Colocalization pattern of cocaine- and amphetamine-regulated transcript peptide and parvalbumin immunoreactivity in the hippocampus proper of the chinchilla.

This study set out to investigate, for the first time, the distribution and colocalization pattern of cocaine-and amphetamine-regulated transcript (CART) and one of the calcium binding- -proteins: parvalbumin (PV) in the chinchilla's hippocampus proper (HP). HP, consisting of Ammon's horn (CA) and the dentate gyrus (DG), is an important component of the limbic system, involved in learning and memory processes. CA showed a higher immunoreactivity of CART (-IR) compared to DG. CART-IR neurons were mainly observed in the molecular layer of DG and in the pyramidal layer of CA. CART-IR fibers were present in the granular layer; in the hilus numerous mossy fibers were detected, while in the molecular layer CART-IR fibers were not found. In all CA fields (CA1-CA3), CART-IR fibers were only present in the lacuno- sum-molecular layer. Immunofluorescence with double- labeling showed that only CART-IR cells stained positive for PV, whereas in CART-IR fibers there was no PV-positive reaction. Our research supplements missing knowledge about the distribution and colocalization pattern of CART with PV in the chinchilla's hippocampus, and also provides a better understanding of the similarities and differences among individuals of the same species and also with other mammals.

The influence of bilberry fruit on memory and the expression of parvalbumin in the rat hippocampus.

Therefore, the aim of the present study was to evaluate the possible effect of bilberry fruit (Vaccinium myrtillus L.) supplement in a daily diet on the cognitive behaviour of the rats and the expression of paravalbumin (PV) in populations of hippocampal neurons. It has been postulated that the antioxidants present in bilberry fruit may act as neuroprotective factors playing also a significant role as memory enhancements. Forty Wistar rats with a similar average body weight (460 ± 0.4 g) were divided into four groups (n=10 per group). The control group received standard feed (210 g/week), whereas animals of experimental groups received standard feed supplemented with bilberry (per os) at consumed doses of 2 g (group I), 5 g (group II), and 10 g/kg b.w./ /day (group III). After three months of feeding with bilberry, the modified elevated plus-maze test (mEPM) was performed. After 32 weeks of feeding, brains were collected and PV-immunoreactive (ir) neurons were immunohistochemically visualized. In the modified elevated plus-maze test, transfer latency examined 2 h and 24 h after the acquisition session was significantly shorter (p⟨0.05) in the group II in comparison with the control group. In CA1 and CA2/CA3 hippocampal fields as well as dentate gyrus of all experimental groups, a significant (p⟨0.05) decrease in number of PV-ir neurons were found. In relation to the control group, the mean subpopulation of PV-ir neurons found in groups II and III were significantly reduced. The subpopulations of PV-ir neurons found in DG of all experimental groups were significantly reduced in comparison to the control. In conclusion the in the present paper we demonstrated a relationship between the diet rich in a bilberry fruit and process of memory as well as numbers of calcium- binding protein-expressing hippocampal neurons. Our results may be source of basic knowledge for further research aiming at neuroprotective role of the bilberry fruit.

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.

Distribution and immunohistochemical characteristics of cocaine- and amphetamineregulated transcript-positive nerve elements in the pelvic ganglia of the female pig.

Cocaine- and amphetamine-regulated transcript (CART) peptides are widely expressed not only in the brain but also in numerous endocrine/neuroendocrine cells as well as in neurons of the peripheral nervous system. The present study investigated the distribution patterns of CART-like immunoreactivity in the pelvic plexus (PP) of the female pig. The co-expression of CART with principal neurotransmitter markers: choline acetyltransferase (ChAT), tyrosine hydroxylase (TH), serotonin (5-HT) or biologically active neuropeptides: pituitary adenylate cyclase-activating polypeptide (PACAP), substance P (SP), calbindin was analyzed using double immunohistochemical stainings. Amongst neurons immunopositive to Hu C/D panneuronal marker as many as 4.1 ± 1.2% in right and 4.4 ± 1.6% in left pelvic ganglia were found to express CART. The vast majority of CART-IR ganglionic neurons were predominantly small in size and were evenly scattered throughout particular ganglia. Immunoreactivity to CART was also detected in numerous nerve terminals (which frequently formed pericellular formations around CART-negative perikarya) as well as in numerous nerve fibres within nerve branches interconnecting the unilateral pelvic ganglia. Immunohistochemistry revealed that virtually all CART-IR neurons were cholinergic in nature and CART-IR basket-like formations frequently encircled TH-positive/CART-negative perikarya. None of CART-IR ganglionic neurons showed immunoreactivity to SP, PACAP, 5-HT or calbindin. CART-IR nerve fibres ran in a close vicinity to serotonin-containing cells or faintly labelled SP-expressing neurons. On the other hand, PACAP-IR, SP-IR (but not 5-HT-positive) nerve terminals were found to run in close proximity to CART-IR neurons. Our results indicate that: 1) CART present in PP may influence the activity of pelvic ganglionic neurons/SIF cells, 2) PP should be considered as a potential source of CART-like supply to pelvic viscera and 3) functional interactions between CART and SP or PACAP are possible at the periphery.

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.