Search results

1

Fluoro-Jade and TUNEL staining as useful tools to identify ischemic brain damage following moderate extradural compression of sensorimotor cortex

100%

Kundrotiene J., Wagner A., Liljequist S.

Acta Neurobiologiae Experimentalis

|

2004

|

vol. 64

|

issue 2

153-162

EN

Cerebral ischemia was produced by moderate compression for 30 min of a specific brain area in the sensorimotor cortex of Sprague-Dawley rats. On day 1, that is 24 h after the transient sensorimotor compression, ischemia-exposed animals displayed a marked focal neurological deficit documented as impaired beam walking performance. This functional disturbance was mainly due to contralateral fore- and hind-limb paresis. As assessed by daily beam walking tests it was shown that there was a spontaneous recovery of motor functions over a period of five to seven days after the ischemic event. Using histopathological analysis (Nissl staining) we have previously reported that the present experimental paradigm does not produce pannecrosis (tissue cavitation) despite the highly reproducible focal neurological deficit. We now show how staining with fluorescent markers for neuronal death, that is Fluoro-Jade and TUNEL, respectively, identifies regional patterns of selective neuronal death. These observations add further support to the working hypothesis that the brain damage caused by cortical compression-induced ischemia consists of scattered, degenerating neurons in specific brain regions. Postsurgical administration of the AMPA receptor specific antagonist, LY326325 (30 mg/kg; i.p, 70 min after compression), not only improved beam walking performance on day 1 to 3, respectively but also significantly reduced the number of Fluoro-Jade stained neurons on day 5. These results suggest that enhanced AMPA/glutamate receptor activity is at least partially responsible for the ischemia-produced brain damage detected by the fluorescent marker Fluoro-Jade.

2

Vesicular glutamate transporters (VGLUTs): the three musketeers of glutamatergic system

100%

Liguz-Lecznar M., Skangiel-Kramska J.

Acta Neurobiologiae Experimentalis

|

2007

|

vol. 67

|

issue 3

207-218

EN

Glutamate is the predominant excitatory neurotransmitter in the central nervous system (CNS) and glutamatergic transmission is critical for controlling neuronal activity. Glutamate is stored in synaptic vesicles and released upon stimulation. The homeostasis of glutamatergic system is maintained by a set of transporters present in plasma membrane and in the membrane of synaptic vesicles. The family of vesicular glutamate transporters in mammals is comprised of three highly homologous proteins: VGLUT1-3. The expression of particular VGLUTs is largely complementary with limited overlap and so far they are most specific markers for neurons that use glutamate as neurotransmitter. VGLUTs are regulated developmentally and determine functionally distinct populations of glutamatergic neurons. Controlling the activity of these proteins could potentially modulate the efficiency of excitatory neurotransmission. This review summarizes the recent knowledge concerning molecular and functional characteristic of vesicular glutamate transporters, their development, contribution to synaptic plasticity and their involvement in pathology of the nervous system.

3

Comparison of effects of endogenous and exogenous excitatory amino acids on retzius nerve cells of the leech

88%

Lopicic S., Nedeljkov V., Cemerikic D., Dudvarski Z., Pavlovic D., Cutura N.

Folia Biologica

|

2009

|

vol. 57

|

issue 1-2

83-90

EN

In this paper we examine the effects of L-aspartate, L-glutamate, and beta-N-oxalylamino-L-alanine (Lathyrus toxin) on Retzius nerve cells of the leech Haemopis sanguisuga. The goal was to compare the electrophysiological effects of endogenous vs. exogenous amino acids, known as potent neurotoxins, through themechanismof excitotoxicity.We used classical intracellular recordings on Retzius nerve cells in isolated ganglia of the leech, and plotted dose-response curves to compare potencies. Our results show that Lathyrus toxin is more than 200 times more potent in depolarizing the membrane potential on our model than L-aspartate and L-glutamate, which are approximately equipotent.

4

Putative transmitter systems of mammalian sympathetic preganglionic neurons

88%

Dun N. J., Karczmar A. G., Wu S.-Y., Shen E.

Acta Neurobiologiae Experimentalis

|

1993

|

vol. 53

|

issue 1

53-63

EN

The sympathetic nervous system evokes complex effects at multiple target organs in response to external, internal as well as mental stimuli. This output involves an interplay between the actions of a number of transmitters and modulators and a the postsynaptic and presynaptic sites of the autonomic ganglia and the sympathetic preganglionic neurons (SPNs). This review concerns particularly the SPNs of the cat and neonatal rat, studied by means of electrophysiological and immunohistochemical methods. Four types of responses may be elicited, the fast EPSP and IPSP, and their currents and the slow ESPSPs and IPSPs, and their currents. Glutamate and glycine appear to mediate the fast excitatory and inhibitory responses, respectively; peptides and amines seem to be responsible for generating the slow excitatory response, while the slow inhibitory response, found so far only in the cat, appears to be mediated by norepinephrine. Finally, glutamate, enkephalin and GABA, but not glycine attenuate the release of the inhibitory and excitatory transmitters from the nerve terminals abutting on the SPNs. The supraspinal efferent and afferent projections which may release the transmitters and modulators in question are discussed, as well the mechanisms that ensure appropriate programming and moment-to-moment regulation of the autonomic output.

5

The effects of glutamate ionophoresis on single cell responses and inter-neuronal interactions in the kitten visual cortex

88%

Michalski A., Kraszewski K.

Acta Neurobiologiae Experimentalis

|

1995

|

vol. 55

|

issue 2

85-97

EN

There was studied the effect of glutamate micro-ionophoresis on visual responses (PSTHs) and cross-correlograms of neurones recorded simultonously in the cortex of 4-6 week old kittens.PSTHs and cross-correlograms were tested before,during and after glutamate injections and compared with adult cats data from previous experiment.

6

The role of nitric oxide in the physiological and pathological functions of the central nervous system

88%

Tutka P., Kleinrok Z.

Postępy Higieny i Medycyny Doświadczalnej

|

1995

|

vol. 49

|

issue 2

189-199

7

Concanavalin A enhances quisqualate-induced calcium influx in cerebellar granule cells in culture

88%

Danysz W., Raulli R., Wroblewski J. T.

Acta Neurobiologiae Experimentalis

|

1996

|

vol. 56

|

issue 3

649-656

EN

In primary cultures of cerebellar granule cells kainate produced marked influx of 45Ca2+, partially sensitive to the N-methyl-D-aspartate (NMDA) antagonist, 3-(?)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP), indicating involvement of an NMDA receptor-sensitive component that may be secondary to kinate-induced glutamate release.Sodium removal partially inhibited kainate's effect.Quisqualate also produced influx of 45Ca2+, but with lower efficiacy and higher potency than kainate.This action of quiqualate was uneffected by CPP and by sodium removal.Preincubation of cells with the plant lectin concavalin A(Con A), but not with irs succinyl derivative, enhanced quisqualate -induced calcium influx, and to a lesser extend kainate' effect.Inclusion of quisqualate in preincubation medium antagonized Con A potention of quisqualate response.Also Con A was ineffective when included in the incubation medium only, without preincubation.Preincubation of rat brain cortical membranes with Con A but not with succinyl Con A increased the binding of the AMPA receptor agonist. The results suggest that Con A enhancement of quisqualate response possibly involves the modification of an AMPA recogintion site requires preincubation in the absence of an agonist (here quisqualate).

8

Preconditioning reduces hypoxia-evoked alterations in glutamatergic Ca2+ signaling in rat cortex

75%

Semenov D. G., Samoilov M. O., Lazarewicz J. W.

Acta Neurobiologiae Experimentalis

|

2008

|

vol. 68

|

issue 2

169-179

EN

The aims of this study were (1) to characterize calcium signaling in rat cortex induced by repeated in vitro application of the glutamatergic agonists L-glutamate, NMDA, AMPA and DHPG, (2) to analyze the influence of transient severe hypobaric hypoxia (180 Torr) administered in vivo on calcium responses to stimulation of glutamate receptors by their agonists, and (3) to evaluate the effects of preconditioning with intermittent mild hypobaric hypoxia (360 Torr), 24 h before the severe hypoxia, on these Ca2+ responses. Intracellular Ca2+ dynamics was studied using the fluorescent probes fura-2 and chlortetracycline to monitor free and bound calcium (Cai and Cab), respectively. In control cortical slices, application of L-glutamate, NMDA and AMPA induced concomitant increases in Cai and Cab, reflecting Ca2+ influx and its intracellular accumulation in neurons. DHPG, an agonist of group I mGlu receptors induced a decrease in Cab accompanied by a rise in Cai levels, indicating Ca2+ mobilization. In cortical slices collected 24 h after severe hypoxia, the responses of Cab to glutamate administration were increased, DHPG-induced shifts were reversed, the increase in Cab after the first application of AMPA was reduced, while after the second, Cab rises were potentiated, and the increases in Cab evoked by NMDA application were slightly suppressed. The alterations of responses in Cab to the selective agonists were completely prevented by preconditioning with mild hypoxia. Our results suggest that protection of normal glutamatergic calcium signaling contributes to tolerance to hypoxia induced by preconditioning.

Refine search results

Fluoro-Jade and TUNEL staining as useful tools to identify ischemic brain damage following moderate extradural compression of sensorimotor cortex

Vesicular glutamate transporters (VGLUTs): the three musketeers of glutamatergic system

Comparison of effects of endogenous and exogenous excitatory amino acids on retzius nerve cells of the leech

Putative transmitter systems of mammalian sympathetic preganglionic neurons

The effects of glutamate ionophoresis on single cell responses and inter-neuronal interactions in the kitten visual cortex

The role of nitric oxide in the physiological and pathological functions of the central nervous system

Concanavalin A enhances quisqualate-induced calcium influx in cerebellar granule cells in culture

Preconditioning reduces hypoxia-evoked alterations in glutamatergic Ca2+ signaling in rat cortex