INFLUENCE OF LEUKOTRIENE-B-4, LEUKOTRIENE -C-4, 12-HYDROXYEICOSATETRAENOIC ACID, TREO-EPIMERES AND ERITRO-EPIMERES OF HEPOXILIN-B-3 ON CHOLINORECEPTOR PLASTICITY OF HELIX NEURONS

Effects of several acyclic eicosanoids (which are formed from arachido nic acid under the action of 5- and 12-lipoxygenases) on desensitizati on of somatic cholinoreceptors of Helix lucorum RPa3 and LPa3 neurons were studied by means of two-electrode voltage clamp technique. The su bstances under study were: leukotrienes B-4, C-4,12(S)-hydroxy-(5Z,8Z, 10E,14Z)-eicosatetraenoic acid (12-HETE), treo- and eritro-epimeres o f hepoxilin B-3. Cholinoreceptor plasticity was evaluated by a degree of depression of inward current, induced by rhythmical local ACh appli cations on the soma with intervals 55-180 sec. Leukotrienes B-4 and C- 4 intensified cholinoreceptor plasticity. Inhibitor Of inositol- 1,4,5 -trisphosphate-dependent (IP3-d) mobilization of depoted Ca2+, TMB-8, prevented the effect of leukotriene C-4. 12-HETE, treo- and eritro-epi meres df hepoxilin B-3 did not change plasticity. A conclusion is made that cholinoreceptor plasticity is controlled by leukotrienes B-4 and C-4. One of the regulatory pathways includes IP3-dlipoxygenase pathwa y (12-HETE, treo- and eritro-epimeres of hepoxilin B-3) do not partici pate in this intracellular regulatory mechanism.