Authors:Piotr Burliński, Sławomir Gonkowski and Jarosław Całka
The aim of the present study was to establish the effect of intravesical administration of resiniferatoxin (RTX) and tetrodotoxin (TTX) on the chemical coding of paracervical ganglion (PCG) neurons supplying the urinary bladder in the pig. In order to identify the PCG neurons innervating the bladder, retrograde tracer Fast Blue was injected into the bladder wall prior to intravesical RTX or TTX administration. Consequent application of immunocytochemical methods revealed that in the control group 76.82% of Fast Blue positive PCG neurons contain nitric oxide synthetase (nNOS), and 66.92% contain acetylcholine transferase (ChAT). Intravesical infusion of RTX resulted in a reduction of the nNOS-IR neurons to 57.74% and ChAT-IR to 57.05%. Alternative administration of TTX induced an increase of nNOS-IR neurons up to 79.29% and a reduction of the ChAT-IR population down to 3.73% of the Fast Blue positive PCG cells. Our data show that both neurotoxins affect the chemical coding of PCG cells supplying the porcine urinary bladder, but the effects of their action are different. Moreover, these results shed light on the possible involvement of NO-ergic and cholinergic neurons in the mechanisms of therapeutic action exerted by RTX and TTX in curing the overactive bladder disorder.
Authors:Joanna Wojtkiewicz, Sławomir Gonkowski, Marek Bladowski and Mariusz Majewski
The aim of this study was to investigate the distribution and the number of cocaine- and amphetamine-regulated transcript-like immunoreactive (CART-LI) neurons and the co-localisation of CART with substance P (SP), somatostatin (SOM), nitric oxide synthase (NOS) and vasoactive intestinal polypeptide (VIP) within the enteric nervous system (ENS) in the porcine small intestine. Accordingly, the myenteric plexus (MP), outer submucous plexus (OSP) and inner submucous plexus (ISP) of the small intestine (duodenum, jejunum and ileum) were studied by double-labelling immunofluorescence technique. CART-LI neurons were observed in all gut fragments and all types of intramural plexuses studied and amounted from 0.2 ± 0.1% in the ISP of ileum to 22.4 ± 2.4% in the MP of this segment. The co-localisation of CART and NOS or/and VIP was observed depending on the segment of the gut and the complexity of the intramural plexus. On the other hand, during this study the co-localisation of CART and SOM or/and SP was not observed. The present study, for the first time, presents a detailed description of the CART distribution pattern and co-localisation with other neuromodulators within the ENS of the porcine small intestine.
Authors:Sławomir Gonkowski, Piotr Burliński, Cezary Skobowiat, Mariusz Majewski and Jarosław Całka
This study reports on changes caused by chemically driven inflammation and axotomy in galanin-like immunoreactive (GAL-LI) nerve structures in the porcine descending colon. The distribution pattern of GAL-LI structures was studied using the immunofluorescence technique in the circular muscle layer, the myenteric (MP), outer submucous (OSP) and inner submucous plexuses (ISP), and also in the mucosal layer. Under physiological conditions GAL-LI perikarya were shown to constitute 3.68 ± 0.32%, 7.02 ± 0.93% and 10.99 ± 0.71% in MP, OSP and ISP, respectively. Both colitis and axotomy caused an increase in GAL-like immunoreactivity, which was different in particular parts of the bowel segment studied. The numbers of GAL-LI perikarya increased to 14.16 ± 0.49%, 16.78 ± 1.09% and 37.46 ± 1.18% during colitis and 7.92 ± 0.72%, 10.44 ± 0.71% and 16.20 ± 0.96% after axotomy in MP, OSP and ISP, respectively. Both these processes caused an increase in the number of GAL-LI nerve fibres in the circular muscle and mucosal layers as well as the appearance of a population of GAL-LI cells in the mucosa.
Authors:Slawomir Gonkowski, Piotr Burliński, Cezary Skobowiat, Mariusz Majewski, Marcin Arciszewski, Piotr Radziszewski and Jarosław Całka
The aim of the present study was to investigate the number of cocaine- and amphetamine-regulated transcript-like immunoreactive (CART-LI) nerve structures in the large intestine of juvenile pigs. The distribution pattern of CART-LI structures was studied by immunohistochemistry in the circular muscle layer, myenteric (MP), outer submucous (OSP) and inner submucous plexus (ISP) as well as in the mucosal layer of six regions of the large bowel: caecum, centripetal and centrifugal turns of the proximal colon, transverse colon, descending colon and rectum. CART-LI neural structures were observed in all gut fragments studied. CART-LI nerve fibres were numerous within the circular muscle layer and in the MP of all the regions studied, while they were moderate or few in number in other layers of the intestinal wall. The numbers of CART-LI neurons within the MP amounted to 2.02% in the caecum to 7.92% in the rectum, within the OSP from 2.73% in the centrifugal turns of the proximal colon to 5.70% in the rectum, and within the ISP from 2.23% in the transverse colon to 5.32% in the centrifugal turns of the proximal colon. The present study reports for the first time a detailed description of the CART distribution pattern within the enteric nervous system (ENS) of the porcine large intestine.
Authors:Liliana Rytel, Anna Snarska, Slawomir Gonkowski, Joanna Wojtkiewicz, Ottó Szenci and Przemyslaw Sobiech
Neuropeptide Y (NPY) is a neuronal active substance taking part in the regulation of gastrointestinal (GI) tract activity. This study used retrograde neuronal tracing and immunofluorescence methods to analyse NPY-positive neurons located in superior cervical ganglion and supplying the cervical oesophagus in the pig. The presence of NPY was observed in 30% of all neurons supplying the part of oesophagus studied. Probably the number of Fast Blue (FB) positive cells depends on the area of the wall injected with FB and the fragment of oesophagus studied. Therefore, the obtained results indicate that the described peptide is an important factor in the extrinsic innervation of this part of the GI tract.
Due to its difficult diagnosis and complicated treatment, inflammatory bowel disease (IBD) in dogs is a challenge for the veterinarian. Several aspects connected with pathological changes during IBD still remain unknown. Since one of these aspects is the participation of intestinal innervation in the evolution of the disease, the aim of this study was to demonstrate changes in the number and distribution of intramucosal colonic nerve fibres immunoreactive to substance P (SP) arising as the disease progresses. SP is one of the most important neuronal factors in intestinal innervation which, among other tasks, takes part in the conduction of pain stimuli. Using routine immunofluorescence technique, the density of nerve fibres containing SP was evaluated within mucosal biopsy specimens collected from the descending colon of healthy dogs and animals suffering from IBD of varying severity. The results of the study indicate that during severe IBD the number of nerve fibres containing SP located in the colonic mucosal layer increases in comparison to control animals. The number of SP-positive intramucosal nerves amounted to 10.99 ± 2.11 nerves per observation field in healthy dogs, 14.62 ± 2.86 in dogs with mild IBD, 14.80 ± 0.91 in dogs with moderate IBD and 19.03 ± 6.11 in animals with severe IBD. The observed changes were directly proportional to the intensity of the disease process. These observations may suggest a role of this neuronal substance in pathological processes occurring during IBD. Although the exact mechanism of the observed changes has not been completely explained, the results obtained in this investigation may contribute to improving the diagnosis and treatment of this disease, as well as the staging of canine IBD in veterinary practice.