Immunohistochemical study on the expression of biologically active substances in the endocrine pancreas of the European bison.

Previous morphological studies of mammalian pancreatic islets have been performed mainly in domestic and laboratory animals. Therefore, the present immunohistochemical investigation was conducted in a wild species, the European bison, using antibodies against glucagon-like peptide-1 (GLP1), glucagon, insulin and somatostatin. Morphological analyses revealed that the mean area of the endocrine pancreas constituted 2.1±0.1% of the whole area of the pancreas, while the mean area of a single pancreatic islet was 13301.5±686.5 µm2. Glucagon-immunoreac- tive cells accounted for 22.4±1.1% and occupied 19.4±0.4% of the average islet area. As many as 14.3±1.4% of pancreatic islet cells were shown to express GLP1, which constituted 12.6±0.8% of the mean area of the islet. Insulin expression was confirmed in 67.6±0.7% of pancreatic islet cells, which represented 62.3±4.9% of the mean total area of the pancreatic islet. As many as 8.5±1.3% of cells stained for somatostatin. The somatostatin-immunoreactive cell area was 4.9±0.3% of the mean pancreatic islet area. In summary, we have determined in detail for the first time the morphometry and islet composition of the European bison pancreas. The distri- bution patterns of immunoreactivities to the substances studied in the European bison show many similarities to those described in other ruminant species.

Effect of feeding with bilberry fruit on the expression pattern of αCaMKII in hippocampal neurons in normal and diabetic rats.

αCaMKII, widely occurring in the central nervous system, plays a significant role in cognitive processes. It is well known that diabetes is a risk factor that may trigger brain atrophy, cognitive dysfunction and finally lead to memory loss. Antioxidants richly present in bilberry fruits are believed to have significant effects on diabetes-related brain dysfunctions mainly due to their abilities to modulate neurotransmitter release that lead to reduction of the negative impact of free radicals on cognitive processes. The aim of the present research was to immunohistochemically investigate the expression patterns of αCaMKII in hippocampal neurons from non-diabetic, diabetic and diabetic rats fed with an extract of bilberry fruit. The obtained results show that in comparison to the control group, in diabetic rats hippocampal neurons immunoreactive (ir) to αCaMKII were swollen and the lengths of the neuronal fibres were reduced. Further study shows that in diabetic rats fed with bilberry fruit, αCaMKII-positive nerve fibres were significantly longer when compared to the groups of diabetic and control rats. Additionally, we observed statistically significant changes in the average larger diameter of αCaMKII-ir hippocampal neurons between groups of diabetic rats (with vs. without supplement of bilberry fruit). The results of the present work suggest that antioxidants present in bilberry fruits influence the morphology of and possibly exhibit beneficial and neuroprotective effects on hippocampal neurons during diabetes. It is likely that changes in the appearance of αCaMKII-expressed hippocampal neurons may reflect the diabetes-evoked rise in Ca2+ level in the cerebral nerve terminals. The present research extends our knowledge of preventive mechanisms for cognitive dysfunctions occurring in the brain during diabetes.

Pituitary adenylate cyclase-activating peptide-27 (PACAP-27) is co-stored with galanin, substance P and corticotropin releasing factor (CRF) in intrapancreatic ganglia of the sheep.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide existing in two variant forms (of either 27 or 38 residues), widely present in numerous organs and evoking multiple effects both in the central and peripheral nervous systems. The present study was undertaken to evaluate the distribution pattern of PACAP-27 expression in the ovine pancreas. Using double immunohistochemical stainings co-localizations of PACAP-27 with galanin, SP or CRF were studied in intrapancreatic neurons. In intrapancreatic ganglia, immunoreactivty to PACAP-27 was found in 87.6 ± 5.4% of PGP 9.5-positive intrapancreatic neurons but not in intraganglionic nerve fibres. Numerous PACAP-27-immunoreactive nerve terminals were also observed between pancreatic acini and around small arterioles. No immunoreactivity to PACAP-27 was found in the endocrine pancreas. In 42.9 ± 6.2% of PACAP-27-immunoreactive intrapancreatic neurons the expression of galanin was also found. Statistically lower subpopulation (12.4 ± 4.0%) of intrapancreatic neurons exhibited simultaneously the immunoreactivity to PACAP-27 and SP. The expression of CRF was detected in the relatively smallest group (3.2 ± 1.4%) of PACAP-27-positive intrapancreatic neurons. The present results suggest that in the ovine pancreas PACAP-27 may play an important role as mediator of pancreatic functions. In PACAP-related pancreatic activities, a modulatory role of galanin, SP and to a lower extend of CRF is also likely.

Immunocytochemical detection of calretinin in the claustrum and endopiriform nucleus of the chinchilla.

Calretinin (CR) as a buffer and sensor protein plays an important role in regulatory processes of Ca²âº and anty-apoptotic cellular protection. In the present study, immunohistochemical peroxidase-antiperoxidase (PAP) method was used in order to determine the numbers, morphology, morphometry and distribution pattern of CR in neurons of the chinchilla's claustrum (Cl) and endopiriform nucleus (EN). In Cl and EN the presence of several classes of neurons with different immunoreactivity to CR was found. In Cl, CR-immunoreactive (IR) neurons were predominantly found in close vicinity to insular border while CR-IR neurons were evenly scattered throughout EN. In general, immunoreaction to CR was observed in neuronal cytoplasm, nucleus and in fibres-like nerve extensions. Statistical analysis showed the differences between average large diameter as well as cross-sectional area of CR-IR neurons present in Cl and EN. It is suggested, that CR acting as a calcium binding protein may play a role in neuronal network. Further co-localization studies are necessary to fully elucidate neurophysiology and neuropathology of the chinchilla's Cl and EN neurons.