Potent alpha-adrenoceptor blocking action of SGB-1534, a new quinazoline antihypertensive agent in vitro experiments.
SGB-1534 inhibited the contractile response to norepinephrine (NE), methoxamine (MO) and electrical transmural stimulation in the rabbit aorta, basilar and cat coronary arteries and only in the rabbit aorta its inhibitor action was a competitive manner. In the rabbit aorta, the potency (pA2) of SGB was greater than that of prazosin, whereas in the other preparations, the effect of SGB was comparable to that of prazosin. In the rabbit aorta, both SGB and prazosin abolished the contraction induced by transmural stimulation. In the guinea-pig vas deferens, SGB failed to affect the inhibitory effect of clonidine on the response to electrical field stimulation. SGB had no inhibitory effects on the contractile response to potassium, 5-hydroxytryptamine, PGF2 alpha and an excess Ca2+ and the relaxing response to isoproterenol in the vascular tissues. In the electrically driven left atria of guinea-pigs, SGB had no effect on the electromechanical parameters and the isoproterenol induced inotropic effect. On the specific binding of [3H]prazosin in the rabbit aorta, the inhibitory effect of SGB was greater than that of prazosin and phentolamine.
Shibata
S
S
Satake
N
N
Suh
T K
TK
Ishida
Y
Y
Ueda
S
S
Follmer
C
C
Flores
F
F
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000378:metabolism / Q000494:pharmacology*; D001013:Aorta, Thoracic / Q000187:drug effects; D001488:Basilar Artery / Q000187:drug effects; D002415:Cats; D003331:Coronary Vessels / Q000187:drug effects; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects; D011224:Prazosin / Q000494:pharmacology; D011799:Quinazolines / Q000378:metabolism / Q000494:pharmacology*; D011817:Rabbits; D014649:Vas Deferens / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D000959:Antihypertensive Agents; D011799:Quinazolines; C042712:SGB 1534; D011224:Prazosin