Effects of calcium channel agonists (BAY K 8644, CGP28392 and YC-170) on 45Ca uptake by rat uterine segments.
The characteristics of the stimulating effects of the calcium channel agonists BAY K 8644, CGP28392 and YC-170 on 45Ca uptake by rat uterine segments were investigated. BAY K 8644, CGP28392 and YC-170 caused about 150, 100 and 150% increase, respectively in the 45Ca uptake induced by 20 mM KCl. The ED50 values of BAY K 8644, CGP28392 and YC-170 were 1.8 X 10(-9), 2.5 X 10(-8) and 9.8 X 10(-9) M, respectively. These agonists had little effect on the 45Ca uptake induced by 10(-6) M acetylcholine. They also did not affect the basal 45Ca uptake. Their enhancing effects were blocked by the Ca channel antagonist nitrendipine. We conclude that rat uterine segments have voltage-sensitive Ca channels that are stimulated by Ca channel agonists (BAY K 8644, CGP28392 and YC-170) under depolarizing conditions and that the characteristics of the stimulating effects of CGP28392 and YC-170 on 45Ca uptake by rat uterine segments are qualitatively the same as those of BAY K 8644.
Ichida
S
S
Department of Biological Chemistry, Faculty of Pharmacy, Kinki University, Osaka, Japan.
Ariyoshi
S
S
Fujisue
T
T
Wada
T
T
Akimoto
T
T
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects; D005260:Female; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009568:Nitrendipine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism
D002120:Calcium Channel Agonists; D015220:Calcium Channels; D011725:Pyridines; C046721:YC 170; D011189:Potassium Chloride; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; C040525:CGP 28392; D009568:Nitrendipine; D009543:Nifedipine; D002118:Calcium