Inflammation- and axotomy-induced changes in galanin-like immunoreactive (GAL-LI) nerve structures in the porcine descending colon

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.