title: Involvement of nitric oxide-dependent pathways of dorsolateral periaqueductal gray in the effects of ethanol in rats submitted to the elevated plus-maze test.
abstract: Our previous study showed the microinjection of drugs that influence the nitric oxide (NO)-mediated neurotransmission in the hippocampus impacts upon the anxiolytic-like effect of ethanol. In this study, we examined whether NO-dependent pathways of the dorsolateral periaqueductal gray (dlPAG) participate in the anxiolytic effect of ethanol in rats submitted to the elevated plus-maze test. We evaluated the impact on ethanol effects of the nitric oxide synthase (NOS) inhibitor 7-nitroindazole, the soluble guanylate cyclase inhibitor 1H-(1,2,4)-oxodiazolo (4,3-a) quinoxalin-1-one (ODQ), the cyclic guanylate monophosphate (cGMP) analogue 8-bromo-cGMP and the NO donor sodium nitroprusside. The results showed that ODQ and 7-nitroindazole increased the percentage of open arm entries and of time spent on open arms in the elevated plus maze in rats injected with ethanol at 1.0g/kg, a dose that did not produce anxiolysis per se. Conversely, 8-bromo-cGMP and sodium nitroprusside blocked the increased exploration of open arms exhibited by rats treated with a higher dose of ethanol (1.2g/kg). Taken together, the results suggest that the inhibition of NO-dependent pathways of the dlPAG enhances the anxiolytic effect of ethanol, whereas the activation of these pathways results in an opposite effect.
authors.affiliation: Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário Trindade, 88040-900 Florianópolis, SC, Brazil. gsmorato@farmaco.efsc.br
authors.forename: Gina Struffaldi
authors.initials: GS
authors.lastname: Morato
authors.forename: Roberta Moura
authors.initials: RM
authors.lastname: Ortiga
authors.forename: Vania Maria Moraes
authors.initials: VM
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D001143:Arousal / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D007274:Injections, Intraperitoneal; D008297:Male; D018782:Maze Learning / Q000187:drug effects* / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology*; D009949:Orientation / Q000187:drug effects / Q000502:physiology; D010487:Periaqueductal Gray / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
chemical_list: D009569:Nitric Oxide; D000431:Ethanol