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TrkB signaling. Dynamic changes induced by zinc deficiency
The Twenty-second Day of Neuropsychopharmacology Posters
glycolytic enzymes in the frontal cortex and the hippocampus of adult control and prenatally stressed rats. Since prenatal exposure to glucocorticoids may not change the level of the investigated enzymes in basal condition, our studies were also conducted in adult animals subjected to acute stress and in rats after oral glucose administration. Pregnant Sprague Dawley rats were submitted to three daily stress session – from 14th day of pregnancy until delivery. Control animals were left undisturbed in their home cages. At 3 months of age, after behavioral verification, some rats were subjected to immobility stress while other received glucose (2.5 mg/kg, oral). Prenatally stressed rats were characterized by elevated glucose level in the frontal cortex and hippocampus. Prenatal stress also increased phosphofructokinase concentration in both examined brain tissues. Prenatal stress did not change the level of pyruvate kinase, while immobility
stress reduced the levels of this enzyme both in control and prenatally stressed rats. The obtained results suggest, that elevated glucose concentrations in the brain structures of prenatally stressed rats may not be a result of the impairment of glycolysis since the level of none of the key enzymes of this process was reduced. Instead, the level of the most important glycolytic enzyme, phosphofructokinase, increased in the animals subjected to prenatal and immobility stress, and this change was stronger in the hippocampus than in the frontal cortex. Thus, the elevated brain glucose concentration may be connected with processes other than glycolysis, such as gluconeogenesis or an increase in glucose uptake.
Acknowledgments: This work was supported by the Operating Program of Innovative Economy 2007–2013, grant No. POIG.01.01.02-12-004/09.
The disruption of CREB/BDNF/TrkB signaling. Dynamic changes induced by zinc deficiency Urszula Doboszewska1,2, Bernadeta Szewczyk1, Magdalena Sowa-Kuæma1, Katarzyna M³yniec3, Gabriel Nowak1,2 Department
of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smêtna 12, PL 31-343 Kraków, Poland; Department of Pharmacobiology, !Department of Biochemical Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, PL 30-688 Kraków, Poland
Background: Our previous studies indicated that expression of several proteins involved in numerous aspects of plasticity in the central nervous system (CNS) is modulated by four-week dietary deprivation of trace element zinc. The levels of the phosphorylated forms of transcription factor cyclic AMP response-element binding (pCREB) protein, neurotrophin brain derived neurotrophic factor (BDNF) protein and high-affinity tropomyosine-related kinase B receptor (TrkB) protein were significantly decreased in the hippocampus of rats fed a zinc-deficient diet for four weeks. However, no changes of these proteins between rats subjected to four-week zinc restriction and the control animals were found in the prefrontal cortex. Aims: Here we examined whether six-week dietary zinc deprivation induces changes in the protein levels
of pCREB, BDNF and TrkB in the prefrontal cortex and hippocampus of rats. Methods: Male Sprague Dowley rats (5-week-old) were fed a 50 mg Zn/kg (control group) or a 3 mg Zn/kg (zinc deficient group) diet for six weeks. The protein levels of pCREB, BDNF and TrkB were measured using western blotting. Results: The levels of pCREB and BDNF proteins were significantly decreased (by 46% and 52%) in the prefrontal cortex and (by 44% and 54%) in the hippocampus of rats subjected to six-week zinc-deficient diet when compared with that of the control animals. Interestingly, at the same time point an increase (by 153%) in TrkB protein was observed in the prefrontal cortex of group fed zinc-deficient diet for six weeks compared to the control group.
Pharmacological Reports, 2013, 65, suppl.
119
Conclusions: The present data reports that six-week dietary zinc deprivation, unlike four-week zinc restriction, influences not only the hippocampus, but also the prefrontal cortex of rats. One can assume that CREB/ BDNF/TrkB proteins levels changes are dynamic in response to zinc deprivation and vary not only across brain regions but also in the course of time.
Acknowledgments: Urszula Doboszewska acknowledges the financial support from the project Interdisciplinary PhD Studies “Molecular sciences for medicine” (co-financed by the European Social Fund within the Human Capital Operational Programme).
Comparison of NOS and COX isoenzymes levels in brain structures involved in response to acute stress Anna G¹dek-Michalska, Paulina Rachwalska, Joanna Tadeusz, Jan Bugajski Department of Physiology, Institute of Pharmacology, Polish Academy of Sciences, Smêtna 12, PL 31-343 Kraków, Poland
Inducible isoforms of nitric oxide synthase and cyclooxygenase are expressed by specific stress mediators in different brain regions as a general response to stress. The aim of this study was to evaluate the involvement of constitutive and inducible cyclooxygenase (COX-1 and COX-2) and neuronal and inducible nitric oxide synthase (nNOS and iNOS) isoenzymes in acute restraint stress effect on prostaglandins (PG) and nitric oxide (NO) systems in brain structures involved in stress response. Rats were restrained in metal tubes for 10 min and nNOS, iNOS, COX-1 and COX-2 isoenzymes in prefrontal cortex, hippocampus and hypothalamus were determined immediately after stress termination and 1, 2 and 3 h later. As a result of restraint stress for 10 min, COX-1 level in prefrontal cortex and hypothalamus significantly increased. In hippocampus changes in COX-1 levels were not significant. COX-2 level in prefrontal cortex slightly de-
120
Pharmacological Reports, 2013, 65, suppl.
creased in comparison with non-stressed rats, while in hippocampus COX-2 level remained increased. In hypothalamus restraint stress markedly increased COX-2 level 2 and 3 h after termination of stress. In prefrontal cortex, acute restraint stress immediately after its termination induced a moderate increase in both nNOS and iNOS levels with followed significant decrease 1–2 h and recovery at 3 h after stress period. In hippocampus a marked increase in nNOS level coincided with decrease in iNOS level 2 h after cessation of stress. In hypothalamus restraint stress markedly increased nNOS level at the termination of stress. These results indicate that acute stress functionally affect the COX/PG and NOS/NO systems in brain.
Grant POIG 01.01.02-12-004/09-00 financed by European Regional Development Fund.
glycolytic enzymes in the frontal cortex and the hippocampus of adult control and prenatally stressed rats. Since prenatal exposure to glucocorticoids may not change the level of the investigated enzymes in basal condition, our studies were also conducted in adult animals subjected to acute stress and in rats after oral glucose administration. Pregnant Sprague Dawley rats were submitted to three daily stress session – from 14th day of pregnancy until delivery. Control animals were left undisturbed in their home cages. At 3 months of age, after behavioral verification, some rats were subjected to immobility stress while other received glucose (2.5 mg/kg, oral). Prenatally stressed rats were characterized by elevated glucose level in the frontal cortex and hippocampus. Prenatal stress also increased phosphofructokinase concentration in both examined brain tissues. Prenatal stress did not change the level of pyruvate kinase, while immobility
stress reduced the levels of this enzyme both in control and prenatally stressed rats. The obtained results suggest, that elevated glucose concentrations in the brain structures of prenatally stressed rats may not be a result of the impairment of glycolysis since the level of none of the key enzymes of this process was reduced. Instead, the level of the most important glycolytic enzyme, phosphofructokinase, increased in the animals subjected to prenatal and immobility stress, and this change was stronger in the hippocampus than in the frontal cortex. Thus, the elevated brain glucose concentration may be connected with processes other than glycolysis, such as gluconeogenesis or an increase in glucose uptake.
Acknowledgments: This work was supported by the Operating Program of Innovative Economy 2007–2013, grant No. POIG.01.01.02-12-004/09.
The disruption of CREB/BDNF/TrkB signaling. Dynamic changes induced by zinc deficiency Urszula Doboszewska1,2, Bernadeta Szewczyk1, Magdalena Sowa-Kuæma1, Katarzyna M³yniec3, Gabriel Nowak1,2 Department
of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smêtna 12, PL 31-343 Kraków, Poland; Department of Pharmacobiology, !Department of Biochemical Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, PL 30-688 Kraków, Poland
Background: Our previous studies indicated that expression of several proteins involved in numerous aspects of plasticity in the central nervous system (CNS) is modulated by four-week dietary deprivation of trace element zinc. The levels of the phosphorylated forms of transcription factor cyclic AMP response-element binding (pCREB) protein, neurotrophin brain derived neurotrophic factor (BDNF) protein and high-affinity tropomyosine-related kinase B receptor (TrkB) protein were significantly decreased in the hippocampus of rats fed a zinc-deficient diet for four weeks. However, no changes of these proteins between rats subjected to four-week zinc restriction and the control animals were found in the prefrontal cortex. Aims: Here we examined whether six-week dietary zinc deprivation induces changes in the protein levels
of pCREB, BDNF and TrkB in the prefrontal cortex and hippocampus of rats. Methods: Male Sprague Dowley rats (5-week-old) were fed a 50 mg Zn/kg (control group) or a 3 mg Zn/kg (zinc deficient group) diet for six weeks. The protein levels of pCREB, BDNF and TrkB were measured using western blotting. Results: The levels of pCREB and BDNF proteins were significantly decreased (by 46% and 52%) in the prefrontal cortex and (by 44% and 54%) in the hippocampus of rats subjected to six-week zinc-deficient diet when compared with that of the control animals. Interestingly, at the same time point an increase (by 153%) in TrkB protein was observed in the prefrontal cortex of group fed zinc-deficient diet for six weeks compared to the control group.
Pharmacological Reports, 2013, 65, suppl.
119
Conclusions: The present data reports that six-week dietary zinc deprivation, unlike four-week zinc restriction, influences not only the hippocampus, but also the prefrontal cortex of rats. One can assume that CREB/ BDNF/TrkB proteins levels changes are dynamic in response to zinc deprivation and vary not only across brain regions but also in the course of time.
Acknowledgments: Urszula Doboszewska acknowledges the financial support from the project Interdisciplinary PhD Studies “Molecular sciences for medicine” (co-financed by the European Social Fund within the Human Capital Operational Programme).
Comparison of NOS and COX isoenzymes levels in brain structures involved in response to acute stress Anna G¹dek-Michalska, Paulina Rachwalska, Joanna Tadeusz, Jan Bugajski Department of Physiology, Institute of Pharmacology, Polish Academy of Sciences, Smêtna 12, PL 31-343 Kraków, Poland
Inducible isoforms of nitric oxide synthase and cyclooxygenase are expressed by specific stress mediators in different brain regions as a general response to stress. The aim of this study was to evaluate the involvement of constitutive and inducible cyclooxygenase (COX-1 and COX-2) and neuronal and inducible nitric oxide synthase (nNOS and iNOS) isoenzymes in acute restraint stress effect on prostaglandins (PG) and nitric oxide (NO) systems in brain structures involved in stress response. Rats were restrained in metal tubes for 10 min and nNOS, iNOS, COX-1 and COX-2 isoenzymes in prefrontal cortex, hippocampus and hypothalamus were determined immediately after stress termination and 1, 2 and 3 h later. As a result of restraint stress for 10 min, COX-1 level in prefrontal cortex and hypothalamus significantly increased. In hippocampus changes in COX-1 levels were not significant. COX-2 level in prefrontal cortex slightly de-
120
Pharmacological Reports, 2013, 65, suppl.
creased in comparison with non-stressed rats, while in hippocampus COX-2 level remained increased. In hypothalamus restraint stress markedly increased COX-2 level 2 and 3 h after termination of stress. In prefrontal cortex, acute restraint stress immediately after its termination induced a moderate increase in both nNOS and iNOS levels with followed significant decrease 1–2 h and recovery at 3 h after stress period. In hippocampus a marked increase in nNOS level coincided with decrease in iNOS level 2 h after cessation of stress. In hypothalamus restraint stress markedly increased nNOS level at the termination of stress. These results indicate that acute stress functionally affect the COX/PG and NOS/NO systems in brain.
Grant POIG 01.01.02-12-004/09-00 financed by European Regional Development Fund.