title: Increasing effect of ethanol on 5-HT3 receptor-mediated 14C-guanidinium influx in N1E-115 neuroblastoma cells.
abstract: N1E-115 mouse neuroblastoma cells were used to study the influence of ethanol on the 5-HT- and veratridine-induced influx of 14C-guanidinium via the 5-HT3 receptor channel and the fast sodium channel, respectively. Ethanol (10-100 mM) concentration-dependently increased the 5-HT-induced 14C-guanidinium influx, leaving the basal and veratridine (100 microM)-induced influx unaffected. The increasing effect of ethanol (100 mM) was observed at all 5-HT concentrations investigated; accordingly, ethanol increased the maximum response to 5-HT. Whereas in the absence of ethanol the concentration-response curve for 5-HT was bell-shaped, this was no longer the case when ethanol (100 mM) was present in the incubation buffer; the descending branch of the concentration-response curve for 5-HT at concentrations above 300 microM was virtually no longer observed. When, in the presence of substance P (10 microM) the 5-HT-induced 14C-guanidinium influx was already enhanced, the ability of ethanol (100 mM) to increase the 5-HT-induced influx was considerably diminished (by 72%). Preincubation of N1E-115 cells with 5-HT caused a decay of the subsequent 5-HT response ("desensitization") which was dependent on the duration of preincubation; ethanol (100 mM) did not affect the rate of this decay of the 5-HT response. The 5-HT (30 microM)-induced 14C-guanidinium influx was also increased by methanol (100 mM) and n-propanol (100 mM). The rank order of the increasing effect of the n-alkanols (at 100 mM) was: methanol < ethanol < n-propanol; i.e. the degree of enhancement increased with the lipophilicity of the alcohols.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000438:Alcohols / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D001932:Brain Neoplasms / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology*; D019791:Guanidine; D006146:Guanidines / Q000378:metabolism*; D007093:Imidazoles / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism; D013373:Substance P / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014701:Veratridine / Q000494:pharmacology
chemical_list: D000438:Alcohols; D006146:Guanidines; D007093:Imidazoles; D007211:Indoles; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; D015222:Sodium Channels; C059068:GR 65630; D012701:Serotonin; D013373:Substance P; D000431:Ethanol; D014701:Veratridine; D019791:Guanidine