Torsten Grunditz

Neuropeptide Y: Occurrence and distribution in dental pulps

Nerve fibers displaying neuropeptide Y (NPY) immunoreactivity were seen in the dental pulp of several mammals, including man. Generally, the NPY fibers were more numerous in the apical part than in the coronal part and were distributed around small blood vessels and as single fibers in the pulpal stroma. Sequential staining with antibodies against the enzyme dopamine-beta-hydroxylase (DBH), a marker for adrenergic neurons, and NPY showed that DBH and NPY were located in the same perivascular nerve fibers. Further, since chemical and surgical sympathectomy caused the disappearance of pulpal NPY fibers, it is conceivable that NPY fibers in the dental pulp are identical with adrenergic ones. There is thus a morphological basis for suggesting that NPY and noradrenaline cooperate in regulating pulpal blood flow.

Distribution and origin of nerve fibers in the rat temporomandibular joint capsule.

Abstract The distribution and origin of nerve fibers containing neuropeptides and NOS projecting to the temporomandibular joint capsule (TMJ) of the rat were studied by retrograde tracing in combination with immunocytochemistry. Numerous nerve fibers were seen in the TMJ as revealed by the neuronal marker protein gene product 9.5. Nerve fibers containing neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), pituitary adenylate cyclase activating peptide (PACAP), substance P (SP), calcitonin gene-related peptide (CGRP), and nitric oxide synthase (NOS) were seen in the synovial membrane, the joint capsule and entering the articular disc. Injection of the retrograde tracer True Blue (TB) into the TMJ resulted in the appearance of numerous labeled nerve cell bodies in the trigeminal and superior cervical ganglia, and moderate numbers in the nodose, the otic, the sphenopalatine, the stellate and the dorsal root ganglia at levels C2–C5. Most of the TB-labeled cell bodies in the superior cervical and stellate ganglia contained NPY. In the trigeminal ganglion, numerous TB labeled cell bodies contained CGRP and a minor population stored SP, a few cell bodies were seen to store NOS or PACAP. In the sphenopalatine and otic ganglia, TB labeled cell bodies contained NOS or VIP. In the nodose ganglion, labeled cell bodies contained CGRP; other labeled cell bodies harbored NOS. In the cervical dorsal root ganglia, the majority of the labeled cell bodies stored CGRP and smaller populations stored SP and PACAP. Thus, the innervation of the TMJ is complex and many different ganglia are involved.

Origin and peptide content of nerve fibers in the nasal mucosa of rats.

Injection of the retrograde neuronal tracer True blue into the anterior-lateral part of the nasal mucosa of rats labeled nerve cell bodies in the superior cervical ganglion, the sphenopalatine ganglion, the otic ganglion and the trigeminal ganglion on the ipsilateral side. In the superior cervical ganglion, the sphenopalatine ganglion and the trigeminal ganglion on the contralateral side, very few nerve cell bodies were labeled, indicating that these ganglia provide minor contributions only. The number of labeled cell bodies indicates that the superior cervical ganglion, the sphenopalatine ganglion and the trigeminal ganglion contribute most to the innervation of the nose, while the contribution from the otic ganglion is minor. Cell bodies in the superior cervical ganglion harbored noradrenaline (NA) or NA/neuropeptide Y (NPY); in the sphenopalatine ganglion vasoactive intestinal peptide (VIP) or VIP/NPY; in the otic ganglion VIP, VIP/NPY or VIP/substance P (SP) and in the trigeminal ganglion calcitonin gene-related peptide (CGRP) or CGRP/SP. The results from denervations and tracer experiments suggest that all NA-containing and the majority of NPY-containing fibers in the nasal mucosa are derived from the superior cervical ganglion (sympathetic nerve supply). VIP- and VIP/NPY-containing fibers originate from the sphenopalatine and otic ganglia (parasympathetic nerve supply). Nerve fibers containing CGRP and CGRP/SP emanate from the trigeminal ganglion (sensory nerve supply).

Is helodermin produced by medullary thyroid carcinoma cells and normal C-cells? Immunocytochemical evidence

Helodermin is a VIP/secretin-like 35-amino acid peptide originally isolated from the venom of the lizard Gila monster. Recently, helodermin-immunoreactive material was demonstrated in mammalian salivary glands, brain and gut. In the present study 8 human medullary thyroid carcinomas as well as 4 normal thyroid glands were examined immunocytochemically for the presence of helodermin using an antiserum raised against helodermin-(5-35) that does not cross-react with VIP or secretin. Cells displaying helodermin-like immunoreactivity were found in all tumours examined except one. On the whole the helodermin-immunoreactive cells had the same distribution as those storing calcitonin, suggesting coexistence of the two peptides in most of the tumour cells. Also normal human C-cells displayed helodermin immunoreactivity. The results suggest that a peptide chemically related to helodermin is a constituent of human medullary thyroid carcinoma cells as well as of normal C-cells.

Neuropeptide Y and vasoactive intestinal peptide coexist in rat thyroid nerve fibers emanating from the thyroid ganglion.

Neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) occur in nerve fibers around blood vessels and between follicles in the thyroid gland of the mouse and rat. VIP-immunoreactive fibers are numerous, while NPY-immunoreactive fibers are fewer. Most of the latter fibers contain noradrenaline (NA) as well as NPY, while a subpopulation was found to contain VIP instead of NA. We have determined the origins of rat thyroid nerve fibers containing NPY, VIP or NPY/VIP by investigating 3 conceivable sources, i.e. the superior cervical ganglion, the nodose ganglion and the thyroid ganglion. Chemical sympathectomy or removal of the superior cervical ganglion did not affect the frequency of VIP-immunoreactive fibers but eliminated most of the NPY-immunoreactive fibers as well as all NA-containing nerve fibers (recognized by antibodies to dopamine-beta-hydroxylase). The NPY-immunoreactive fibers that remained after sympathectomy occurred around blood vessels and between follicles and contained VIP. Cervical vagotomy (removal of the nodose ganglion including the adjacent vagus) did not overtly affect the frequency of NPY/VIP-, VIP-, or NPY/NA-containing fibers in the thyroid. In contrast, extirpation of the thyroid ganglion, which is situated immediately outside the thyroid capsule, greatly reduced the number of VIP- and NPY/VIP-containing fibers in the rat thyroid. On the whole, the results of radioimmunoassay of NPY and VIP agreed well with the immunocytochemical findings. High performance liquid chromatography confirmed the identity of NPY and VIP. The present findings suggest the existence in the rat thyroid of one NPY-containing nerve fiber population that harbours NA and emanates from the superior cervical ganglion; one NPY-containing fiber population that is non-adrenergic, harbours VIP and originates in the thyroid ganglion; and a second VIP-containing fiber population that is devoid of NPY and appears to derive from the thyroid ganglion.

Distribution and origin of the peripheral innervation of rat cervical esophagus

Several neurotransmitters, neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), galanin, enkephalin, calcitonin-gene related peptide (GGRP), substance P, as well as nitric oxide synthase (NOS), and the noradrenergic marker tyrosine-hydroxylase (TH) were localized by immunocytochemistry in the cervical esophagus of rat. Nerve fibers containing the neuropeptides, NOS, and TH were distributed in the myenteric plexus, around muscle bundles and small blood vessels. Injection of the retrograde tracer True Blue (TB) into the cervical esophagus resulted in the appearance of labeled nerve cell bodies in the superior cervical, the stellate, the nodose, the sphenopalatine, the dorsal root ganglia at levels C2−C7, and in local ganglia close to the thyroid. Most of the TB-labeled nerve cell bodies in the superior cervical ganglia contained NPY. In the stellate ganglion, a few labeled nerve cell bodies contained VIP whereas an additional few cell bodies stored NPY. In local ganglia, the majority of labeled cell bodies contained VIP. In the nodose ganglion and cervical dorsal root ganglia, the majority of the labeled nerve cell bodies stored CGRP. The results indicate that the cervical esophagus has a dense innervation with multiple neurotransmitters emanating from several ganglia. As judged by the pattern of nerve fiber distribution, they may regulate esophageal peristalsis and blood flow, some of them possibly in a cooperative manner.

Peptide-containing neurons projecting to the vocal cords of the rat: retrograde tracing and immunocytochemistry

The distribution and origin of neuropeptide Y-, vasoactive intestinal peptide- and calcitonin gene-related peptide-containing nerve fibers and adrenergic (dopamine-beta-hydroxylase-containing) fibers in the rat larynx were studied by retrograde tracing and selective denervations in combination with immunocytochemistry. An injection of the retrograde tracer True Blue to the right vocal cord resulted in the appearance of labelled nerve cell bodies in the ipsi- and contralateral superior cervical and stellate ganglia, the thyroid ganglia, the jugular-nodose ganglionic complexes, in the ipsilateral trigeminal and dorsal root ganglia at levels C2 and C3 and in local tracheal ganglia. Judging from the number of labelled nerve cell bodies, the jugular-nodose ganglionic complexes, dorsal root ganglia and superior cervical ganglia provide the greater part of the vocal cord innervation. Most of the True Blue-labelled nerve cell bodies in the superior cervical and stellate ganglia contained neuropeptide Y. In the thyroid ganglia the majority of labelled nerve cell bodies contained vasoactive intestinal peptide. In the jugular-nodose ganglionic complex and the dorsal root ganglia the majority of the labelled nerve cell bodies stored calcitonin gene-related peptide. Retrograde tracing and denervation studies revealed that all noradrenaline- and the majority of neuropeptide Y-containing nerve fibers emanate from the superior cervical and stellate ganglia. A minor population of neuropeptide Y-containing nerve fibers originate in local tracheal ganglia. The vasoactive intestinal peptide-containing nerve fibers originate in the thyroid ganglion and local tracheal ganglia, whereas calcitonin gene-related peptide-containing nerve fibres emanate from the dorsal root ganglia (C2-C3), the trigeminal ganglia and the jugular-nodose ganglia.

Sodium-Iodide Symporter Mediates Iodide Secretion in Rat Gastric Mucosa In Vitro

In vivo studies on rats have demonstrated that considerable amounts of iodide are transported from the bloodstream into the gastric lumen. The mechanisms for and functional significance of this transport are poorly understood. Active (driven by Na+/K+-ATPase) iodide transport into thyroid follicular cells is mediated by the sodium-iodide symporter (NIS), which is also abundantly expressed in gastric mucosa. We aimed to further investigate the iodide transport in gastric mucosa and the Possible role of NIS in this transport process. Iodide transport in rat gastric mucosa was studied in vitro in an Ussing chamber system using 125I as a marker. The system allows measurements in both directions over a mucosal specimen. A considerable transport of iodide (from the serosal to the mucosal side) was established across the gastric mucosa, whereas in the opposite direction (mucosa to serosa), iodide transport was negligible. Sodium Perchlorate (NaClO4), a competitive inhibitor of NIS, and ouabain, an inhibitor of the Na+/K+-ATPase, both attenuated gastric iodide transport from the serosal to the mucosal side. To investigate a possible neuroendocrine regulation of the iodide transport identified to occur from the serosal to the mucosal side of the stomach, thyroid-stimulating hormone (TSH), thyrotropin-releasing hormone (TRH), vasoactive intestinal peptide (VIP), histamine, or nitric oxide donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP) was added. None of these substances influenced the iodide transport. We conclude that iodide is actively transported into the gastric lumen and that this transport is at least partly mediated by NIS. Additional investigations are needed to understand the regulation and significance of this transport.

Cholecystokinins but not gastrin-17 release calcitonin from thyroid C-cells in the rat.

Subcutaneous injections of gastrin-17, cholecystokinin-39, cholecystokinin-8 (sulfated and non-sulfated forms), cholecystokinin-4 or pentagastrin induced hypocalcemia in rats. The hypocalcemia was associated with calcitonin release for pentagastrin and the cholecystokinins but not for gastrin-17, even at very high doses. Permanent hypergastrinemia, induced by surgical removal of the acid-producing part of the stomach (fundectomy) or by treatment with high doses of omeprazole, a blocker of acid secretion, was not accompanied by elevated plasma calcitonin. Long-lasting hypergastrinemia is known to cause hyperplasia of gastrin-sensitive endocrine cells in the rat stomach while hypogastrinemia does the reverse. In antrectomized rats, having low serum gastrin, and in fundectomized rats, having high serum gastrin, the serum calcitonin concentration, the thyroid calcitonin content and the number of C-cells remained as in sham-operated controls two months after the operations. We conclude that neither exogenous nor endogenous gastrin stimulates calcitonin secretion in the rat and that long-standing hypo- or hypergastrinemia is without effect on the number of thyroid C-cells. Our results, however, do not exclude the possibility that the cholecystokinins might act as calcitonin secretagogues in the rat although such a role remains to be established.

Regulatory Peptides in the Thyroid Gland

The mammalian thyroid gland harbours two different endocrine cell types: follicular and parafollicular (C) cells. The follicle cells are of entodermal origin and develop from the thyroglossus duct in the floor of the pharyngeal cavity(1,2). The C cells are thought to derive from the neuroectoderm(3). The C cell precursors migrate to form the ultimobranchial bodies which persist as separate organs throughout life, in submammalian vertebrates(4,5). In mammals the ultimobranchial bodies fuse with the thyroid anlage during the fetal development (6–8). The follicle cells synthesize and secrete triiodothyronine (T3) and tetraiodothyronine or thyroxine (T4), which control energy metabolism and are necessary for normal growth(9). The C cells synthesize, store and secrete calcitonin (CT), which is thought to he involved in the regulation of serum Ca by suppressing bone resorption(10,11).