PURIFICATION OF A 5-HT UPTAKE INHIBITOR FROM THE VENOM OF CERASTES VIPERA

A protein that inhibits the re-uptake of 5-hydroxytryptamine into rat brain synaptosomes was isolated from the venom of the Sahara sand vipe r (Cerastes vipera) by gel filtration and reverse phase chromatography . It has a molecular weight of 13739 Da and an IC50 of about 50 nM for blocking uptake of H-3-5-HT into rat brain synaptosomes. It also augm ented the responses to 5-HT in a smooth muscle preparation. It has pho spholipase A(2) activity, but it has no lytic activity as measured by its inability to release lactate dehydrogenase from rat brain synaptos omes. Determination of the N-terminal sequence revealed a similarity w ith a phospholipase A(2) previously isolated from Cerastes cerastes ve nom. (C) 1998 Elsevier Science Ltd. All rights reserved.