S254 P.1.d Basic neuroscience – Animal behaviour ever, the precise role attributed to the preferential kappa opioid endogenous ligand dynorphin remains to be clarified. The purpose of this study was to examine the acute (time course related actions) and chronic effects of ethanol (voluntary or forced intake) on prodynorphin gene expression in selected areas of the rat brain involved in stress and dependence. The analysis of conditioned place preference for ethanol in prodynorphin knock out and wild type mice was also evaluated. To this aim, four experiments were carried. In situ hybridisation histochemistry was used to examine in coronal brain sections of rats the prodynorphin mRNA alterations induced by different patterns of ethanol intake. In experiment 1, the intragastric administration (3 g/kg of ethanol, p.o., 3 ml/kg; 1, 2, 4, 8 and 24 h) produced time- related and pronounced increases (20−30%, between 2−4 h) in prodynorphin gene expression in caudate-putamen (CPu), nucleus accumbens core AcbC, nucleus accumbens shell (AcbS), hy- pothalamic paraventricular nucleus (PVN) and supraoptic nucleus (SON). In experiment 2, the effects of forced intake of ethanol (26 days of phase of induction increasing the concentration of ethanol from 0 to 10% every 4 days followed by 26 days of maintenance at 10% ethanol concentration; average intake 4−5 g/kg/day) produced marked decreases in CPu (54%), AcbC (63%) and AcbS (48%) whereas increased prodynorphin gene expression in PVN (48%) and SON (15%). In experiment 3, the effects of voluntary ethanol intake between Wistar rats made preferring to ethanol were compared to non- preferring rats following the same induction and maintenance phases previously described in experiment 2. Rats were divided into three groups: (1) water drinking rats (W); (2) ethanol prefer- ring group (P; intake > 3.5 g ethanol/kg/day) and (3) ethanol non- preferring group (NP; intake < 1.5 g ethanol/kg/day). The results revealed a pronounced decrease in prodynorphin gene expression in CPu (30%) and AcbC (37%) in the P group that is significantly different from the W and NP groups. These results strongly sug- gest that development of excessive voluntary ethanol consumption is related to decreased expression of prodynorphin gene in brain areas related to reward. To further examine this assumption, in experiment 4 condi- tioned place preference of ethanol (2 g/kg, p.o) was examined in prodynorphin knock out and their corresponding wild type mice. Mice underwent an unbiased conditioning procedure for ethanol-induced place preference. This test revealed that deletion of prodynorphin gene increased (49%) the time spent in the place conditioned of ethanol compared to wild type mice. Taken together, these results point to the endogenous kappa opi- oid ligand dynorphin as an essential component of the molecular pathways underlying the development of ethanol dependence and therefore drugs targeting this opioid peptide may be beneficial to treat problems related to excessive ethanol consumption. Supported by Grant from Spanish Ministry of Health (FIS PI050429) to J. Manzanares. P.1.d.009 Possible involvement of GABAA-benzo- diazepine receptor in the anxiolytic-like effect induced by Passiflora actinia extracts in mice R.M.W. Oliveira 1 ° , L.F. Lolli 1 , C.A. Santos 2 . 1 UEM, Department of Pharmacology, Maring´ a, Brazil; 2 UFPR, Department of Pharmacy, Maring´ a, Brazil Purpose of the Study: Aerial parts of Passiflora specie have been traditionally used to treat anxiety, insomnia and nervousness. Passiflora actinia Hooker is a native species widely distributed through Southern Brazil. High-performance liquid chromatog- raphy (HPLC) comparative analysis of the active fractions of Passiflora actinia has suggested a closer chromatographic profile with Passiflora incarnata. Isovitexin was present in methanol and aqueous fractions obtained of Passiflora actinia, while standard alkaloids such as harman, harmin, harmaline or harmalol were not detected. Intraperitoneal (i.p.) injections of Passiflora actinia crude extract cause sedative effects in mice, observed as a pronounced decrease in the number of entries in enclosed and open arms of the elevated plus maze (EPM) and a decrease in the in the general motor activity in the open field. The aim of the present study was to evaluate the behavioral effects of oral administration of Passiflora actinia hydroethanol (HE) and methanol (ME) extracts in mice using the EPM model of anxiety. Methods: Male albino-Swiss mice received a single or repeated (twice a day for 6 days) administration of HE or ME extracts and 30 min later were submitted to the EPM. In another set of ex- periment, mice were treated with saline or flumazenil (10 mg/Kg, i.p.) 30 min before the oral administration of HE (600 mg/Kg, p.o.) or ME extracts (300 mg/Kg). Flumazenil, a specific GABAA antagonist, was used to determine the role of GABA-system in the probable action of the extracts. The number of open and enclosed arm entries and time spent in both arms of the EPM were recorded for 5 min. Results: A single administration of HE (300 and 600 mg/Kg) or ME (100 and 300 mg/Kg) resulted in a significant in- crease in the% of the number (HE F3.39 = 7.93, p < 0.001; ME F3.39 = 11.04, p < 0.001) and the time (HE F3.39 = 7.28, p < 0.001; ME F3.39 = 13.04, p < 0.001) into the open arms of the EPM (Figure 1). These treatments did not result in any significant changes in motor activity as can be observed by the number in the enclosed arms (p>0.05). Although flumazenil caused no significant change in the EPM open arms (p>0.05 for entries or time), it completely inhibited the anxiolytic–like effect of diazepam, HE and ME as seen by the % of open arm entries (diazepam F3.39 = 16.58, p < 0.001; HE F3.39 = 22.2, p < 0.001; ME, F3.39 = 10.42, p < 0.05) as well as of the % of time (diazepam F3.39 = 21.33, p < 0.001; HE F3.39 = 43.57, p < 0.001; ME, F3.39 = 17.04, p < 0.001) spent in the EPM. Repeated ad- ministration of HE (100 and 300 mg/kg) produced an enhanced open arm exploration as seen by an increase in the % of entries (F2.29 = 4.86, p < 0.05) as well as % of time (F2.29 = 10.2, p < 0.001) in the open arms of the maze. However, no anxiolytic activity was detected after repeated treatment with ME tested doses (p>0.01), indicating a development of pharmacological tolerance. Conclusions: The present study provides evidence that HE and ME obtained from Passiflora actinia possesses anxiolytic- like effects when administered orally to mice. The anxiolytic activity might be mediated, at least partly, through benzodiazepine receptors. P.1.d.010 A dopaminergic mechanism recruited in the anti-punitive effect of the DOI in the four-plates test-retest paradigm N. Ripoll, M. Hascoet, M. Bourin ° . Faculty of Medicine, Pharmacology, Nantes, France Purpose of the Study: Retesting mice in the four-plates test (FPT) model of anxiety, 24 h after a first test, leads to an