Effect of Leiurus quinquestriatus hebreus venom on calcium and deoxyglucose uptake in cultured cardiac cells.
The effects of scorpion venom Leiurus quinquestriatus hebreus were studied on cardiac cells grown in culture. The venom (30 micrograms/ml) increased significantly (P < 0.05) Ca2+ uptake into intact cardiocytes and to sarcoplasmic reticulum of skinned cells. [3H]Deoxyglucose uptake was also increased significantly (P < 0.05) in venom treated cardiocytes. It was found that fractions I and III of the venom, separated by gel filtration and ion exchange chromatography, are responsible for the increased Ca2+ uptake by the sarcoplasmic reticulum, whereas fraction IIb, III and IV are responsible for the accelerated rate of uptake of 45Ca and [3H]deoxyglucose by intact cells. Ca channel blockers prevented these effects and similar results were obtained by propranolol. Thus, it is concluded that the venom exerts its effect through activation of beta-adrenoceptors which causes the opening of L-type Ca channels.
Arie-Saadia
G
G
Otto Meyerhoff Drug Receptor Center, Department of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.
Sofer
S
S
Zlotkin
E
E
Shainberg
A
A
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D002478:Cells, Cultured; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003847:Deoxyglucose / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D012604:Scorpion Venoms / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D012604:Scorpion Venoms; D003847:Deoxyglucose; D011433:Propranolol; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium