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1. Carbachol produced a relaxation of dilator muscle at a concentration lower than 1 microM and a contraction at a concentration higher than 1 microM. 2. We studied the effects of the M1-selective antagonist, pirenzepine, the M2-selective antagonist, himbacine, the M3-selective antagonist, 4-diphenyl-acetoxy-N-methylpiperidine methiodide (4-DAMP) and the(More)
1. We determined the endothelin (ET) receptor subtype involved in the facilitation of electrical field stimulation-(EFS) induced contraction using the ETB receptor agonist sarafotoxin S6c (STX S6c) and the ET receptor antagonists TTA-386 and bosentan. 2. ET-3-and ETB-receptor-selective agonist STX S6c enhanced EFS-induced contractions. The increasing effect(More)
This study was done to determine the alpha1-adrenoceptor subtypes and to characterize the functional role of alpha1D-adrenoceptors in the following rabbit arteries: thoracic and abdominal aorta, mesenteric, renal and iliac arteries. In all arteries, selective alpha1D-adrenoceptor antagonist BMY 7378(More)
Fullerene (C(60)), a condensed ring aromatic compound with extended pi systems, is a novel carbon allotrope. Because of its poor solubility in polar solvents, investigation of the biological and pharmacological properties of fullerene has been difficult. Recently, water-soluble fullerene derivatives have been synthesized, and we and others have found that(More)
Contractile mechanisms by carbachol and ATP were compared in the detrusor strips of rabbit bladder. To exclude modulation of the agonists-induced responses by intramurally synthesized prostaglandins, all the experiments were done in the presence of the potent cyclooxygenase inhibitor flurbiprofen (1 microM). The concentration-response curves for carbachol(More)
We investigated the mechanism of vascular relaxation by denopamine (Deno), an oral positive inotropic agent that has selective beta 1-adrenergic action. Deno relaxed, dose-dependently (0.1-30 microM), ring segments of rabbit aorta, which were partially precontracted with 1 microM phenylephrine (Phe) or norepinephrine (NE), but did not relax those(More)
Optical isomers of YM-12617, a potent and selective alpha 1-adrenoceptor blocker, were tested on the rabbit iris dilator and aorta. The order of potency was R(-)-isomer greater than racemate greater than S(+)-isomer. The R(-)-isomer and racemate behaved as an essentially irreversible antagonist to norepinephrine in the iris dilator where the efficacy of(More)
We have characterized muscarinic cholinergic receptor sites and interaction of various modulators of intracellular Ca mobilization, such as 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8), ryanodine, procaine and related drugs with the receptor sites, using a binding assay method with [3H]quinuclidinyl benzilate [( 3H]QNB) in guinea(More)
The effects of age on alpha1-adrenoceptor and Ca2+ channel-mediated contractile mechanisms in the thoracic aorta, isolated from rats of 3, 6, 10, 18 and 40 weeks old, were studied. The potency (pD(2) value) of norepinephrine increased with age from 3 to 10 weeks, but decreased thereafter from 10 to 40 weeks. The change in pD(2) value of norepinephrine was(More)