NO synthase and guanylate cyclase inhibitors block modulation of the plasticity of common snail cholinoreceptors by 15-hydroxy-eicosatetraenoic acid.

The probable role of two second messengers, nitrogen oxide (NO) and cyclic guanosine monophosphate (cGMP) in the short- and long-latency effects of the acyclic eicosanoid 15(S)-hydroxy-5Z,8Z,11Z,13E-eicosatetraenoic acid (15-HETE) on the plasticity of somatic cholinoreceptors of identified RPa3 and LPa3 neurons of Helix lucorum, was investigated using the two-electrode voltage clamp technique on the membrane. It was demonstrated that N omega-methyl-L-arginine (an inhibitor of NO synthase), LY-83,583 [sic], and the dye methylene blue (inhibitors of soluble guanylate cyclase), when applied extracellularly, disrupt the short- and long-latency modulatory influences of 15-HETE on the depression of the inward current induced by acetylcholine during its rhythmic application to the soma. The participation of NO and cGMP in the modulatory effects of 15-HETE on the plasticity of cholinoreceptors is hypothesized.