| SHORT COMMUNICATION
|Year : 2000 | Volume
| Issue : 6 | Page : 365-368
Role of nitric oxide in calcium homeostasis in coronary artery of goat
DK Deka, V Raviprakash, SK Mishra
Objective : To study the role of NO in the modulation of extracellular and intracellular Ca++ in vasodilator mechanism.
Methods: Goat hearts were collected from local abattoirs within 20-30 min. of slaughter in cold aerated modified Kreb's Henseleit solution. Both the left anterior and circumflex coronary artery branches were dissected out, cut into rings of 3-4 mm length and 2-3 mm external diameter and mounted in a 20 ml organ bath through triangular stainless steel hook. The tissues were equilibrated for 90 min. under a resting tension of 1.5 g. Responses were recorded isometrically with a force displacement transducer connected to a polygraph. Role of extracellular Ca++ was studied in Ca++ - induced contractile tissues and that of intracellular Ca++ was studied in U- 46619 - contracted tissues either in the absence or presence of NO donors.
Results: SIN-1 inhibited the contractions induced by Ca++ with a rightward shift of concentration-response curve and with corresponding, but not concentration- dependent increase in EC50 . SNP caused concentration-dependent rightward shift of concentration -response curve of Ca++ . Both SIN-1 and SNP had a bimodal effect with significant inhibition at low concentration of Ca++ and a potentiating effect at high Ca++ concentration. In addition, SNP and SIN -1 inhibited U- 46619 - induced contraction dose dependently.
Conclusion: Both SIN-1 and SNP inhibited influx of extracellular Ca++ as well as release of intracellular Ca++ .
D K Deka
Source of Support: None, Conflict of Interest: None