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Encoding meal in integrated vagal afferent discharge

100%

Krolczyk G., Zurowski D., Sobocki J., Laskiewicz J., Thor P. J.

Journal of Physiology and Pharmacology

2004

tom 55

nr 1,1

Vagal afferents are integral part of the negative feedback loop induced by constitution and size of food stomach and jejunum. Aim of this study was to assess vagal discharge in response to food and gastric distension in rats. Electrophysiological recordings of vagal afferents in fasted (n=32), fed rats (n=20) and during gastric balloon distension (n=12) were performed. After 60 minutes of fasted nerve recording tube feeding was done. Fasted rats also underwent gastric distension via oesophagus. Vagal afferents discharges were analysed with dual time-amplitude window discriminator. Total vagal afferent discharge in fasted and fed rats revealed 0.3 ± 0.12 vs 0.56 ± 0.22 Hz (p<0.05). We observed two distinct discharge patterns: high amplitude low frequency (HALF) and low amplitude high frequency (LAHF). HALF spikes were observed more frequent in fasted than in fed rats (0.05 ± 0.02 vs. 0.03 ± 0.016 Hz (p<0.05). Conversely LAHF spikes in fed rats predominated over their occurrence in fasted rats: 0.52 ± 0.2 vs. 0.25 ± 0.12 Hz (p<0.05). Left vagal afferents discharge rises with gastric distension of 6, 8 and 10 ml and were: 0.46 ± 0.22 Hz, 0.65 ± 0.31 Hz, 0.86 ± 0.33 Hz (p<0.05) respectively. Similar discharge showed right vagal afferents: 0.41 ± 0.08 Hz, 0.51 ± 0.13 Hz and 0.77 ± 0.27 Hz (p<0.05) for 6, 8 and 10 ml of distension, respectively. We conclude that interdigestive information from gastrointestinal tract is encoded in high amplitude low frequency of spikes pattern in the vagus nerves.

Oscillatory cortical activities in the gamma band in the human EEG induced by visual stimuli - representation of the stimulus?

51%

Muller M. M.

Acta Neurobiologiae Experimentalis

2000

tom 60

nr 1

The present work presents three experiments investigating cortical activities in the gamma band in humans. On the basis of theoretical models and animal experiments, synchronized oscillatory neuronal activity is discussed as the key mechanism by which the brain binds information processesed in different cortical areas to form a percept. Using an identical stimulation design - the same as used in animal studies - it was shown that induced gamma band responses in the EEG resemble the same features as those found in the intracortical recordings of animals. In addition, the present work demonstrates that these cortical activities are not higher harmonics of the alpha band and that they are senstive to the features of the stimulus. These results support the notion that gamma band activity is not just a by-product of neuronal activity and that alpha- and gamma band activies most certainly represent different cortical funtional states.

Effects of DAGO on the rodent hippocampal evoked potentials using different perfusion solutions

51%

SanMartin S., Menendez L., Gutierrez M., Hidalgo A., Baamonde A.

Acta Neurobiologiae Experimentalis

2000

tom 60

nr 2

Opioid receptor agonists exert excitatory effects in the hippocampus by inhibiting GABA release. We report that the |Li-opioid agonist, DAGO, increases the amplitude of the population spikes (PS) measured in the stratum pyramidale of the CA1 cell layer in mouse and rat hippocampal slices perfused with an artificial cerebrospinal fluid (ACSF), but not when perfused in Krebs solution. The GABAa agonist, 3-APS, induces inhibitory responses when perfused in either ACSF or Krebs. Also, the field excitatory postsynaptic potentials (EPSP) measured on stratum radiatum do not differ when the slice is perfused with either ACSF or Krebs. The increase in the amplitude of the PS induced by DAGO is not obtained when perfused in a modified ACSF whose concentration of MgS04 was lowered to its concentration in the Krebs solution (from 2.4 mM to 1.2 mM). Thus, changes in the concentration of MgS04 seem to be responsible for the different responses induced by DAGO.

Ograniczanie wyników

2 Acta Neurobiologiae Experimentalis

1 Journal of Physiology and Pharmacology

1 Baamonde A.

1 Gutierrez M.

1 Hidalgo A.

1 Krolczyk G.

1 Laskiewicz J.

1 Menendez L.

1 Muller M. M.

1 SanMartin S.

1 Sobocki J.

1 Thor P. J.

1 Zurowski D.

1 2004

2 2000

Wyniki wyszukiwania

Encoding meal in integrated vagal afferent discharge

Oscillatory cortical activities in the gamma band in the human EEG induced by visual stimuli - representation of the stimulus?

Effects of DAGO on the rodent hippocampal evoked potentials using different perfusion solutions