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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.

The role of sensory C-fibers in response of vagal afferent stimulation by gastric distension in rats with experimental chronic gastric ulcer

63%

Zurowski D., Dobrek L., Bugajski A., Thor P. J.

Journal of Physiology and Pharmacology. Supplement

2008

tom 59

nr 2

There is growing evidence that gastric vagal afferent input may contribute to the altered sensations associated with gastrointestinal disorders. The aim of our study was to evaluate gastric vagal afferents (VA) activity in rats with experimental gastric ulcer and ulcer healing. The study was carried out on rats with gastric ulcer (GU), including, a group with perivagal capsaicin pretreatment (CAP), a group with capsaicin administration in gastric ulcer (CAP+GU) animals and control rats. In all rats electrical VA activity was recorded and analysed. In GU rats recordings were carried out in chronic ulcer and ulcer healing. In GU and CAP+GU groups gastric balloon distensions with vagal recording was performed on 3rd day after ulcer induction. Usually, experimental GU healed spontaneously within 2 weeks. Three days after acetic acid application when GU fully develop, the frequency of the basal VA activity was almost 3-times higher than in the control intact rats and remained elevayed until 4th week after ulcer induction. VA response to gastric distension increased concomitantly with increased balloon volume in both GU and control animals, but it was several times higher in GU rats. Perivagal capsaicin application decreased the frequency of spontaneous VA activity and decreased the response of VA to gastric distension. In CAP+GU, spontaneous activity as well as the response to gastric distension were higher than in CAP rats. Our study shows that GU induced inflammatory changes increase sensitivity of gastric VA. Capsaicin-sensitive vagal afferent fibers may play some role in this phenomenon. Peripheral sensitization of VA persists even when gastric ulcer is completely healed.

Peripheral mechanisms of intestinal dysmotility in rats with salsolinol induced experimental Parkinson's disease

63%

Banach T., Zurowski D., Gil K., Krygowska-Wajs A., Marszalek A., Thor P. J.

Journal of Physiology and Pharmacology

2006

tom 57

nr 2

Gastrointestinal dysmotility in Parkinson's disease (PD) has been attributed in part to peripheral neurotoxine action. Our purpose was the evaluation of the salsolinol effect on intramuscular interstitial cells of Cajal (ICC), duodenal myoelectrical activity (DMA) and vagal afferent activity (VAA) in rats with experimental PD. Twenty rats were divided into 2 equal groups. Experimental PD was produced in one group by 3 weeks of the intraperitoneal salsolinol injections (50 mg/kg/day), whereas the 2-nd group served as control. DMA and VAA were recorded in both groups during fasting and stepwise - gastric distension (GD) of 10 ml. Subsequently fragments of duodenum were removed and intramuscular ICC were assessed as c-Kit antigen percentage in the duodenal muscular zone. Analyses of the fasting DMA and VAA recordings didn't reveal differences between the compared groups. During GD increase of DMA dominant frequency (p=0.04) and VAA frequency (p<0.01) was observed in the controls whereas in the salsolinol group both parameters remained unchanged. Image analysis of duodenum revealed decreased c-Kit expression in the salsolinol-injected animals (p=0.05). The results of our study may suggest the direct effect of salsolinol on both ICC and neuronal pathways of gastro-duodenal reflexes.

Ograniczanie wyników

2 Journal of Physiology and Pharmacology

1 Journal of Physiology and Pharmacology. Supplement

3 Thor P. J.

3 Zurowski D.

1 Banach T.

1 Bugajski A.

1 Dobrek L.

1 Gil K.

1 Krolczyk G.

1 Krygowska-Wajs A.

1 Laskiewicz J.

1 Marszalek A.

1 Sobocki J.

1 2008

1 2006

1 2004

Wyniki wyszukiwania

Encoding meal in integrated vagal afferent discharge

The role of sensory C-fibers in response of vagal afferent stimulation by gastric distension in rats with experimental chronic gastric ulcer

Peripheral mechanisms of intestinal dysmotility in rats with salsolinol induced experimental Parkinson's disease