Effect of nifedipine and dipyridamole on K+ and NA stimulated 45Ca-uptake into rabbit aortic strips.
The effect of dipyridamole (DPM), a purine nucleoside uptake inhibitor, on the K+ and noradrenaline (NA)-stimulated 45Ca-uptake into Rabbit aortic strips was studied and compared with that of nifedipine (NFD). DPM (10(-6) M) significantly (P < 0.02) inhibited 45Ca-uptake in aortic strips stimulated with K+ (10(-1) M). However, it had less significant effect on NA (10(-4) M)-stimulated 45Ca-uptake. The percentage inhibition was 80 and 57 in K+ and NA-stimulated 45Ca-uptake, respectively. Similarly, NFD (10(-7) M) caused significant (P < 0.01, P < 0.05) decrease in K+ (0.060 +/- 0.009) and NA (0.082 + 0.01, mM)-stimulated 45Ca-uptake. The percentage inhibition by NFD was 98 and 64 in K+ and NA-stimulated 45Ca-uptake, respectively. The results suggest that DPM inhibits Ca2+ influx occurring through Voltage Operated Calcium Channels (VOCCs) but it has little effect on Receptor Operated Calcium Channels (ROCCs).
Parija
S C
SC
Division of Pharmacology and Toxicology, Indian Veterinary Research Institute, Izatnagar.
Raviprakash
V
V
Mishra
S K
SK
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects*; D004176:Dipyridamole / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011817:Rabbits
D015220:Calcium Channels; D004176:Dipyridamole; D009543:Nifedipine; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine