When nipradilol (10<SUP>-5</SUP> M) was applied to the tissue, the amplitude of the 30 mM K contraction was slightly reduced. Such inhibitory action was not observed by application of (N-) nipradilol. The K<SUB>1</SUB> values of nipradilol for blocking actions on the NE-induced contraction and Isop-induced relaxation were of the same order of 10<SUP>-7</SUP> M. Therefore, the potencies of α<SUB>1</SUB> -blocking and β-blocking actions of nipradilol may be the same in the rabbit portal vein. These findings suggest that the vasodilating action of nipradilol on the rabbit portal vein is mainly due to the α<SUB>1</SUB>-blocking action and that the nitrate action of this agent may be weak.
- 公益社団法人 日本薬理学会の論文
著者
-
Kitamura Kenji
Department Of Chemical Engineering Faculty Of Engineering Kyoto University
-
NANJO Tamaki
Department of Pharmacology, Faculty of Medicine, Kyushu University
-
KITAMURA Kenji
Department of Pharmacology, Faculty of Medicine, Kyushu University
関連論文
- Tarantula Toxin ProTx-I Differentiates Between Human T-type Voltage-Gated Ca2+ Channels Cav3.1 and Cav3.2
- PHARMACOKINETICS AND CLINICAL EFFECTS OF CEFOZOPRAN IN PEDIATRIC PATIENTS
- Effects of Flufenamic Acid on Smooth Muscle of the Carotid Artery Isolated from Spontaneously Hypertensive Rats
- L-Arginine-induced current in portal venous smooth muscle cells
- Involvement of P/Q-type Voltage-dependent Calcium Channels in the Streptozotocin-induced Hyperalgesia in Mice
- Clinical features of measles in immunocompromised children
- State-Dependent Inhibition of L-type Ca^ Channels in A7r5 Cells by Cilnidipine and Its Derivatives
- Clonidine induced endothelium-dependent tonic contraction in circular muscle of the rat hepatic portal vein
- Evidence for the involvement of the cyclooxygenase-metabolic pathway in diclofenac-induced inhibition of spontaneous contraction of rat portal vein smooth muscle cells
- Tarantula Toxin ProTx-I Differentiates Between Human T-type Voltage-Gated Ca^ Channels Ca_v3.1 and Ca_v3.2
- Mechanisms Mediating the Vasorelaxing Action of Eugenol, a Pungent Oil, on Rabbit Arterial Tissue
- Simultaneous Activation of Ca^-Dependent K^+ and Cl^- Currents by Various Forms of Stimulation in the Membrane of Smooth Muscle Cells from the Rabbit Basilar Artery
- Fluorine-Doped Tin Dioxide Thin Films Prepared by Thermal Decomposition of Metallic Complex Salts
- Chloride Channels and Their Functional Roles in Smooth Muscle Tone in the Vasculature
- Actions of nipradilol (K-351), a new .ALPHA.- and .BETA.-adrenoceptor blocker, on the rabbit portal vein.