Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 2

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Inhibition of mGluR5 but not mGluR1 disrupts memory retrieval in the one-trial passive avoidance task in one-day old chicks

100%
Gieros K., Sobczuk A., Salinska E.
Acta Neurobiologiae Experimentalis
|
2011
|
tom 71
|
nr 1
It is known, that group I metabotropic glutamate receptors (mGluRs) are involved in memory consolidation and reconsolidation. The Ca2+ signal derived from IP3 receptors (IP3R) stimulation via mGluRs activation, initiates protein synthesis that is necessary for complete memory consolidation, whereas it is suggested that during retrieval and reconsolidation of memory other mGluR1/5 triggered mechanisms may be involved. Recently mGluRs have received considerable attention as a potential drugs target for many neurological disorders, but their influence on learning and memory is still unclear. With the increasing number of people suffering memory dysfunction of different origin, unravelling of the mGluRs role in memory processes may be very important. The aim of this study was to detect differences in the role for mGluR1 and mGluR5 in memory retrieval at different times after initial training and remainder of the task. One-day old chicks were trained to avoid pecking metal bead covered with bitter-tasting substance methylanthranilate. Two experimental groups were given a reminder by presenting similar metal bead 2 or 24 h after initial training. Bilateral injections of mGluR1 antagonist LY367385 (7.5 nmol/hemisphere), mGluR5 antagonist MPEP (20 nmol/hemisphere) or IP3R antagonist 2-APB (2.5 nmol/ hemisphere) were made directly into the IMM region of chick brain. Injections were made immediately after initial training or reminder, and at 2, 3 and 24 hours later. Our results demonstrate, that in the one-trial passive avoidance task in chicks, injection of the mGluR1 and mGluR5 antagonists into chick brain region IMM shortly after training resulted in permanent amnesia. Injection of MPEP at other times (2, 3 and 24 h after initial training) resulted in transient amnesia observed 1-2 h after injection and lasting up to 4 hours. The same effect was observed for 2-APB. Blocking mGluR1 and mGluR5 immediately after reminder resulted in similar transient amnesia, same as blocking IP3R. Injections of MPEP or 2-APB at later times after reminder also resulted in transient amnesia, however the effect was weaker when reminder was given 24 h after training. mGluR1 antagonist applied later than in a short time after training or reminder had no effect on memory recall. Presented data suggest that at least in the chick model, activation of mGluR1 and mGluR5 is necessary for complete memory consolidation and reconsolidation, whereas mGluR5 are additionally involved in retrieval processes which is dependent on Ca2+ release from IP3 activated intracellular calcium stores.
2

Hyperbaric preconditioning combined with post-ischemic hyperbaric therapy prevents ischemia-evoked damage to CA1 hippocampal neurons of Mongolian gerbils

76%
Malek M., Gamdzyk M., Duszczyk M., Ziembowicz A., Sobczuk A., Lazarewicz J., Salinska E.
Acta Neurobiologiae Experimentalis
|
2011
|
tom 71
|
nr S
Lack of the clinically effective pharmacological neuroprotection in different forms of brain ischemia increased the interest in alternative methods of therapy, like hypothermia or induction of brain tolerance by pre- and post-conditioning. The hyperbaric oxygen (HBO) therapy (2.5 atm) applied after ischemia or traumatic brain injury is one of the proposed but still controversial methods. The aim of this study was to find whether HBO and hyperbaric air (HBA) preconditioning followed by hyperbaric treatment applied for 60 min at different times after 3 min forebrain ischemia in gerbils will give a significant protection. The effects of both treatments on brain temperature and animal behaviour were also examined. A telemetric system to measure brain temperature was used and for behavioural observations a nest building test. The density of viable CA1 pyramidal neurons was also quantified. Our results show that HBO preconditioning combined with HBO postischemic therapy significantly reduced ischemia-evoked increase of brain temperature. HBA was also effective. Both treatments significantly increased gerbils’ ability to build a nest in comparison to untreated animals. The best effect was observed when postischemic therapy was applied 1 h after ischemia, but it was also effective 3 h after ischemia. Morphological analysis showed that HBO preconditioning combined with HBO postischemic treatment applied 1 h after ischemia significantly reduced neuronal damage in CA1 region of hippocampus resulting in 85% of surviving neurons compared to 18% of surviving CA1 neurons in the brains of animals subjected to ischemia but not treated with HBO. Our results show that HBO preconditioning combined with HBO therapy after forebrain ischemia in gerbils gives morphological protection which is accompanied by good behavioral results. Apart from inducing tolerance mediated by mild oxidative stress, HBO may affect blood oxygenation and other factors instrumental in brain protection.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.