AB1582 Sigma-AldrichAnti-Choline Acetyltransferase Antibody

Cardiac sympathetic denervation is found in various cardiac pathologies; however, its relationship with myocardial injury has not been thoroughly investigated.Twenty-four rats were assigned to the normal control group (NC), sympathectomy control group (SC), and a sympathectomy plus mecobalamin group (SM). Sympathectomy was induced by injection of 6-OHDA, after which, the destruction and distribution of sympathetic and vagal nerve in the left ventricle (LV) myocardial tissue were determined by immunofluorescence and ELISA. Heart rate variability (HRV), ECG and echocardiography, and assays for myocardial enzymes in serum before and after sympathectomy were examined. Morphologic changes in the LV by HE staining and transmission electron microscope were used to estimate levels of myocardial injury and concentrations of inflammatory cytokines were used to reflect the inflammatory reaction.Injection of 6-OHDA decreased NE (933.1 ± 179 ng/L for SC vs. 3418.1± 443.6 ng/L for NC, P less than 0.01) and increased NGF (479.4± 56.5 ng/mL for SC vs. 315.85 ± 28.6 ng/mL for NC, P less than 0.01) concentrations. TH expression was reduced, while ChAT expression showed no change. Sympathectomy caused decreased HRV and abnormal ECG and echocardiography results, and histopathologic examinations showed myocardial injury and increased collagen deposition as well as inflammatory cell infiltration in the cardiac tissue of rats in the SC and SM groups. However, all pathologic changes in the SM group were less severe compared to those in the SC group.Chemical sympathectomy with administration of 6-OHDA caused dysregulation of the cardiac autonomic nervous system and myocardial injuries. Mecobalamin alleviated inflammatory and myocardial damage by protecting myocardial sympathetic nerves.

The basal forebrain (BF) comprises morphologically and functionally heterogeneous cell populations, including cholinergic and non-cholinergic corticopetal neurons that are implicated in sleep-wake modulation, learning, memory and attention. Several studies suggest that glutamate may be among inputs affecting cholinergic corticopetal neurons but such inputs have not been demonstrated unequivocally. We examined glutamatergic axon terminals in the sublenticular substantia innominata in rats using double-immunolabeling for vesicular glutamate transporters (Vglut1 and Vglut2) and choline acetyltransferase (ChAT) at the electron microscopic level. In a total surface area of 30,000 microm(2), we classified the pre- and postsynaptic elements of 813 synaptic boutons. Vglut1 and Vglut2 boutons synapsed with cholinergic dendrites, and occasionally Vglut2 axon terminals also synapsed with cholinergic cell bodies. Vglut1 terminals formed synapses with unlabeled dendrites and spines with equal frequency, while Vglut2 boutons were mainly in synaptic contact with unlabeled dendritic shafts and occasionally with unlabeled spines. In general, Vglut1 boutons contacted more distal dendritic compartments than Vglut2 boutons. About 21% of all synaptic boutons (n=347) detected in tissue that was stained for Vglut1 and ChAT were positive for Vglut1, and 14% of the Vglut1 synapses were made on cholinergic profiles. From separate cases stained for Vglut2 and ChAT, 35% of all synaptic boutons (n=466) were positive for Vglut2, and 23% of the Vglut2 synapses were made on cholinergic profiles. On average, Vglut1 boutons were significantly smaller than Vglut2 synaptic boutons. The Vglut2 boutons that synapsed cholinergic profiles tended to be larger than the Vglut2 boutons that contacted unlabeled, non-cholinergic postsynaptic profiles. The presence of two different subtypes of Vgluts, the size differences of the Vglut synaptic boutons, and their preference for different postsynaptic targets suggest that the action of glutamate on BF neurons is complex and may arise from multiple afferent sources.

Calbindin-D28k (CB) and calretinin (CR) are calcium binding proteins present in distinct sets of neurons; they act as buffers regulating the concentration of intracellular calcium. CB and CR immunohistochemistry was studied in the brainstem of anuran and urodele amphibians in combination with other markers (choline acetyltransferase, tyrosine hydroxylase, and nitric oxide synthase), which served to clarify the localization and signature of many cell groups. CR labeled the retinorecipient layers of the optic tectum, and CB and CR labeled distinct tectal cell populations. The two proteins were largely complementary in the torus semicircularis and marked auditory and lateral line sensory regions, depending on the species. CB and CR in the mesencephalic and isthmic tegmentum specified the boundaries of basal and medial longitudinal bands. In the cerebellum, CB labeled Purkinje cells in all species, whereas CR was mainly found in fibers and labeled Purkinje cells only in Rana. In the parabrachial region, CB and CR allowed the distinction of the laterodorsal tegmental nucleus, isthmic nucleus, locus coeruleus, and rostral octavolateral nuclei. The distribution of CB- and CR-immunoreactive cells in the reticular formation and central gray was consistent with the current models of brainstem segmentation in amphibians. CR was found in the auditory fibers and nuclei in Rana and in mechanosensory lateral line fibers in Xenopus and urodeles, whereas CB mainly labeled vestibular fibers and nuclei in all species. These results highlight the anatomical complexity of the amphibian brainstem and help in an understanding of its regional organization that is not cytoarchitectonically evident.

Panic disorder is a severe anxiety disorder characterized by susceptibility to induction of panic attacks by subthreshold interoceptive stimuli such as 0.5 M sodium lactate infusions. Although studied for four decades, the mechanism of lactate sensitivity in panic disorder has not been understood. The dorsomedial hypothalamus/perifornical region (DMH/PeF) coordinates rapid mobilization of behavioral, autonomic, respiratory and endocrine responses to stress, and rats with disrupted GABA inhibition in the DMH/PeF exhibit panic-like responses to lactate, similar to panic disorder patients. Utilizing a variety of anatomical and pharmacological methods, we provide evidence that lactate, via osmosensitive periventricular pathways, activates neurons in the compromised DMH/PeF, which relays this signal to forebrain limbic structures such as the bed nucleus of the stria terminalis to mediate anxiety responses, and specific brainstem sympathetic and parasympathetic pathways to mediate the respiratory and cardiovascular components of the panic-like response. Acutely restoring local GABAergic tone in the DMH/PeF blocked lactate-induced panic-like responses. Autonomic panic-like responses appear to be a result of DMH/PeF-mediated mobilization of sympathetic responses (verified with atenolol) and resetting of the parasympathetically mediated baroreflex. Based on our findings, DMH/PeF efferent targets such as the C1 adrenergic neurons, paraventricular hypothalamus, and the central amygdala are implicated in sympathetic mobilization; the nucleus of the solitary tract is implicated in baroreflex resetting; and the parabrachial nucleus is implicated in respiratory responses. These results elucidate neural circuits underlying lactate-induced panic-like responses and the involvement of both sympathetic and parasympathetic systems.

Acetylcholine (ACh) is well established as a neurotransmitter and/or neuromodulator in various organs. Previously, it has been shown by Ogura (J Neurophysiol 87:2643-2649, 2002) that in both physiological and immunohistochemical studies the muscarinic acetylcholine (ACh) receptor is present in taste receptor cells. However, it has not been determined if ACh is released locally from taste receptor cells and/or surrounding nerve fibers. In this study we investigated the sites of ACh release in mouse taste tissue using the antisera against vesicular ACh transporter (VAChT), a key element of ACh-containing vesicles. Our data show that VAChT-immunoreactivity is present in many taste receptor cells, including cells expressing the transient receptor potential channel M5 (TRPM5). In taste cells, VAChT-immunoreactivity was colocalized with the immunoreactivity to choline-acetyltransferase (ChAT), which synthesizes ACh. Additionally, enhanced green fluorescent protein (eGFP) was detected in the taste cells of BAC-transgenic mice, in which eGFP was placed under the control of endogenous ChAT transcriptional regulatory elements (ChAT(BAC)-eGFP mice). Furthermore, many ChAT-immunolabeled taste cells also reacted to an antibody against the vesicle-associated membrane protein synaptobrevin-2. These data suggest that ACh-containing vesicles are present in taste receptor cells and ACh release from taste cells may play a role in autocrine and/or paracrine cell-to-cell communication. In addition, certain nerve fibers surrounding or within taste buds were immunoreactive for the VAChT antibody. Some of these fibers were also immunolabeled with antibody against calcitonin gene-related peptide (CGRP), a marker for trigeminal peptidergic fibers. Thus, functions of taste receptor cells could be modulated by trigeminal fibers via ACh release as well.

Prevertebral sympathetic ganglia contain a unique population of final motor neurons receiving convergent synaptic inputs not only from spinal preganglionic neurons, but also from peripheral intestinofugal neurons projecting from the gut. We used quantitative confocal and ultrastructural immunohistochemistry to determine how this increased synaptic convergence is accommodated by sympathetic final motor neurons in the celiac ganglion of guinea pigs. Terminals of intestinofugal neurons were identified by their immunoreactivity to vasoactive intestinal peptide. Stereologic analyses were based on transects and point counts at confocal and ultrastructural levels. The relative amount of dendritic neuropil in the medial regions of the ganglion was approximately 2.5 times greater than in the lateral regions of the ganglion, consistent with the 2 to 3 times difference in average dendritic field size of neurons in these regions. The total numbers of boutons and synaptic profiles showed significant positive correlations with the relative amount of neuropil in a region. However, the overall density of synaptic boutons was twice as high in the medial region of the ganglion compared with the lateral regions. Because the relative density of preganglionic synapses was similar in each region, this difference was due to the selective projection of intestinofugal inputs to neurons in the medial celiac ganglion, where they provided 45% of synaptic contacts. These results show that, compared with vasoconstrictor neurons, sympathetic neurons regulating gastrointestinal activity support a higher number of convergent inputs in two ways: in addition to having larger dendritic fields, they also have a twofold higher density of synapses.

Neurons in prevertebral sympathetic ganglia receive convergent synaptic inputs from peripheral enteric neurons in addition to inputs from spinal preganglionic neurons. Although all inputs are functionally cholinergic, inputs from these two sources have distinctive neurochemical and functional profiles. We used multiple-labeling immunofluorescence, quantitative confocal microscopy, ultrastructural immunocytochemistry, and intracellular electrophysiologic recordings to examine whether populations of inputs to the guinea pig coeliac ganglion express different levels of synaptic proteins that could influence synaptic strength. Boutons of enteric intestinofugal inputs, identified by immunoreactivity to vasoactive intestinal peptide, showed considerable heterogeneity in their immunoreactivity to synaptosome-associated protein of 25 kDa (SNAP-25), synapsin, synaptophysin, choline acetyltransferase, and vesicular acetylcholine transporter. Mean levels of immunoreactivity to these proteins were significantly lower in terminals of intestinofugal inputs compared with terminals of spinal preganglionic inputs. Nevertheless, many boutons with undetectable levels of SNAP-25 immunoreactivity formed morphologically normal synapses with target neurons. Treatment with botulinum neurotoxin type A (20-50 nM for 2 hours in vitro) generated significant cleavage of SNAP-25 and produced similar dose- and time-dependent inhibitions of synaptic transmission from all classes of inputs, regardless of their mean level of SNAP-25 expression. The simplest interpretation of these results is that only synaptic boutons with detectable levels of SNAP-25 immunoreactivity contribute significantly to fast cholinergic transmission. Consequently, the low synaptic strength of intestinofugal inputs to final motor neurons in sympathetic pathways may be due in part to the low proportion of their boutons that express SNAP-25 and other synaptic proteins.

We investigated the muscular structure and innervation of the gastroduodenal junction in the guinea pig. In the gastroduodenal junction, the innermost layer of the circular muscle contained numerous nerve fibers and terminals. Since this nerve network continued onto the deep muscular plexus (DMP) of the duodenum, we surmised that the numerous nerve fibers in the gastroduodenal junction were specialized DMP in the most proximal part of the duodenum. The innermost layer containing many nerve fibers was about 1,000 microm in length and 100 microm in thickness in the proximal duodenum. This layer contained numerous connective tissue fibers composed of collagen and elastic fibers. Five to 30 smooth muscle cells lay in contact with each other and were surrounded by fine connective tissue. The nerve fibers in the proximal duodenum contained nerve terminals immunoreactive for choline acetyltransferase, dynorphin, enkephalin, galanin, gastrin-releasing peptide, nitric oxide synthase, substance P, and vasoactive intestinal polypeptide. Adrenergic fibers which contained tyrosine hydroxylase immunoreactivity were rare in the proximal duodenum. In the innermost layer of the proximal duodenum, there were numerous c-Kit immunopositive cells that were in contact with nerve terminals. This study allowed us to clarify the specific architecture of the most proximal portion of the duodenum. The functional significance of the proximal duodenum in relation to the electrical connection and neural cooperation of the musculature between the antrum and the duodenum is also discussed.

We examined the effect of fibroblast growth factor (FGF)-9 on primary cultures of rat basal forebrain cholinergic neurons (BFCN) obtained at embryonic day 17. FGF-9 enhanced survival of AChE-positive neurons, increased their mean soma size, and up-regulated their choline acetyltransferase (ChAT) activity. The ChAT-promoting effect of FGF-9 was approximately as potent as that of nerve growth factor (NGF) and was greater than those of basic fibroblast growth factor (bFGF), ciliary neurotrophic factor (CNTF), or glia-derived neurotrophic factor (GDNF). Simultaneous addition of FGF-9 and NGF induced extremely high ChAT levels, suggesting that FGF-9 and NGF may enhance cholinergic properties in BFCN via different pathways that can act synergistically. In immunocytochemical and in situ hybridization studies in cultured cells and also in sections of adult rat brain, BFCN showed cytoplasmic immunostaining for FGF-9 and expressed FGF-9 messenger RNA; thus, we concluded that FGF-9 acts on BFCN in an autocrine and/or paracrine manner. Although effective delivery of exogenous FGF-9 into the central nervous system remains a problem to be solved, FGF-9 may be a promising candidate for therapeutic trials in Alzheimer disease.

We have characterised sympathetic neurons projecting to a range of cutaneous and striated muscle vascular targets in the pinna of the rabbit ear by examining neurotransmitter-related enzymes and peptides in perivascular axons and in somata identified by retrograde axonal tracing. Fast Blue was injected into one of seven sites in each pinna (n = 21 pinnae). The soma cross-sectional area and immunoreactivity (IR) for tyrosine hydroxylase (TH) and neuropeptide Y (NPY) were determined for each of 2,041 retrogradely labelled neurons in the ipsilateral superior cervical ganglion (SCG) or stellate ganglion (StG). Larger neurons in the SCG with TH-IR but not NPY-IR projected predominantly to veins along the medial edge of the pinna. Larger neurons in the StG with TH-IR but not NPY-IR projected predominantly to arteries and veins in the tip and lateral edge of the pinna. Smaller neurons in the SCG with IR to both TH and NPY projected predominantly to arteries in the striated muscles at the base of the ear. The smallest retrogradely labelled neurons in the SCG or StG lacked TH-IR but contained NPY-IR and projected almost exclusively to arterial vessels in the lateral muscle at the base of the ear. Thus, somata of sympathetic neurons projecting to cutaneous versus striated muscle vessels or to different regions of the cutaneous bed could be distinguished by a combination of location, size, and immunohistochemical profile. Consequently, regulation of blood flow within the rabbit ear is likely to involve coordination between neuronal pathways containing neurochemically and morphologically distinct populations of sympathetic neurons.