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Pubertal stress and neonatal immune activation with lipopolysaccharide promotes anxious- and negative-like schizophrenia symptom in adulthood rats: effect of gender
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P.1.h. Basic and clinical neuroscience − Animal behaviour
compare and examine the underlying mechanism of action of these drugs. Methods: C57BL/6J mice were injected twice a day for 3 weeks with morphine (MOR, increasing doses, 20–100 mg/kg i.p.), once a day with dexamethasone (DEX, 4 mg/kg i.p.) or saline (SAL, 10 ml/kg i.p.). All groups of animals were left for additional 3 weeks to spontaneously withdraw without injection. To evaluate the depressive-like behaviors, three tests were conducted: social interaction, light/dark box and tail suspension. We used realtime PCR to map transcription in the hippocampus of mouse brain undergoing MOR and DEX treatment and followed by the 21 days of abstinence. The results were analyzed by factorial ANOVA, using two categorical factors: “treatment” (SAL, MOR and DEX) and “experimental phase” (acute, chronic, chronic with acute induction, withdrawal and withdrawal with acute induction) followed by Bonferroni’s post hoc tests. Results: MOR- as well as DEX-abstinent animals exhibited an increased immobility time in tail suspension test, which is significant depression symptom in mice (F2,43 = 5.13, p < 0.01). Depression-like behaviors we also noticed in chronic treatment paradigm in DEX-treated but not MOR-treated mice. Our analysis found that mRNA expression of GR (Nr3c1) was decreased in hippocampus of MOR- and DEX-treated (t = 4.12, p < 0.001) as well as MOR- and DEX-withdrawn mice (t = 2.82, p < 0.05). Opposite pattern of increased expression was found for stressinducible genes (Fkbp5, Tsc22d3) after acute administration of MOR (t = 6.38, p < 0.0001) and DEX (t = 15.44, p < 0.0001). In contrast, ANOVA tests indicated significant differences between MOR and DEX-treated in immediate-early genes expression (c-Fos, Arc, Npas4 and Bdnf). Previous analysis revealed that MOR affect expression of CAMK family genes. We noticed that MOR and DEX treatment significantly modified levels of mRNA Camk1g (t = 5.26, p < 0.0001), one of the characteristic gene of the structure of hippocampus. Conclusions: Acute administration of MOR and DEX initially affect glucocorticoid pathway in the hippocampus in a similar manner. In difference, the prolonged drugs administration and abstinence regulate the molecular pathways differentially. Thus, differential molecular mechanism appears to be involved in depression evoked by opioid withdrawal and chronic glucocorticoids in hippocampus. References [1] Gray, J.D, Rubin, T.G, Hunter, R.G., McEwen, B.S., 2014. Hippocampal gene expression changes underlying stress sensitization and recovery. Molecular Psychiatry 19, 1171–1178. [2] Law, J., Ibarguen-Vargas, Y., Belzungc, C., Surgeta, A., 2016. Decline of hippocampal stress reactivity and neuronal ensemblecoherence in a mouse model of depression. Psychoneuroendocrinology 67, 113–123. [3] Skupio, U., Tertil, M., Sikora, M., Golda, S., Wawrzczak-Bargiela, A., Przewlocki, R., 2015. Behavioral and molecular alterations in mice resulting from chronic treatment with dexamethasone: Relevance to depression. Neuroscience 286, 141–150. [4] Ammon-Treiber, S., Hollt. V., 2005. Morphine-induced Changes of Gene Expression in the Brain. Addiction Biology 10, 81−89. Disclosure statement: Funding for this study was provided by Polish National Science Centre Grant: 2013/08/A/NZ3/00848.
P.1.h.047 Pubertal stress and neonatal immune activation with lipopolysaccharide promotes anxious- and negative-like schizophrenia symptom in adulthood rats: effect of gender C.S. Custodio1 ° , T.M.M. Viana1 , A.J.M. Chaves Filho2 , B.S.F. Mello1 , V. Borella3 , L. Fernandes2 , D. Macedo3 1 Federal University of Cear´a, Program in Medical MicrobiologyDepartment of Pathology- Faculty of Medicine, Fortaleza, Brazil; 2 Federal University of Cear´ a, Faculty of Medicine, Fortaleza, Brazil; 3 Federal University of Cear´a, Department of Physiology and Pharmacology- Faculty of Medicine, Fortaleza, Brazil Background: In mammalians, there are two major periods of intense synaptic production and pruning: before and immediately after birth (pre- and neonatal period) and during the transition from childhood to adolescence (peripubertal period) [1]. Negative life events in these periods can impact the immune system and neuroendocrine responses and alter the normal trajectory of brain development towards psychopathology. In rodents, these events have been modeled by different factors, such as parenteral deprivation, environmental stress and immunostimulant agents [2]. Aim: To investigate the behavioral alterations in adult male and female rats submitted to neonatal administration of lipopolysaccharide (LPS) and/orperipubertal stress. Methods: In the neonatal period, postnatal days (PN) 5th and 7th, Wistar rats were injected with LPS (50mg / kg, i.p.) or saline (SAL). Between the PN35-PN43 (peripubertal period), the animals were submitted to stress (+ stress) or not (− stress) [3]. At PN60, the behavioral analysis was performed (open field, forced swimming test and sucrose consumption tests). The data were analyzed by two-way ANOVA with Tukey as post hoc test considering statistical significance when P < 0.05. Results: In the open field test, the group LPS + stress showed an increase in the number of rearings compared to the groups SAL − stress (p < 0.01) and SAL + stress (p < 0.001). Also in the males, the group LPS + stress presented a reduction in the number of groomings compared to the group SAL − stress (p < 0.05). Regarding the time spent in the arena central area, females submitted to LPS + stress presented a reduction in this parameter compared to the groups SAL − stress (p < 0.001) and LPS − stress (p < 0.001). In the forced swimming test, the group of male LPS + stress presented an increase in the immobility time compared to the groups SAL − stress (p < 0.0001) and LPS − stress (p < 0.05). In females, the groups LPS − stress (p < 0.0001), SAL + stress (p < 0.01) and LPS + stress (p < 0.01) presented an increase in immobility time compared to the group SAL − stress. No significant alteration was observed in the sucrose consumption between the groups delineated in this study. Conclusions: Our results demonstrated that the animals submitted to neonatal LPS and peripubertal stress presented important behavioral alterations in adulthood, especially anxiouslike and negative-likeschizophrenia symptom. This conclusion is reinforced by the findings of increased immobility in the forced swimming test not accompanied by decreases in sucrose preference. Furthermore, LPS +stress group presented decreased number of grooming behavior. This calls attention for a possible loosing interest in everyday activities. The gender seems to influence the vulnerability to these events, since females were more vulnerable to the peripubertal stress than neonatal LPS to the development of anxious-like behavior, whilethe males showed
P.1.h. Basic and clinical neuroscience − Animal behaviour a possible synergistic effect between these two events to the development of negative-like symptoms. References [1] Andersen, S.L., 2003. Trajectories of brain development: Point of vulnerability or window of opportunity? Neurosci. Biobehav. Rev. 27, 3−18. [2] Ganguly, P., Brenhouse, H.C., 2014. Broken or maladaptive? Altered trajectories in neuroinflammation and behavior after early life adversity. Dev. Cogn. Neurosci. 11, 18−30. [3] Giovanoli, S., Engler, H., Engler, a., Richetto, J., Voget, M., Willi, R., Winter, C., Riva, M. a., Mortensen, P.B., Feldon, J., Schedlowski, M., Meyer, U., 2013. Stress in Puberty Unmasks Latent Neuropathological Consequences of Prenatal Immune Activation in Mice. Science (80). 339, 1095–1099. doi:10.1126/science.1228261.
P.1.h.048 The effect of one month riboflavin administration on thermo-nociceptive behavior and locomotion in mice C. Bohotin1,2 , T. Alexa2 , A. Luca1,2 ° , A. Dondas2 , D. Nebunu2 , R. Iliescu2,3 1 “Gr. T. Popa” University of Medicine and Pharmacy, Pathophysiology, Iasi, Romania; 2 “Gr. T. Popa” University of Medicine and Pharmacy, Centre for the Study and Therapy of Pain, Iasi, Romania; 3 “Gr. T. Popa” University of Medicine and Pharmacy, Pharmacology, Iasi, Romania Purpose: Certain neurotransmitters, including serotonin, norepinephrine or dopamine are metabolized by the monoamine oxidase (MAO), a mitochondrial outer membrane enzyme, dependent on FAD, the coenzyme form of riboflavin [1,2]. Riboflavin administration restores and stimulates MAO activity [3]. All MAOdependent neurotransmitters are involved in depression, pain and locomotion control. We therefore decided to explore the effect of repeated riboflavin administration (four weeks) on thermonociception, motor coordination and locomotor activity. Methods: 20 male BALB/c mice, weight 33±2 g, were divided in 2 groups: the riboflavin group (n = 12), and the control group (n = 8). The mice received daily riboflavin (50 mg/kg b.w.) or saline (the same volume as riboflavin treated mice) intraperitoneal injections and were evaluated for thermo-nociception, motor coordination and locomotor activity before treatment (baseline) and every two days thereafter, for a 28-day period. Nociception was evaluated using tail flick latency test (TFLT) and hot plate test (HPT). Motor coordination has been assessed by the rotarod test (RT). The Ugo Basile Activity Cage was used to measure horizontal (HLA) and vertical (VLA) locomotor activity. The cut off was set at 12s for TFLT, 15s for HPT and 300s for RT. The locomotor activity was evaluated for 3 minutes. The data for days 7, 14, 21, and 28 are presented in seconds and in percentage changes from baseline [PBC = (treated − baseline)×100/baseline]. Statistical significance was assessed by paired t-tests or ANOVA as appropriate. Results: Riboflavin had no statistically significant effect on thermo-nociception neither when compared with baseline nor with control group. However, the PBC for HPT in the saline group varied from −2% to +10%, while in the riboflavin group from −23% to 5%, whereas for TFLT, variations were 3−7.5% and −2−10%, respectively. We noticed a tendency towards hyperalgesia in the last week of treatment on the HPT. No changes on motor coordination were observed during riboflavin/saline treatment. By contrary, a significant decrease in rearing (day 28, −43.97±54.4%, p = 0.03) and horizontal movements (day 28,
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36.1±13%, p = 0.02) were noticed in the riboflavin-treated mice when compared with baseline or with control group. Starting from the first week, the decrease was significant for both vertical and horizontal movements. Briefly, our results show that one month of riboflavin treatment has no significant effects on nociception, no effect on motor coordination and has a powerful effect on mice’s exploratory behavior − the animals preferred to stay into the unprotected center area of the activity cage thus indicating that riboflavin has an anxiolytic-like behavior [3]. Conclusion: Even though riboflavin controls MAO metabolism through a mitochondrial FAD-dependent enzymes, it seems that it has different effects on MAO-dependent neurotransmitters, being more important for those involved in anxiety than those involved in pain and locomotion control. References [1] Zhou, B.P., Duane, A.L., Kwan S.W., 1995. Flavinylation of Monoamine Oxidase B J. Biol. Chem. 270: 23653–23660. [2] Edmondson, DE, Binda, C, Mattevi, A. 2004. The FAD binding sites of human monoamine oxidases A and B. Neurotoxicology 25, 63−72. [3] Bonnefil, V., Castiglione, CM, Cawthon, RM, Breakefield, XO 1981. Effect of riboflavin on monoamine oxidase activity in cultured neuroblastoma cells. Cell Mol Neurobiol 1, 351−9. [4] Bailey, K.R., Crawley, J.N., 2009. Anxiety-Related Behaviors in Mice. In:Buccafusco JJ, editor. Methods of Behavior Analysis in Neuroscience. 2nd edition. Boca Raton (FL):CRC Press/Taylor & Francis.
P.1.h.049 Electrical stimulation of the raphe magnus evoked changes in rats behaviour K. Ptaszek1 ° , E. Kurowska1 , M. Podlacha1 , J. Rucinski1 , E. Jurkowlaniec1 1 University of Gdansk Biology, Department of Animal and Human Physiology, Gdansk, Poland Serotonin (5-HT) regulates many fundamental aspects of physiology and behaviour including gastrointestinal functions and mood [1]. Peripheral 5-HT is synthesized and stored in the enterochromaffin cells found in the gastrointestinal tract crypts as well as in the platelets. In the central nervous system, fibers which are immunoreactive to 5-HT are widely distributed. However, the cells which produce 5-HT are found only in the restricted areas of the brain, namely in raphe nuclei groups which extend from the midbrain to the medulla. The raphe magnus (RMg) located in the B3 region has projection pathways mainly to the spinal cord [2]. The purpose of this study was to analyse the influence of electrical stimulation of the RMg on rats behaviour in three different modalities: learning, sociability and anxiety. The experiment was performed on a group of ten 3-month old male Wistar rats (weight ±250 g). Rats were implanted with electrodes into the RMg under isoflurane (1−2.5% in oxygen; Aerrane) anesthesia and butorphanol analgesia (1.5 mg/300 g b.w.; Butomidor). After 10-day convalescence, 16-day electrical stimulation was carried out at the intensity of stimulation current (60– 160 mA) determined individually for each rat. Rats were divided into stimulated (n = 7) and non-stimulated (sham, n = 3) groups. Every day, 25 stimulation trials were carried out, consisting of 30-second stimulation followed by 20-second interval. In the sham group, no current was passed through the electrode. During stimulations, the locomotor activity was measured by an actometer (Opto Varimex Minor). Furthermore, the rats’ memory (in the Morris Water Maze test; WM), anxiety level (in the Elevated Plus Maze test; EPM) and social responses (in the 3 chamber test; 3C) were analysed 30 minutes after stimulation trials on the 5th, 9th
P.1.h. Basic and clinical neuroscience − Animal behaviour
compare and examine the underlying mechanism of action of these drugs. Methods: C57BL/6J mice were injected twice a day for 3 weeks with morphine (MOR, increasing doses, 20–100 mg/kg i.p.), once a day with dexamethasone (DEX, 4 mg/kg i.p.) or saline (SAL, 10 ml/kg i.p.). All groups of animals were left for additional 3 weeks to spontaneously withdraw without injection. To evaluate the depressive-like behaviors, three tests were conducted: social interaction, light/dark box and tail suspension. We used realtime PCR to map transcription in the hippocampus of mouse brain undergoing MOR and DEX treatment and followed by the 21 days of abstinence. The results were analyzed by factorial ANOVA, using two categorical factors: “treatment” (SAL, MOR and DEX) and “experimental phase” (acute, chronic, chronic with acute induction, withdrawal and withdrawal with acute induction) followed by Bonferroni’s post hoc tests. Results: MOR- as well as DEX-abstinent animals exhibited an increased immobility time in tail suspension test, which is significant depression symptom in mice (F2,43 = 5.13, p < 0.01). Depression-like behaviors we also noticed in chronic treatment paradigm in DEX-treated but not MOR-treated mice. Our analysis found that mRNA expression of GR (Nr3c1) was decreased in hippocampus of MOR- and DEX-treated (t = 4.12, p < 0.001) as well as MOR- and DEX-withdrawn mice (t = 2.82, p < 0.05). Opposite pattern of increased expression was found for stressinducible genes (Fkbp5, Tsc22d3) after acute administration of MOR (t = 6.38, p < 0.0001) and DEX (t = 15.44, p < 0.0001). In contrast, ANOVA tests indicated significant differences between MOR and DEX-treated in immediate-early genes expression (c-Fos, Arc, Npas4 and Bdnf). Previous analysis revealed that MOR affect expression of CAMK family genes. We noticed that MOR and DEX treatment significantly modified levels of mRNA Camk1g (t = 5.26, p < 0.0001), one of the characteristic gene of the structure of hippocampus. Conclusions: Acute administration of MOR and DEX initially affect glucocorticoid pathway in the hippocampus in a similar manner. In difference, the prolonged drugs administration and abstinence regulate the molecular pathways differentially. Thus, differential molecular mechanism appears to be involved in depression evoked by opioid withdrawal and chronic glucocorticoids in hippocampus. References [1] Gray, J.D, Rubin, T.G, Hunter, R.G., McEwen, B.S., 2014. Hippocampal gene expression changes underlying stress sensitization and recovery. Molecular Psychiatry 19, 1171–1178. [2] Law, J., Ibarguen-Vargas, Y., Belzungc, C., Surgeta, A., 2016. Decline of hippocampal stress reactivity and neuronal ensemblecoherence in a mouse model of depression. Psychoneuroendocrinology 67, 113–123. [3] Skupio, U., Tertil, M., Sikora, M., Golda, S., Wawrzczak-Bargiela, A., Przewlocki, R., 2015. Behavioral and molecular alterations in mice resulting from chronic treatment with dexamethasone: Relevance to depression. Neuroscience 286, 141–150. [4] Ammon-Treiber, S., Hollt. V., 2005. Morphine-induced Changes of Gene Expression in the Brain. Addiction Biology 10, 81−89. Disclosure statement: Funding for this study was provided by Polish National Science Centre Grant: 2013/08/A/NZ3/00848.
P.1.h.047 Pubertal stress and neonatal immune activation with lipopolysaccharide promotes anxious- and negative-like schizophrenia symptom in adulthood rats: effect of gender C.S. Custodio1 ° , T.M.M. Viana1 , A.J.M. Chaves Filho2 , B.S.F. Mello1 , V. Borella3 , L. Fernandes2 , D. Macedo3 1 Federal University of Cear´a, Program in Medical MicrobiologyDepartment of Pathology- Faculty of Medicine, Fortaleza, Brazil; 2 Federal University of Cear´ a, Faculty of Medicine, Fortaleza, Brazil; 3 Federal University of Cear´a, Department of Physiology and Pharmacology- Faculty of Medicine, Fortaleza, Brazil Background: In mammalians, there are two major periods of intense synaptic production and pruning: before and immediately after birth (pre- and neonatal period) and during the transition from childhood to adolescence (peripubertal period) [1]. Negative life events in these periods can impact the immune system and neuroendocrine responses and alter the normal trajectory of brain development towards psychopathology. In rodents, these events have been modeled by different factors, such as parenteral deprivation, environmental stress and immunostimulant agents [2]. Aim: To investigate the behavioral alterations in adult male and female rats submitted to neonatal administration of lipopolysaccharide (LPS) and/orperipubertal stress. Methods: In the neonatal period, postnatal days (PN) 5th and 7th, Wistar rats were injected with LPS (50mg / kg, i.p.) or saline (SAL). Between the PN35-PN43 (peripubertal period), the animals were submitted to stress (+ stress) or not (− stress) [3]. At PN60, the behavioral analysis was performed (open field, forced swimming test and sucrose consumption tests). The data were analyzed by two-way ANOVA with Tukey as post hoc test considering statistical significance when P < 0.05. Results: In the open field test, the group LPS + stress showed an increase in the number of rearings compared to the groups SAL − stress (p < 0.01) and SAL + stress (p < 0.001). Also in the males, the group LPS + stress presented a reduction in the number of groomings compared to the group SAL − stress (p < 0.05). Regarding the time spent in the arena central area, females submitted to LPS + stress presented a reduction in this parameter compared to the groups SAL − stress (p < 0.001) and LPS − stress (p < 0.001). In the forced swimming test, the group of male LPS + stress presented an increase in the immobility time compared to the groups SAL − stress (p < 0.0001) and LPS − stress (p < 0.05). In females, the groups LPS − stress (p < 0.0001), SAL + stress (p < 0.01) and LPS + stress (p < 0.01) presented an increase in immobility time compared to the group SAL − stress. No significant alteration was observed in the sucrose consumption between the groups delineated in this study. Conclusions: Our results demonstrated that the animals submitted to neonatal LPS and peripubertal stress presented important behavioral alterations in adulthood, especially anxiouslike and negative-likeschizophrenia symptom. This conclusion is reinforced by the findings of increased immobility in the forced swimming test not accompanied by decreases in sucrose preference. Furthermore, LPS +stress group presented decreased number of grooming behavior. This calls attention for a possible loosing interest in everyday activities. The gender seems to influence the vulnerability to these events, since females were more vulnerable to the peripubertal stress than neonatal LPS to the development of anxious-like behavior, whilethe males showed
P.1.h. Basic and clinical neuroscience − Animal behaviour a possible synergistic effect between these two events to the development of negative-like symptoms. References [1] Andersen, S.L., 2003. Trajectories of brain development: Point of vulnerability or window of opportunity? Neurosci. Biobehav. Rev. 27, 3−18. [2] Ganguly, P., Brenhouse, H.C., 2014. Broken or maladaptive? Altered trajectories in neuroinflammation and behavior after early life adversity. Dev. Cogn. Neurosci. 11, 18−30. [3] Giovanoli, S., Engler, H., Engler, a., Richetto, J., Voget, M., Willi, R., Winter, C., Riva, M. a., Mortensen, P.B., Feldon, J., Schedlowski, M., Meyer, U., 2013. Stress in Puberty Unmasks Latent Neuropathological Consequences of Prenatal Immune Activation in Mice. Science (80). 339, 1095–1099. doi:10.1126/science.1228261.
P.1.h.048 The effect of one month riboflavin administration on thermo-nociceptive behavior and locomotion in mice C. Bohotin1,2 , T. Alexa2 , A. Luca1,2 ° , A. Dondas2 , D. Nebunu2 , R. Iliescu2,3 1 “Gr. T. Popa” University of Medicine and Pharmacy, Pathophysiology, Iasi, Romania; 2 “Gr. T. Popa” University of Medicine and Pharmacy, Centre for the Study and Therapy of Pain, Iasi, Romania; 3 “Gr. T. Popa” University of Medicine and Pharmacy, Pharmacology, Iasi, Romania Purpose: Certain neurotransmitters, including serotonin, norepinephrine or dopamine are metabolized by the monoamine oxidase (MAO), a mitochondrial outer membrane enzyme, dependent on FAD, the coenzyme form of riboflavin [1,2]. Riboflavin administration restores and stimulates MAO activity [3]. All MAOdependent neurotransmitters are involved in depression, pain and locomotion control. We therefore decided to explore the effect of repeated riboflavin administration (four weeks) on thermonociception, motor coordination and locomotor activity. Methods: 20 male BALB/c mice, weight 33±2 g, were divided in 2 groups: the riboflavin group (n = 12), and the control group (n = 8). The mice received daily riboflavin (50 mg/kg b.w.) or saline (the same volume as riboflavin treated mice) intraperitoneal injections and were evaluated for thermo-nociception, motor coordination and locomotor activity before treatment (baseline) and every two days thereafter, for a 28-day period. Nociception was evaluated using tail flick latency test (TFLT) and hot plate test (HPT). Motor coordination has been assessed by the rotarod test (RT). The Ugo Basile Activity Cage was used to measure horizontal (HLA) and vertical (VLA) locomotor activity. The cut off was set at 12s for TFLT, 15s for HPT and 300s for RT. The locomotor activity was evaluated for 3 minutes. The data for days 7, 14, 21, and 28 are presented in seconds and in percentage changes from baseline [PBC = (treated − baseline)×100/baseline]. Statistical significance was assessed by paired t-tests or ANOVA as appropriate. Results: Riboflavin had no statistically significant effect on thermo-nociception neither when compared with baseline nor with control group. However, the PBC for HPT in the saline group varied from −2% to +10%, while in the riboflavin group from −23% to 5%, whereas for TFLT, variations were 3−7.5% and −2−10%, respectively. We noticed a tendency towards hyperalgesia in the last week of treatment on the HPT. No changes on motor coordination were observed during riboflavin/saline treatment. By contrary, a significant decrease in rearing (day 28, −43.97±54.4%, p = 0.03) and horizontal movements (day 28,
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36.1±13%, p = 0.02) were noticed in the riboflavin-treated mice when compared with baseline or with control group. Starting from the first week, the decrease was significant for both vertical and horizontal movements. Briefly, our results show that one month of riboflavin treatment has no significant effects on nociception, no effect on motor coordination and has a powerful effect on mice’s exploratory behavior − the animals preferred to stay into the unprotected center area of the activity cage thus indicating that riboflavin has an anxiolytic-like behavior [3]. Conclusion: Even though riboflavin controls MAO metabolism through a mitochondrial FAD-dependent enzymes, it seems that it has different effects on MAO-dependent neurotransmitters, being more important for those involved in anxiety than those involved in pain and locomotion control. References [1] Zhou, B.P., Duane, A.L., Kwan S.W., 1995. Flavinylation of Monoamine Oxidase B J. Biol. Chem. 270: 23653–23660. [2] Edmondson, DE, Binda, C, Mattevi, A. 2004. The FAD binding sites of human monoamine oxidases A and B. Neurotoxicology 25, 63−72. [3] Bonnefil, V., Castiglione, CM, Cawthon, RM, Breakefield, XO 1981. Effect of riboflavin on monoamine oxidase activity in cultured neuroblastoma cells. Cell Mol Neurobiol 1, 351−9. [4] Bailey, K.R., Crawley, J.N., 2009. Anxiety-Related Behaviors in Mice. In:Buccafusco JJ, editor. Methods of Behavior Analysis in Neuroscience. 2nd edition. Boca Raton (FL):CRC Press/Taylor & Francis.
P.1.h.049 Electrical stimulation of the raphe magnus evoked changes in rats behaviour K. Ptaszek1 ° , E. Kurowska1 , M. Podlacha1 , J. Rucinski1 , E. Jurkowlaniec1 1 University of Gdansk Biology, Department of Animal and Human Physiology, Gdansk, Poland Serotonin (5-HT) regulates many fundamental aspects of physiology and behaviour including gastrointestinal functions and mood [1]. Peripheral 5-HT is synthesized and stored in the enterochromaffin cells found in the gastrointestinal tract crypts as well as in the platelets. In the central nervous system, fibers which are immunoreactive to 5-HT are widely distributed. However, the cells which produce 5-HT are found only in the restricted areas of the brain, namely in raphe nuclei groups which extend from the midbrain to the medulla. The raphe magnus (RMg) located in the B3 region has projection pathways mainly to the spinal cord [2]. The purpose of this study was to analyse the influence of electrical stimulation of the RMg on rats behaviour in three different modalities: learning, sociability and anxiety. The experiment was performed on a group of ten 3-month old male Wistar rats (weight ±250 g). Rats were implanted with electrodes into the RMg under isoflurane (1−2.5% in oxygen; Aerrane) anesthesia and butorphanol analgesia (1.5 mg/300 g b.w.; Butomidor). After 10-day convalescence, 16-day electrical stimulation was carried out at the intensity of stimulation current (60– 160 mA) determined individually for each rat. Rats were divided into stimulated (n = 7) and non-stimulated (sham, n = 3) groups. Every day, 25 stimulation trials were carried out, consisting of 30-second stimulation followed by 20-second interval. In the sham group, no current was passed through the electrode. During stimulations, the locomotor activity was measured by an actometer (Opto Varimex Minor). Furthermore, the rats’ memory (in the Morris Water Maze test; WM), anxiety level (in the Elevated Plus Maze test; EPM) and social responses (in the 3 chamber test; 3C) were analysed 30 minutes after stimulation trials on the 5th, 9th