Involvement of nitric oxide-dependent pathways of dorsolateral periaqueductal gray in the effects of ethanol in rats submitted to the elevated plus-maze test.
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.
Morato
Gina Struffaldi
GS
Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário Trindade, 88040-900 Florianópolis, SC, Brazil. gsmorato@farmaco.efsc.br
Ortiga
Roberta Moura
RM
Ferreira
Vania Maria Moraes
VM
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
D009569:Nitric Oxide; D000431:Ethanol