Yu-Qiang Ding

Localisation of neurokinin 3 (NK3) receptor immunoreactivity in the rat gastrointestinal tract.

Abstract.The localisation of the neurokinin 3 receptor (NK3r) in the rat gastrointestinal tract has been studied by using a polyclonal antiserum against the C-terminal portion (amino acids 388–452) of the rat NK3r. In the oesophagus, immunoreactivity for the NK3r was found on smooth muscle cells of the muscularis mucosae. NK3r immunoreactivity was not present on muscle cells of other regions. Nerve cell bodies immunoreactive for NK3r were seen in the myenteric and submucous plexuses of the small and large intestine, but not in the stomach or oesophagus. Immunoreactivity was largely confined to nerve cell surfaces. The reaction product was on the cell soma and initial parts of axons. Reactivity was not seen on nerve terminals. Immunoreactive nerve cells had Dogiel Type II morphology. Patterns of co-localisation of NK3r and immunoreactivity for other markers were examined in the ileum, to provide a basis from which to deduce the functional identity of NK3r-immunoreactive nerve cells. Most of the NK3r-immunoreactive nerve cells were also immunoreactive for the calcium-binding proteins, calretinin and calbindin, and all were immunoreactive for the NK1 receptor (NK1r). Nerve cells that were immunoreactive for nitric oxide synthase were not immunoreactive for either NK3r or NK1r. The projections of the calbindin and calretinin neurons were determined by nerve lesion studies. Their morphology, projections to the mucosa and other ganglia and immunoreactivity for the calcium-binding proteins suggest that the NK3r-immunoreactive neurons are intrinsic sensory neurons.

Immunocytochemical localization of μ-opioid receptor in primary afferent neurons containing substance P or calcitonin gene-related peptide. A light and electron microscope study in the rat

Co-expression of mu-opioid receptor-like immunoreactivity (MOR-LI) with substance P (SP)- or calcitonin gene-related (CGRP)-LI was observed in rat trigeminal and dorsal root ganglion neurons. In particular, MOR-LI was found in axon terminals with SP- or CGRP-LI in laminae I and II of the medullary and spinal dorsal horns. MOR may be implicated in modulation of release of SP and CGRP from primary sensory afferents.

Direct projections from the lumbosacral spinal cord to Barrington's nucleus in the rat: A special reference to micturition reflex

In the present study, direct projections from the lumbosacral cord to Barringtons nucleus in the rat were investigated by using retrograde and anterograde tracing techniques. After injection of cholera toxin B subunit (CTb) into Barringtons nucleus, a number of moderately CTb‐labeled neurons were observed in the lumbosacral cord, with a slight ipsilateral dominance; most were located in the spinal parasympathetic and dorsal commissural nuclei of the lumbosacral cord. In addition, some retrogradely labeled neurons were found in the periaqueductal gray (PAG). These findings were confirmed by an anterograde labeling experiment. After biotinylated dextran amine (BDA) was injected into the lumbosacral cord, dense BDA‐labeled axon terminals were found in Barringtons nucleus as well as in the PAG. Injection of BDA into the PAG resulted in many BDA‐labeled terminals in Barringtons nucleus. The present results provided clear evidence for a direct projection from the spinal parasympathetic and dorsal commissural nuclei to Barringtons nucleus that could subserve conveying bladder‐filling information from the lumbosacral cord to Barringtons nucleus in the micturition reflex of the rat. J. Comp. Neurol. 389:149–160, 1997.

Strong Expression of Interleukin-1 Receptor Type I in the Rat Carotid Body

One of the unsolved key questions in neuroimmunomodulation is how peripheral immune signals are transmitted to the brain. It has been reported that the vagus might play a role in this regard. The underlying mechanism for this immune system-to-brain communication route is related to the binding of cytokines, such as interleukin (IL)-1β originating from activated immune cells, to their receptors in glomus cells of the vagal paraganglia. The existence of IL-1 receptor type I (IL-1RI) in vagal paraganglia has been proved. On the basis of these studies, a hypothesis is raised that the carotid body, as the largest paraganglion, might play a similar role to that of its abdominal partner. In this study we examined the distribution of IL-1RI in the carotid body by immunohistochemistry (IHC) and Western blotting techniques. The IHC results showed that almost all glomus cells in the carotid body displayed strong IL-1RI immunoreactivity. The IL-1RI-immunoreactive products were localized in the cytoplasm, nucleus, and cell membrane of the glomus cells. The Western blotting results also confirmed the existence of IL-1RI in both membranous and cytoplasmic elements of the carotid body. These results imply that the carotid body not only serves as a chemoreceptor for modulation of cardiorespiratory performance, as traditionally recognized, but also acts as a cytokine chemorereceptor for sensing immune signals.

Substance P receptor (NK1)-immunoreactive neurons projecting to the periaqueductal gray: distribution in the spinal trigeminal nucleus and the spinal cord of the rat

Substance P receptor (SPR)-immunoreactive neurons projecting to the periaqueductal gray (PAG) were examined in the rat spinal trigeminal nucleus and spinal cord by a retrograde tracing method combined with immunofluorescence histochemistry. After injection of Fluoro-gold (FG) into the PAG, SPR-immunoreactive neurons labeled with FG were observed mainly in the lateral spinal nucleus and lamina I of the medullary and spinal dorsal horns and additionally in laminae V and X of the spinal cord.

Mesencephalic dopaminergic neurons expressing neuromedin K receptor (NK3): a double immunocytochemical study in the rat

By using a double immunocytochemical method we examined the distribution of dopaminergic neurons expressing neuromedin K receptor (NKR; NK3) in the rat brain. The distribution of NKR-like immunoreactive (-LI) neurons completely overlapped that of tyrosine hydroxylase (TH)-LI neurons in the retrorubral field (A8), substantia nigra (A9), ventral tegmental area and nucleus raphe linealis (A10). Completely or partially overlapping distributions of NKR- and TH-LI neurons were found in certain regions of the hypothalamus (A11-A15) and olfactory bulb (A16). Neurons showing both NKR- and TH-like immunoreactivities, however, were only found in A8-A10: All of the NKR-LI neurons displayed TH-like immunoreactivity, and about 71-86% of the TH-LI neurons expressed NKR-like immunoreactivity. The present results provided morphological evidence for physiological modulation of dopaminergic neurons by tachykinins through NKR in A8-A10.

The distribution and origin of axon terminals with NADPH diaphorase activity in the nucleus of the solitary tract of the rat

The distribution and origin of axon terminals containing nitric oxide synthase (NOS) were examined in the nucleus of the solitary tract (NST) of the rat by NADPH diaphorase histochemistry combined with nodose ganglionectomy. Axon terminals with NADPH diaphorase activity were densely distributed in the middle and caudal part of the NST. After removal of the nodose ganglion (NG), most of the axon terminals with NADPH activity in the NST were eliminated on the ipsilateral side. These results indicated that most of the axon terminals with NADPH diaphorase in the NST derive from the primary afferent neurons in the NG, and that NOS may be richly contained in the central terminals of NG neurons to produce nitric oxide as a transmitter.

Neurokinin B receptor (NK3)-containing neurons in the paraventricular and supraoptic nuclei of the rat hypothalamus synthesize vasopressin and express Fos following intravenous injection of hypertonic saline

Subnuclear localization of neurokinin B receptor (NK3) in the paraventricular and supraoptic nuclei of the hypothalamus was immunohistochemically investigated in the rat. In the paraventricular hypothalamic nucleus, intense neurokinin B receptor-like immunoreactivity was found in the posterior magnocellular part, moderate to weak neurokinin B receptor-like immunoreactivity was seen in the other parts. In the supraoptic nucleus, intense neurokinin B receptor-like immunoreactivity was distributed in its principal part, and a few neurons with neurokinin B receptor-like immunoreactivity were found in the retrochiasmatic part. Co-localization of neurokinin B receptor-like immunoreactivity with vasopressin-like immunoreactivity was examined through serial adjacent sections. Neurons with both neurokinin B receptor-like immunoreactivity and vasopressin-like immunoreactivity were primarily found in the supraoptic nucleus and posterior magnocellular part of the pavaventricular nucleus. A small number of neurons with neurokinin B receptor-like immunoreactivity and vasopressin-like immunoreactivity were also seen in the circular nucleus and the region surrounding blood vessel in the anterior hypothalamus. Many neurokinin B receptor-containing neurons in the paraventricular and supraoptic nuclei, as well as in circular nucleus and the region surrounding the blood vessel, expressed Fos-like immunoreactivity after intravenous injection of hypertonic saline. The present study demonstrated that a large proportion of neurokinin B receptor-like immunoreactive neurons in the paraventricular hypothalamic and supraoptic nuclei contained vasopressin-like immunoreactivity, and expressed Fos-like immunoreactivity after intravenous administration of hypertonic saline. The results suggest that neurokinin B receptor in the two nuclei may be involved in modulation of the release of vasopressin when the internal environment is disturbed.

Co-localization of μ-opioid receptor-like immunoreactivity with substance P-LI, calcitonin gene-related peptide-LI and nitric oxide synthase-LI in vagal and glossopharyngeal afferent neurons of the rat

Co-localization of mu-opioid receptor (MOR)-like immunoreactivity (-LI) with substance P (SP)-LI, calcitonin gene-related peptide (CGRP)-LI and nitric oxide synthase (NOS)-LI in the nodose, petrosal and jugular ganglia was examined in the rat by a double immunofluorescence histochemical method. About 0.6%, 41% and 95% of neurons with MOR-LI, respectively, in the nodose, petrosal and jugular ganglia showed SP-LI; about 2%, 51% and 66% of MOR-like immunoreactive neurons displayed CGRP-LI in the nodose, petrosal and jugular ganglia, respectively. In addition, about 59% of MOR-like immunoreactive neurons in the nodose ganglia displayed NOS-LI, whereas no NOS-LI was detected in the petrosal or jugular ganglion. These data provide evidence for co-localization of MOR-LI with SP-LI, CGRP-LI and NOS-LI in the vagal and glossopharyngeal afferent neurons, and suggest that MOR may regulate the release of SP, CGRP and nitric oxide from the visceral primary afferent terminals in the nucleus of the solitary tract of the rat.

The major pelvic ganglion is the main source of nitric oxide synthase-containing nerve fibers in penile erectile tissue of the rat

The possible implication of nitric oxide synthase (NOS) in penile erection was examined by utilizing NADPH histochemistry in the rat. NADPH histochemistry indicated that the major pelvic ganglion (MPG), a well-known origin of nerve fibers supplying the external genitalia, contained many NOS-positive neurons. On the other hand, NOS-positive nerve fibers in penile erectile tissue observed in the walls of both arteries and veins, as well as in intrinsic smooth muscles. The retrograde tracing study with Fluoro-Gold (FG) in combination with NADPH histochemistry revealed that almost all MPG neurons which were retrogradely labeled with FG injected into the penile crura were NOS-positive. Thus, the MPG was considered to be the main source of NOS-positive nerve fibers in penile erectile tissue.