P-2 PURINOCEPTOR-MEDIATED INTRACELLULAR CA2+ TRANSIENTS IN HUMAN SURAL NERVE

SEGMENTS of biopsied human sural nerve were stained with the Ca2+-sens itive fluorescent dyes Calcium Green-1 and Fura Red. The emission rati o was used to follow changes in the intracellular free Ca2+ concentrat ion ([Ca2+](i)). Application of ATP and analogues in concentrations be tween 0.3 and 300 mu M via the bathing solution resulted in a transien t rise in [Ca2+](i). The rank order of agonist potency, 2-methylthioAT P>ATP>UTP, and the failure of adenosine, alpha,beta-MeATP and beta,gam ma-MeATP to evoke rises in [Ca2+](i) indicate the presence of P-2Y/U s ubtypes of purinoceptors in this preparation. ATP-induced Ca2+ transie nts in biopsied human nerve preparations might serve as a diagnostic t ool in neuropathies.