Detail of "59946-73-5"

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Voltage-dependent effects of YC-170, a dihydropyridine calcium channel modulator, in cardiovascular tissues

Voltage-dependent effects of YC-170, a dihydropyridine calcium channel modulator, in cardiovascular tissues. Nakaya, Haruaki; Hattori, Yuichi; Tohse, Noritsugu; Kanno, Morio (Sch.Some chemicals with cas registry numbers like 59946-73-5 and 7440-70-2 are also used. Med., Hokkaido Univ., Sapporo 060, Japan). Naunyn-Schmiedeberg's Arch. Pharmacol., 333(4), 421-30 (English) 1986. CODEN: NSAPCC. ISSN: 0028-1298. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Voltage-dependent effects of YC-170 (I) [59946-73-5], a putative Ca channel activator, were examd. and compared with those Bay K 8644 [71145-03-4] in isolated guinea-pig cardiac tissues and rabbit aorta . In guinea-pig left atria superfused with a normal bathing soln. (4 mmol/L K+), both I (10 mmol/L) and Bay K 8644 (1 mmol/L) produced a pos. inotropic action accompanied by a prolongation of action potential durations (APDs). In normally-polarized guinea-pig papillary muscles Bay K 8644 increased force of contraction (fc) and APDs. However, I failed to increase fc in spite of a slight prolongation of APDs. In papillary muscles partially depolarized by 25 mmol/L K+ soln., I enhanced the elec.-induced slow action potentials and contractile force. In contrast with Bay K 8644, I significantly depressed the slow action potentials and decreased fc. I also showed the depressant action on the slow action potentials induced by isoproterenol (0.1 mmol/L), histamine (3 mmol/L), and tetraethylammonium (10 mmol/L) plus high Ca2+ (4 mmol/L). In sinoatrial node cells of guinea-pig right atria Bay K 8644 produced a pos. chronotropic action with increases in the max. rate of rise (Vmax) and action potential amplitude (APA), whereas I produced a neg. chronotropic action with decreases in Vmax and APA. In the rabbit aortic strips preincubated with bathing soln. contg. various concns. of K+ (15, 20, 30, and 40 mmol/L), Bay K 8644 produced concn.-dependent contractions in a range of concns. up to 0.3 mmol/L. However, when the concn. exceeded 1 mmol/L Bay K 8644 caused a slight relaxation, irresp. of the K+ concns. of bathing soln. I concns. of 10 and 30 mmol/L contracted the aortic strips placed in 5.9 or 15 mmol/L K+ bathing soln., but caused relaxation in 30 or 40 mmol/L K+ bathing soln. Apparently, I is a dihydropyridine Ca channel modulator which behaves as a Ca2+ channel agonist in tissues of high membrane potentials, but as a Ca2+ channel antagonist in tissues of low membrane potentials. .