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D Zurowski

Publications and source records attributed to D Zurowski.

10 recordsLinked to original sources
PubMed2006

Peripheral mechanisms of intestinal dysmotility in the morphine tolerant and dependent rats.

Changes of intestinal motility and transit produced by tolerance to and dependence upon morphine have been partly attributed to peripheral mechanisms. We evaluated the effect of chronic peripheral morphine administration and peripheral mu-receptor blockade on vagal afferent activity (VAA) and c-Kit positive intramuscular cells of Cajal (ICCs). Ten rats were subjected to chronic subcutaneous morphine infusion for 72 h with subsequent VAA recording. Potential frequency was evaluated within recordings before and after mu receptor blockade by (D)-Phe -Cys -Tyr -(D)-Trp -Orn -Thr -Phe -Thr (CTOP) i.p. injections. Afterwards the rats were sacrificed and intramuscular c-Kit antigen expression was assessed by image analysis within removed fragments of duodenum and ascending colon. An equal group of rats served as a control for VAA and c-Kit expression. Analysis of VAA revealed similar frequencies of potentials in morphine tolerant / dependent rats before CTOP and in the controls. CTOP increased potential frequency in the morphine group which effect was visible mostly within the first 20 minutes (p=0.01). The morphine infused animals presented also higher c-Kit expression in both the duodenum (p<0.001) and the ascending colon (p<0.001) in comparison to the control group. Results of our study may indicate the involvement of both the intestinal wall and the long vago-vagal reflexes in tolerance to and dependence upon opioids.

Animals↗
PubMed2006

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

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.

Animals↗
PubMed2004

Encoding meal in integrated vagal afferent discharge.

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.

Action Potentials↗
PubMed2004

Capasaicin induced deafferentation enhances the effect of electrical vagal nerve stimulation on food intake and body mass.

Study was based on hypothesis that electrical stimulation (ES) with parameters obtained from analysis of vagal afferent discharge fed state may fake brain with satiety state. We evaluated effect of denervation of vagal capsaicin-sensitive afferents on food intake and body weight in rats with ES of vagal nerves using microchip (MC). Group A was scheduled to MC implantation, B to sham operation only, C to MC implantation and capsaicin vagal deafferentation, and D to capsaicin denervation only. ES lasted 24 days. MC parameters were 0.05 Hz, 0.1s, 0.55 V. ES of left vagus significantly reduced total food intake as well as the mean daily intake in groups A and C in comparison to control and D group (ANOVA, F=18.55, p=0.0038). Body weight was lower in group A (3462 g) and C (2727 g) then in control (3814 g) and D (3568 g) (F=25.68, p=0.00068). Leptin decreased in C (165 pg/mL) in comparison to A (625 pg/mL), B (677 pg/mL), and D (612 pg/mL) (p<0,05), mainly due to ES (F=7.27, p=0.019). Glucose was decreased in A (F=5.55, p=0.036) - by 11% and by 16% in C group. Proper vagal neuromodulation results in central and peripheral effects causing food intake and body weight downregulation.

Administration, Topical↗
PubMed2001

[Interstitial cells of Cajal and their pacemaker function].

Interstitial cells of Cajal are known more than 100 years. These cells are proved now as slow wave pacesetters. Ultrastructure and physiologic pacemaker's activity is well described by many authors. Dysfunction of these cells is associated with different pathological states in gastrointestinal tract. Strong relationships between GI motility diseases and qualitative and quantitative changes of ICC are observed. Nowadays most of the gastroenterologists agree that evaluation of these cells should become routine diagnostic procedure. We gave a short review of recent achievements and ideas on interstitial cells of Cajal function in gastroenterology.

Animals↗
PubMed2001

[Effect of chemical sympathectomy on myoelectric activity of the small bowel].

UNLABELLED: Central and peripheral noradrenergic system modulates myoelectric activity of the small bowel. Aim of this study was to evaluate the role of peripheral noradrenergic system in modulation of slow waves activity. Recordings of slow waves were performed on 20 conscious rats chronically fitted with 2 unipolar electrodes. After controls recording the animals were injected i.p. with 6-hydroxydopamine (6-OHDA--Sigma H8523) and the recording were performed on daily basis through the period of one month. RESULTS: The increase of frequency slow waves during the first week after 6-OHDA from 0.61 (+/- 0.11) to 0.71 (+/- 0.03), (p. < 0.05), and amplitude from 14468 +/- 11196 to 19128 +/- 5282 (microV)2 (p > 0.05) were observed. Variability in control recording was higher (SD +/- 0.11) than after 6-OHDA (SD 0.03). Next day diarrhoea after 6-OHDA occurred, persisted despite return normal myoelectric activity. Slow waves frequency gradually returns to control value after the fourth week. CONCLUSION: Peripheral noradrenergic system has a significant effect on the frequency and variability of slow wave and minor role on its amplitude but no on diarrhoea pattern.

Animals↗
PubMed2001

[The role of leptin in metabolic regulation].

Leptin discovery--the hormone derived from adipose tissue became a challenging event in understanding food intake and energy balance regulation. Leptin serum level correlates with fat stores and reacts according to changes in energy balance. Although leptin is thought of as a factor preventing obesity, in most of the cases obesity develops in association with increase in serum leptin level which indicates leptin resistance. It may be possible that the primary role of leptin is to mediate the signal for the switch between the starved and fed state. There is a lot of evidence that leptin has systemic effects apart from those related to energy homeostasis, including regulation of neuroendocrine, immune and reproductive function.

Adipose Tissue↗
PubMed2001

Effects of continuous microchip (MC) vagal neuromodulation on gastrointestinal function in rats.

Afferent fibers from gastrointestinal tract outnumber efferents ten times in vagal nerves. Modifying the afferent input makes possible to change discharge of vagal efferents affecting gastrointestinal functions in process known as neuromodulation (NM). Lately it has been used in the treatment of pain and hyperactive neurogenic bladder in urology. MC induced NM may therefore provide a concurrent to pharmacology tool, in treatment of gastrointestinal disorders. The aim of this study was to investigate the effects of long term neuromodulation procedure with use of MC on gastric motility, secretion and weight control in conscious rats. Experiments were performed on 30 Wistar male rats (250-350 g) divided in two groups: sham operated and microsurgically implanted with MC on left vagal nerve below diaphragm. Following stimulation parameters were used: frequency of 0.5-30 Hz, amplitude of 0.55 V, impulse duration of 10 ms in monophasic fashion. In both groups food intake and body weight were measured through the period of 2 weeks after recovery period. Then gastric fistula was implanted in gastric antrum and fasted gastric motility recorded with use of PowerLab system (Australia). Gastric emptying and secretion were also tested with use of phenol red and automatic titration methods. On the daily basis glucose level with standard test and leptin after MC implantation were measured. Recording of vagal activity in fasted rats showed burst of action potentials about 5 +/- 2.5 in period of 5000 sec, each burst with spike frequency up to 35 Hz. Food (5 ml of Intralipid--intragastrically) almost doubled amount of bursts to 12 +/- 5 in period of 5000 sec with increase in frequency at spike up to 50 Hz. MC induced vagal activity showed continuous spike activity similar to fed pattern. MC induced NM decreases daily food intake by 6% (33.6 +/- 4.8 vs control 35.5 +/- 4.8 g, p < 0.01). Body weight gain in rats before MC implantation decreased by 20% within 2 weeks after recovery (34.8 +/- 9.08 vs control 23.56 +/- 4.15 g). Fasting control glucose level also decreased of 5.5% (93.15 +/- 9.3 vs control 98.5 +/- 11.2 mg%, p < 0.05). Frequency of gastric contractions did not change significantly in MC versus control but amplitude of contractions increased of about 66.7% (2.0 +/- 0.8 vs 1.17 +/- 0.52) at the dominant frequency 0.08 Hz range and about 71.5% (1.17 +/- 0.35 vs 0.68 +/- 0.47, p < 0.05) at the frequency 0.12 Hz. in FFT analysis PowerLab (chart v = 4.01). BAO decreased by 29.25% without H+ concentration changes (0.2 +/- 0.14 vs 0.14 +/- 0.12 mmol/30 min, p < 0.05) but MAO did not change in MC rats (0.37 +/- 0.25 vs 0.42 +/- 0.28 mmol/30 min, p 0.05). Gastric emptying of isotonic solution increased by 10% (90.46 +/- 5.34 vs 80.39 +/- 9.95) percent of marker passing to duodenum/5 min, p < 0.0001). Our results suggest that MC induced NM affect brain-gut axis via influencing metabolic and gastric function and decreases body weight.

Animals↗
PubMed2001

The role of vagal efferents in regulation of gastric emptying and motility in rats.

UNLABELLED: Nonpharmacologic regulation of gastrointestinal motility may become competitive to actually applied methods in the nearest future. The Aim of this study was to evaluate effect of vagal stimulation on gastric motility and emptying. Experiments were performed on 30 male Wistar rats in vivo. Electrodes (120 um O Cr/Mo Microfil Industries) were placed on right vagal trunk below diaphragm without affecting its integrity. The fistula was implanted in gastric antrum. Stimulation parameters were: 0.3 V; 0.5 Hz, impulse duration--10 msec, time stimulation--5 min. Gastric pressure (balloon, Synectics pressure transducer, Sweden) and gastric emptying (red phenol method) were measured subsequently during and between stimulations. RESULTS: Stimulation significantly decreased amplitude of gastric contractions about 14% (52.7 +/- +/- 24.5 vs control 66.8 +/- 15.0; p < 0.05) and increased liquid gastric emptying from isotonic solution about 10% (87.35 +/- 4.75 vs control 75.31 +/- 11.24; p < 0.001), hypertonic liquid about 15% (49.05 +/- 12.16 vs control 34.1 +/- 13.68; p < 0.001) and hypotonic liquid about 7% (83.05 +/- 8.8 vs control 76.29 +/- 11.88). The frequency of gastric contractions did not change significantly in Fast Fourier Analysis of the period of stimulations and in control group. CCK concentrations were not significantly different between stimulated and control group (0.3 +/- 0.08 vs control 0.27 +/- 0.06 pmol/L). L-NAME infusion abolished completely acceleration of gastric emptying of isotonic solution (50.38 +/- 12.66 vc control 87.82 +/- 5.49; p < 0.05), hypertonic solution (32.17 +/- 15.09 vs control 51.65 +/- 10.74; p < 0.05) and hypotonic solution (60.42 +/- 12.05 vs control 82.67 +/- 8.06; p < 0.05) during electrical stimulation. DISCUSSION: In this experiment efferent stimulation of abdominal vagal nerve release neuromediators from afferent and efferent fibers. The main regulator seems to be nitric oxide. These results indicate the effective vagal nerve stimulation affects gastric motility and emptying. It is likely that observed effects reflect integrated response with activating vago-vagal reflexes and neurohumoral factors.

Animals↗