Immunohistochemical localization of calcium binding proteins and some neurotransmitters in myenteric plexus of goat stomach.

To understand the neurochemical properties of the gastric myenteric plexus of ruminants, the expression patterns of calbindin D-28k (CB), calretinin (CR), substance P (SP) and calcitonin gene-related peptide (CGRP) were explored in the Korean native goat. In gastric myenteric plexus, CB and SP immunoreactivity were observed in round- or oval-shaped neurons. CR and CGRP immunoreactivity were detected only in the nerve fibers. This immunohistochemical localization of CB, CR, CGRP and SP in the myenteric plexus of the goat stomach exhibited species-specific patterns. These findings suggest that these substances may be directly or indirectly related to the gastric functions of the goat stomach.

Age-related changes in calretinin-immunoreactive periglomerular cells in the rat main olfactory bulb.

The changes of calretinin (CR)-immunoreactive periglomerular cells in the glomerular layer of the main olfactory bulb (MOB) were investigated in rats differing ages from postnatal month 1 (PM 1) to PM 24. The number of cresyl violet-positive periglomerular cells was similar between PM 1 and PM 12, but they decreased slightly in the PM 24 group. The size of CR-immunoreactive periglomerular cells in the glomerular layer increased with age, while their numbers did not change significantly in the PM 6-PM 24 groups. In the PM 24 group, numbers of CR-positive periglomerular cell bodies and their processes decreased, while the size of CR-positive cell bodies in the glomeruli was larger than that of the previous groups. These results suggest that CR-immunoreactive periglomerular cells in the rat MOB are well-developed in the PM 6 group, and that periglomerular cells in the PM 24 group show poor CR-immunoreactivity compared to those in the PM 6 group.

Mineralocorticoid and glucocorticoid receptor expressions in astrocytes and microglia in the gerbil hippocampal CA1 region after ischemic insult.

In the present study, we observed expression and changes of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the gerbil hippocampal CA1 region, but not in the CA2/3 region, after 5 min of transient forebrain ischemia. In blood, corticosterone levels were increased biphasically at 30 min and 12 h after ischemia/reperfusion, and thereafter its levels were decreased. In the sham-operated group, MR and GR immunoreactivities were weakly detected in the CA1 region. By 3 days after ischemia, MR and GR were not significantly altered in the CA1 region: at 12 h after ischemia, GR was expressed in a few neurons in the CA1 region, whereas MR was not expressed in any neurons after ischemic insult. From 4 days after ischemia, MR and GR immunoreactivities were detected in astrocytes and microglia in the CA1 region, and at 7 days after ischemia, MR and GR immunoreactivities peaked in the hippocampal CA1 region. At this time, 55% of astrocytes and 30% of microglia showed MR immunoreactivity, and 20% of astrocytes and 40% of microglia showed GR immunoreactivity. Western blot analyses showed that the pattern of changes in MR and GR protein levels was similar to the immunohistochemical changes observed after transient forebrain ischemia. From 4 days after ischemia, MR and GR protein levels were increased time-dependently after ischemia. In conclusion, enhanced MR and GR expressions in astrocytes and microglia were detected in the hippocampal CA1 region 4-7 days after ischemia/reperfusion. At this time, GR immunoreactivity was abundant in microglia, whereas MR immunoreactivity was prominent in astrocytes. The specific distribution of corticosteroid receptors in the astrocytes and microglia may be associated with the differences of MR and GR functions against ischemic damage.

Transient ischemia-induced changes of neurofilament 200 kDa immunoreactivity and protein content in the main olfactory bulb in gerbils.

This study was carried out to investigate alterations of neurofilament 200 kDa (NF-200) and its polyphosphorylation form (RT97) immunoreactivity and protein content in the main olfactory bulb (MOB) after 5 min of transient forebrain ischemia in gerbils. In the sham-operated group, weak NF-200 immunoreactivity was detectable in a few somata of mitral cells, which projected weak NF-200-immunoreactive processes to the external plexiform layer (EPL). At 1-5 days after ischemia, strong NF-200 and RT97 immunoreactivity was shown by the mitral cell processes; however, somata of mitral cells did not show NF-200 immunoreactivity. At this time point, strong NF-200-immunoreactive mitral cell processes ran to the EPL and glomerular layer (GL). Thereafter, NF-200 and RT97 immunoreactivity was decreased up to 30 days after ischemia. In the 15 days post-ischemic group, the distribution pattern of NF-200 and RT97 immunoreactivity was slightly lower than that in the 1-5 days post-ischemic groups. In the 30 days post-ischemic group, moderate NF-200 and RT97 immunoreactivity was found in the mitral cells processes, but the immunoreactivity in the EPL and GL nearly disappeared. A Western blot study showed a pattern of NF-200 and RT97 expression at all post-ischemic time points similar to that of immunohistochemistry after ischemia. This result indicates that NF-200 and RT97 accumulates in injured mitral cell processes a few days after transient ischemia, which suggests that the axonal transport in the MOB may be disturbed during this period after transient ischemia.

Very delayed neuronal loss occurs in the glomerular layer of the main olfactory bulb following transient ischemia in gerbils.

Olfactory dysfunction could happen following various insults such as ischemic-hypoxic state. Neurons of the main olfactory bulb (MOB) are resistant to ischemic damage. In the present study, we investigated the ischemia-related changes of neurons and glial cells in the glomerular layer (GL) of the gerbil MOB after transient ischemia. The number of NeuN-immunoreactive neurons became to decrease from 10 days after ischemic insult. Fifteen days after ischemic insult, astrocytes and microglia were increased in number. By 60 days after ischemia, NeuN-immunoreactive neurons were significantly decreased by 42% per glomerulus. At this time period, astrocytes and microglia were pronouncedly increased. This result indicates that neuronal loss must be much delayed in the GL following transient ischemia.

Expressional changes of neuropeptide Y and cholecystokinin in the arcuate and paraventricular nuclei after capsaicin administration.

Despite its toxicity, a great deal of attention has been paid to the anorexic effect of capsaicin in the treatment of obesity-related neurotransmitters/neuromodulators. To determine if capsaicin has any effects on the orexigenic or anorexigenic peptides, the neuropeptide Y (NPY)- and cholecystokinin (CCK)-immunoreactivities were demonstrated in the rat hypothalamus by immunohistochemistry after capsaicin administration. There was a significantly lower concentration of NPY immunopositive cells in the arcuate and paraventricular nuclei of the capsaicin treated rats. In contrast, the CCK expressions level was higher in the paraventricular nucleus of the capsaicin treated rats than in the control rats. These results suggest that capsaicin influence neuropeptides such as orexigenic NPY and anorexigenic CCK related to control food intake.

Changes in the expression of calbindin D-28k in the gerbil hippocampus following seizure.

Previous studies have reported that calbindin D-28k (CB), a calcium-binding protein, containing neurons in the hippocampus play an important role in hippocampal excitability in epilepsy, because CB modulates the free calcium ion during seizure. Hence, in the present study, we investigated changes of CB expression in the hippocampus and its association in the Mongolian gerbil to identify roles of CB in epileptogenesis. CB immunoreactivity in the hippocampus was significantly lower in the pre-seizure group of seizure sensitive (SS) gerbils as compared with those seen in the seizure resistant (SR) gerbils. The distribution of CB immunoreactivity in the hippocampus showed significant difference after seizure on-set in SS gerbils. CB immunoreactivity in the hippocampal CA1, CA2 areas, and subiculum was lowest at 3h after seizure on-set; thereafter, the immunoreactivity became to increase to 12h after seizure on-set. Mossy fibers, Schaffer collaterals and dentate granule cells showed the highest CB immunoreactivity at 3h after seizure on-set; thereafter, the immunoreactivity became to decrease. In the case of the intrinsic and output connections of the hippocampus, a rapid decrease of CB serves an inhibitory function, which regulates the seizure activity and output signals from the hippocampus.

Left costocervical vein malformation with anomalous ramification of aortic arch in a dog.

This report describes coexistence of anomalous branches of the aortic arch and the costocervical vein malformation in a German shepherd dog. The first branch of the aortic arch was a bicarotid trunk that divided into the left and right common carotid arteries. The next branch to leave the aortic arch was a common trunk for the right and left subclavian arteries, a bisubclavian trunk, which was immediately bifurcated. The right subclavian artery passed over the esophagus forming a deep groove, so-called incomplete vascular ring on the dorsal wall of the esophagus. Although the esophagus was constricted by the right subclavian artery dorsally and by the trachea ventrally, no clinical symptoms of esophageal obstruction and dysphagia were observed. The left costocervical vein coursed caudoventrally, passed over the aortic arch, and entered the left ventricle. This vessel was much smaller than the right costocervical vein and was partially occluded at its origin.

Elevation of Na+-K+ ATPase immunoreactivity in GABAergic neurons in gerbil CA1 region following transient forebrain ischemia.

In a previous study, we suggested that GABAergic neurons might be resistant to ischemic insult, because of the maintenance of the GABA shunt, which is one of the ATP synthetic pathways in neurons. In the present study, we identified Na(+)-K(+) ATPase immunoreactivity in the gerbil hippocampus in order to determine whether changes in Na(+)-K(+) ATPase immunoreactivity correlate with GABA shunt following ischemic insult. At 12 h after ischemia-reperfusion, Na(+)-K(+) ATPase immunoreactivity accumulated in some neurons in the CA1 region. However, the protein content of Na(+)-K(+) ATPase was not altered. Interestingly, the density of Na(+)-K(+) ATPase immunoreactivity in neurons and the protein content in the CA1 region was intensified in the 24 h post-ischemic group. As a result of double immunofluorescence study, Na(+)-K(+) ATPase immunoreactive neurons were identified with GABAergic neurons. Therefore, our findings suggest that the increase of Na(+)-K(+) ATPase in GABAergic neurons may be able to explain the resistance of these cells to ischemic insult, and support our previous hypothesis that GABA may play an important role as a metabolite in the survival of GABAergic neurons after ischemic insult.