The expression of ß3-adrenoceptor and muscarinic type 3 receptor immuno-reactivity in the major pelvic ganglion of the rat.

Bladder afferent outflow, linked to sensation, plays a critical role in bladder pathology: abnormal outflow results in altered sensation, leading to increased voiding frequency, urge and often incontinence. ß3-adrenoceptor agonists have been suggested to be beneficial in treating these symptoms. However, the absence of a significant sympathetic innervation of the detrusor and only a modest relaxation of bladder muscle by ß3 agonists has questioned the therapeutic site of action of ß3 agonists in the bladder. The present study was done to explore the possibility that ß3-adrenoceptors might be located in the pelvic plexus. Using the rat, where the pelvic plexus is located primarily within a single ganglion, the major pelvic ganglion (MPG), immuno-histochemical approaches were used to identify structures expressing ß3-adrenoceptor immuno-reactivity (ß3AR-IR). The only structures found to express ß3AR-IR were small-diameter tyrosine hydroxylase and vesicular mono-amine transporter immuno-reactive (TH-IR and vmat-IR) neurones. These neurones, found in clusters or singly on the periphery of the ganglion, or dispersed in smaller clumps throughout the MPG, are similar to the small intensely fluorescent (SIF) cells described previously. Not all small cells expressed ß3AR-IR. A population of the small cells were also immuno-reactive to the type 3 muscarinic receptor (M3R-IR) and the P2X3 purinergic receptor (P2X3-IR). Clumps of small cells were associated with calcitonin gene-related peptide immuno-reactive (CGRP-IR) nerve fibres (putative sensory fibres) and a small number were contacted by putative cholinergic nerves expressing immuno-reactivity to vesicular acetylcholine transporter (vacht-IR). These observations are consistent with the idea that small cells are interneurons and one of the components making up complex neural circuits within the MPG. The precise physiological role of these neural elements in the MPG is unknown. However, as one therapeutic action of ß3-adrenoceptor agonists is to modulate sensation, it is possible that these neural circuits may be involved in the regulation of afferent outflow and sensation.

The protective effect of vitamin E on locus coeruleus in early model of Parkinson's disease in rat: immunoreactivity evidence.

BACKGROUND: Free radical formation and oxidative stress might play an important role in the pathogenesis of Parkinson's disease (PD). In vitro data indicate that neuromelanin (NM) pigment is formed the excess cytosolic catecholamine that is not accumulated into synaptic vesicles via the vesicular monoamine transporter 2 (VMAT2). We designed this study to investigate the neuroprotective effects of vitamin E in the early model of PD. METHODS: Male rats (n = 40) with unbiased rotational behavior were randomly divided into five groups: sham operated group (SH, n = 8), vehicle-treated SH group (SH + V, n = 8), vitamin E-treated SH group (SH + E, n = 8), vehicle-treated lesion group (L + V, n = 8) and vitamin E-treated lesion group (L + E, n = 8). Unilateral intrastriatal 6-hydroxydopamine (12.5 microl) lesioned rats were treated intramuscularly with alpha-tocopherol acid succinate (24 I.U/kg, intramuscular [i.m.]) 1 h before surgery and three times per week for 2 month post-surgery. To evaluate the vitamin E pretreatment efficacy, tyrosine hydroxylase (TH) immunoreactivity and immunostaining intensity (ISI) for monoamine transporter 2 were used. RESULTS: TH immunohistochemical analyses showed a reduction of 20 percent in locus coeruleus (LC) cell number of vitamin E pretreated lesioned group but the cell number dropped to 60 percent in the lesioned group. The ISI of the cells was measured for VMAT2 in LC. Lesioned groups: 1) had the lowest VMAT2 ISI of all neurons; 2) There was an inverse relationship between VMAT2 ISI and NM pigment in the locus and 3) Neurons with the highest VMAT2 ISI also had high TH ISI. CONCLUSION: The data support the hypothesis that repeated i.m. administration of vitamin E exerts a protective effect on the LC neurons in the early model of PD.

Synaptic contact between melanopsin-containing retinal ganglion cells and rod bipolar cells.

PURPOSE: Evidence indicates that the melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) receive input from rods and cones, which are thought to modulate the irradiance detecting system driving entrainment of the circadian system and pupillomotor control. This study was performed to identify retinal cells that have synaptic contact with ipRGCs. METHODS: Immunohistochemistry and high-power confocal microscopy were used to generate stacks of digital images of sections stained with antibodies against melanopsin, protein kinase C (PKCalpha), tyrosine hydroxylase (TH), presynaptic terminal markers (C-terminal binding protein 2 [CtBP2], vesicular monoamine transporter 2 [VMAT2] and postsynaptic marker (glutamate receptor subunit 4 [GluR4]). Results were analyzed in a computer-based three-dimensional reconstruction program for cellular contacts. RESULTS: Markers and melanopsin rod bipolar processes were found to have axosomatic and axodendritic contact with melanopsin-containing RGCs. Typically, three to four contacts were found on the soma of the melanopsin-containing RGCs, together with contacts on proximal dendrites. Contacts visualized by only CtBP2 immunoreactivity could also be demonstrated on melanopsin cell bodies and processes representing contacts with other types of bipolar cells. At the border of the inner plexiform layer (IPL) and inner nuclear layer (INL), where melanopsin processes stratify, contacts between melanopsin and TH or VMAT2 immunoreactivity processes were observed. CONCLUSIONS: Through confocal microscopy and computer-based three-dimensional analyses, this study demonstrates that melanopsin-containing RGCs have synaptic contact with PKC/CtBP2-containing rod bipolar cells and TH/VMAT2-immunoreactive amacrine cells through axodendritic and axosomatic contact, supporting electrophysiological observations that rods and cones signal to the melanopsin-containing intrinsically photosensitive RGCs.

Chromogranin A in gastric neuroendocrine tumours: an immunohistochemical and biochemical study with region-specific antibodies.

The aim of the present study was to investigate ECLomas and enterochromaffin-like (ECL) cell hyperplasia in gastric human mucosa regarding the immunohistochemical expression of chromogranin A (CgA) epitopes and to measure the same CgA epitopes in plasma samples. Eight gastric biopsies from ECLomas, seven of type I and one of type III, and biopsies from one patient showing only ECL cell hyperplasia were included in the study. Our results revealed a varying expression of region-specific CgA epitopes in the ECLomas regarding both the frequency of immunoreactive cells and intensity of immunoreactivity. CgA284-301 (pancreastatin) was not revealed in any neoplasm, whereas CgA361-372 (catestatin) was expressed in all ECLomas. However, the number of immunoreactive cells to vesicular monoamino transporter 2 (VMAT 2) or the commercial monoclonal CgA (CgA250-284) antibodies were generally higher. The plasma concentrations of the region-specific CgA radioimmunoassays differed considerably, with highest concentrations of CgA1-17 and CgA116-130 epitopes and the lowest with the CgA17-37, CgA63-76, CgA238-247 and CgA441-424 epitopes. No relationship was found between tissue expression and plasma concentration of CgA epitopes. In conclusion, this study shows that VMAT 2 and the commercial CgA antibodies seem more useful for histopathological diagnosis of ECLomas than the antibodies to the other CgA regions.