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33.4??4.7?%, AXO vs. double arrows /em ), FB+/CB?/LENK+ ( em long arrows /em ) It has been found that under physiological conditions FB+/CB+ neurons constituted approximately 35?% of the whole FB+ cellular populace. It should be stressed that these cells were also neurochemically heterogeneous (Table?2 and Figs.?1 and ?and2).2). For example, many of FB+/CB+ cells co-expressed TH (33.4??4.7?%) Oligomycin A either NPY (25.1??3.8?%) or SOM (11.1??1.3?%), while a few of them co-expressed VIP (1.5??1.0?%; Table?2 and Figs.?1, 2aCh, and 3aCd). None of the FB+/CB-positive perikarya were found to be immunopositive to NOS, LENK, SP, VAChT, and GAL (Table?2 and Figs.?1 and ?and3eCl).3eCl). In axotomized animals, although the total quantity of the FB+/CB+ cells did not change, a strong reduction was observed among FB+/CB+/TH+ (16.8??3.5 vs. 33.4??4.7?%, AXO vs. control, respectively; em P /em ??0.001), FB+/CB+/NPY+ (1.4??0.4 vs. 25.1??3.8?%, AXO vs. control, respectively; em P /em ??0.001), and FB+/CB+/SOM+ (3.4??0.1 vs. 11.1??1.3?%, AXO vs. control, respectively; em P /em ??0.05) neurons (Table?2 and Figs.?1 and ?and2a2aCl). Conversation The pig pattern of axotomy-induced changes in the chemical coding of IMG neurons supplying descending colon The present study demonstrates changes in the chemical coding of the colon-projecting neurons located in the porcine IMG following axotomy of the nervi colici caudales. These changes include a reduction in the number of neurons expressing TH, NPY, and SOM and an increase in the number of neurons immunoreactive to LENK. Although the number of CB+ neurons was comparable in both the control and axotomized animals, there were significant discrepancies concerning the neurochemical features of this neuronal subset prior and after the injury. Thus, we have observed a strong downregulation of TH, NPY, and SOM expression in FB+/CB+ neurons. Calbindin-D28K plays a major role in calcium homeostasis in neurons CD163 and other cell types acting as a fast Ca2+ buffering system in the cytoplasm (Schwaller et al. 2002; Schwaller 2009). This way, calbindin may safeguard neurons against large fluctuations in free intracellular Ca2+ and prevent cell death. Since axotomy causes a massive influx of calcium into the lesioned neurons (Wolf et al. 2001), an increase in calbindin expression in IMG should be expected. However, it seems not to be the case as the number of CB-expressing neurons was comparable in both Oligomycin A the control and axotomized animals. One of the possible explanations for such phenomenon in IMG may be that the other calcium-binding proteins like parvalbumin or calretinin were engaged. Such mechanism, for example, i.e., ability to upregulate parvalbumin after axotomy, paralleled by a smaller increase of intracellular calcium was reported in oculomotor neurons of mice (Obal et al. 2006). The pig pattern of axotomy-induced changes in the IMG vs. other ganglia and/or species It is widely accepted that one of the most relevant changes in the neuronal phenotype following axotomy is the downregulation of physiological neurotransmitter production and the increase in the expression of neuropeptides which are essential for survival and/or regeneration (Hyatt-Sachs et al. 1996; Zigmond and Sun 1997; Zigmond 2000). Our data show that this colon-projecting neurons located in the porcine IMG react in a similar manner; however, this manner differs in some details from that explained in other ganglia and/or species. TH The considerable decrease in TH expression in the FB+ populace in porcine IMG after caudal colonic nerve axotomy is usually well in line Oligomycin A with earlier data obtained from the porcine IMG after partial or total uterus extirpation (Wasowicz 2003a, b, c). The same phenomenon was also observed in the rat superior cervical ganglia (SCG), where the decreased expression of the catecholamine-producing enzymes has also been noticed after axotomy (Klimaschewski et al. 1996; Shadiack et al. 2001; Sun and Zigmond 1996). NPY In addition to the decreased catecholamine production, the axotomy-induced reduction in the number of NPY perikarya was also observed in the porcine IMG, which is consistent with the data obtained from the rat SCG explained earlier by Bachoo et al. (1992) and Sun and Zigmond (1996). A decrease of NPY expression should not be amazing since NPY-expressing neurons form a large populace.