Distribution of galanin-immunoreactive nerve fibers in the rat nasal mucosa

Galanin-immunoreactive nerve fibers in the periodontal ligament during experimental tooth movement

Neuropeptides have been suggested to play a role in pain transmission during orthodontic tooth movement. We examined this hypothesis by examining the effect of orthodontic tooth movement on the expression of galanin (GAL)-immunoreactive (ir) nerve fibers in the periodontal ligament (PDL) of one mesial root (MR) and two distal roots (DRs) of the rat maxillary first molar. In control rats, GAL-ir fibers were very rare in the PDL. One day after the insertion of the elastic band, the number of GAL-ir fibers increased, becoming most numerous at 3 days. From 5 to 28 days, GAL-ir fibers tended to decrease. Electron microscopic observation showed that all of the GAL-ir fibers were unmyelinated. These findings suggest that GAL-containing nerve fibers in the PDL may play an important role in the response of the tissue to experimental tooth movement.

Localization and coexistence of calcium-binding proteins and neuropeptides in the vagal ganglia of the goat

This study was performed to investigate the neurochemical characteristics of the vagal ganglia of the goat by immunohistochemical methods using calbindin D-28k (CB), calretinin (CR). parvalbumin (PA), substance P (SP). calcitonin generelated peptide (CGRP) and galanin (GAL) antibodies. In the proximal vagal ganglia (jugular ganglia), CGRP- (57.1%), SP- (48.2%), GAL- (8.6%), PA- (8.7%), CB- (8.5%) and CR-like (5.3%) immunoreactive cells were observed. In the distal vagal ganglia (nodose ganglia), CGRP- (40.5%), SP- (30.20%), CB- (22.0%) and CR-like (18.10%) immunoreactive cells were present. The double immunohistochemical study showed, that in the proximal vagal ganglia, CGRP immunoreactivity was co-localized in SP- (84.8%), GAL-(100%), CB- (5.6%) and CR- (5.7%) immunoreactive cells: SP immunoreactivity was co-localized in the CGRP- (80.0%), GAL- (100%). CB- (5.3%) and CR- (5.6%) immunoreactive cells; GAL immunoreactivity coexisted in the CGRP- (4.4%) and SP- (19.8%) immunoreactive cells, but not in calcium-binding proteins (CBP)-immunoreactive cells; PA immunoreactivity was absent in the CGRP- and SP-immunoreactive cells; CB and CR immunoreactivities were seen in the CGRP-(0.8%) and SP-immunoreactive (0.9%) cells. On the other hand, in the distal vagal ganglia, CGRP immunoreactivity appeared in SP- (66.6%), CB- (1.0%) and CR- (1.2%) immunoreactive cells; SP immunoreactivities were observed in the CGRP- (44.1%), CB- (1.0%) and CR- (1.2%) immunoreactive cells; CB immunoreactivities were present in the CGRP- (0.5%) and SP- (0.8%) immunoreactive cells; CR immunoreactivities were contained in the CGRP- (0.5%) and SP- (0.8%) immunoreactive cells. These findings indicate that the goat is distinct from other mammalian species in the distribution and localization of neurochemical substances in the vagal ganglia. and suggest that these differences may be related to physiological characteristics, particular those of the ruminant digestive system.

Innervation of blood vessels in the vomeronasal complex of the rat

We have made an immunohistochemical study of the vomeronasal (VN) complex of 12-day-old rats to characterize the innervation of its blood vessels. The VN complex can be subdivided into rostral, middle and caudal segments, each one with a particular vascularization pattern. Several small vessels were associated with the rostral segment, whereas a large venous sinus ran along the middle and caudal segments. Immunostaining for alpha-smooth muscle actin demonstrated that the muscular sheath was asymmetric, with more cells layers in its lateral than in its medial walls. Nerves were demonstrated with antisera against protein gene product 9.5 (PGP), and against several molecules associated with specific classes of nerve fibers: the C-terminal peptide of neuropeptide Y (CPON), calcitonin gene-related peptide (CGRP), substance P (SP), galanin (GAL), vasoactive intestinal peptide (VIP) and neuronal nitric oxide synthase (NOS). The latter, was also studied with NADPH-diaphorase. Vascular associated fibers exhibited NOS-, CPON-, GAL-, CGRP-, SP- and VIP-immunoreactivity. Only the vessels of the rostral segment showed VIP-immunoreactive fibers. Each wall of the venous sinus exhibited different types of nerve fibers. CPON-, GAL-, CGRP- and SP-immunoreactive fibers concentrated in the medial wall, whereas NOS-immunoreactive ones concentrated in the lateral wall. This distribution of vascular fibers, plus the presence of sensory fibers exhibiting CGRP-, SP- and GAL-immunoreactivity within the pseudostratified epithelium of the VN tube, would be relevant to understand the operation of the pumping mechanism regulating influx and efflux from the VN tube.

Distribution and possible origin of galanin-like immunoreactive nerve fibers in the mammalian dental pulp

Human, dog, cat and rat dental pulps were investigated for the presence and distribution of galanin-like immunoreactive (-IR) nerve fibers, and the possible origin of pulpal galanin-IR nerve fibers in the rat was examined. Galanin-IR nerve fibers were present in the dental pulps of all species examined. Two types of galanin-IR nerve fibers were distinguished with regard to morphology; thin varicose nerve fibers and thick smooth-surfaced nerve fibers. Thin varicose galanin-IR nerve fibers were seen to run along the blood vessel in the human, dog and cat root pulp. In the coronal pulp, galanin-IR nerve fibers ran toward the odontoblastic layer but they did not form the subodontoblastic nerve plexus. In rat molar pulp, few galanin-IR nerve fibers were observed; the distribution of these nerve fibers was similar to those in human, dog and cat pulp. In contrast, many thick smooth-surfaced galanin-IR nerve fibers were observed near the blood vessels in incisor pulp of the rat; occasionally a few varicose galanin-IR nerve fibers were also observed. Transection of the inferior alveolar nerve or mandibular nerve caused complete disappearance of galanin-IR nerve fibers in rat dental pulp, while surgical sympathectomy of the superior cervical ganglion did not affect their distribution. The present results indicate that galanin-IR nerve fibers are present in the mammalian dental pulp, and that the intrapulpal galanin-IR nerve fibers in the rat originate from the trigeminal ganglion and are primary afferents.

Galanin immunoreactivity in autonomic innervation of the cat eye

In an immunohistochemical study, we find that galanin is much more widely distributed in the peripheral innervation of the cat eye than in other animals so far examined. Previous studies of rat and pig eyes have revealed sparse galanin-positive nerves that presumably originate in the trigeminal ganglion. In contrast, the cat has a rich supply of galanin-containing nerve fibers throughout the uvea. Galanin-positive varicose nerves concentrate densely in iris muscles and distribute more sparsely in the ciliary muscle. The ciliary processes have a plexus of galanin-positive nerves underlying the ciliary epithelium at their base and positive nerve fibers coursing within their stroma. The ciliary artery and its branch vessels in the uvea are invested with a dense plexus of galanin-positive nerves. All autonomic ganglia supplying the eye contain cells that express galanin. It is present in 97% of superior cervical ganglion cells, coexisting with both tyrosine hydroxylase and neuropeptide Y; in 80% of pterygopalatine ganglion cells, most of which also contain vasoactive intestinal peptide; and in approximately 25% of ciliary ganglion cells. After unilateral superior cervical ganglionectomy, galanin-positive nerves almost totally disappear from the iris muscles, demonstrating that they are predominantly of sympathetic origin. Galanin-positive nerves investing the ciliary artery and choroidal blood vessels are not detectably reduced by sympathectomy, indicating that perivascular parasympathetic nerves from the pterygopalatine ganglion also express galanin. Other galanin-containing nerves in the eye can originate from the trigeminal and ciliary ganglia. The prominence of galanin in the ocular autonomic innervation of the cat provides an opportunity to explore the physiological effects of this neuropeptide in the eye.

Somatostatin, galanin and peptide histidine isoleucine in the newborn and adult human trigeminal ganglion and spinal nucleus: immunohistochemistry, neuronal morphometry and colocalization with substance P

By means of indirect immunofluorescence the neuropeptides somatostatin, galanin and peptide histidine isoleucine were localized in cell bodies, nerve fibres and terminal-like elements in the ganglion and spinal nucleus of the human trigeminal nerve in perinatal and adult ages. No immunoreactivity to vasoactive intestinal polypeptide was observed. In the gasserian ganglion somatostatin-, galanin- and peptide histidine isoleucine-containing neurons and nerve fibres occurred frequently in pre- and full-term newborns, but were scarce to absent in adults. Somatostatin- and galanin-positive pericellular basket-like structures around non-immunoreactive perikarya were observed in newborn specimens. Immunoreactivity to somatostatin, galanin and peptide histidine isoleucine labelled nerve fibers and punctate and felt-like nerve terminals in the pars interpolaris and subnucleus caudalis of the spinal trigeminal nucleus, with immunostaining and distribution patterns characteristic for each peptide. In addition, somatostatin-containing neuronal cell bodies frequently were detected. At variance with those containing somatostatin, the number of galanin- and peptide histidine isoleucine-like immunoreactive elements were dramatically reduced in the adult tissue compared to the newborn one. Double immunostaining revealed that each of the three peptides partially colocalizes with substance P, the degree of coexistence being very low for somatostatin/substance P and high for galanin/substance P and peptide histidine isoleucine/substance P both in the gasserian ganglion and in the spinal nucleus. The results obtained suggest that somatostatin, galanin and peptide histidine isoleucine may play functional roles in primary sensory neurons and at the first synaptic level of the human trigeminal sensory system.

Coexistence of galanin and substance P in the mouse nasal mucosa, including the vomeronasal organ

Immunohistochemical fluorescent double labeling revealed the coexistence of galanin and substance P in nerve fibers in the mouse nasal mucosa. At the base of and in the epithelium, all galanin fibers also contained substance P, but around the blood vessels and glands, most of them did not. Since substance P fibers in the nasal mucosa originate from the trigeminal ganglion, these results suggest that galanin fibers in the submucosal region originate from ganglia other than the trigeminal.

Proportions of renal and splenic postganglionic sympathetic populations containing galanin and dopamine beta hydroxylase

Galanin is a 29-amino acid neuropeptide found in rat spinal cord, autonomic ganglia and gastrointestinal tract, as well as in other areas of the nervous system in rats and other species. As part of an overall objective to determine if peptides contribute to target-specific control of visceral function, this study was designed to determine the percentages of populations of renal and splenic postganglionic neurons that contain galanin, and to determine if these neurons were likely to be adrenergic. Retrogradely transported fluorescent dyes were placed on renal and splenic nerves in male Wistar rats anaesthetized with sodium pento-barbital. Four days post-operatively, rats were perfused transcardially with fixative, and T12-L1 thoracolumbar chain ganglia, splanchnic ganglia and the solar plexus were removed. Immunocytochemical methods were then used to determine the proportions of the retrogradely labelled renal and splenic neurons containing galanin-like immunoreactivity and dopamine beta hydroxylase-like immunoreactivity. In seven rats, 24 +/- 3% of 2838 renal neurons were found to contain galanin-like immunoreactivity; in six rats, 32 +/- 5% of 5102 splenic neurons were found to contain galanin-like immunoreactivity. These proportions of the two populations were not significantly different from one another. In three rats, 94 +/- 2% of 684 renal neurons were found to contain dopamine beta hydroxylase-like immunoreactivity, and 95 +/- 2% of 2597 splenic neurons in three rats also showed dopamine beta hydroxylase-like immunoreactivity. These experiments indicate that subpopulations of both renal and splenic postganglionic sympathetic neurons contain the neuropeptide galanin and that these neurons are likely to be adrenergic in function. These findings suggest a role for galanin in control of the kidney and the spleen by the sympathetic nervous system.

Autonomic and peptidergic innervation of human nasal mucosa

The localization and distribution of vasoactive intestinal polypeptide (VIP), peptide histidine methionine (PHM), the novel peptide helospectin, neuropeptide tyrosine (NPY) and its C-flanking peptide (C-PON), substance P and calcitonin gene-related peptide (CGRP) were studied in the middle and inferior turbinate of the human nose using sensitive immunocytochemical and radioimmunological methods. For light microscopy, double immunofluorescence and immunogold-silver staining methods were applied. Ultrastructural immunoelectronmicroscopy was performed using a pre-embedding method. In addition, semithin Epon resin sections were immunostained. The concentrations of VIP, NPY, CGRP, substance P and neurokinin A were measured using radioimmunological methods. A dense network of autonomic and peptidergic nerve fibers in the normal human nasal mucosa was demonstrated. Colocalization studies showed the coexistence of peptides with components of the autonomic nervous system. Scattered chromogranin A-, CGRP and bombesin-flanking peptide (BFP)-immunoreactive endocrine-like cells were detected within the lamina propria and in groups within exocrine ducts. Highest radioimmunoassay (RIA) tissue concentrations were detected for VIP, followed by NPY, substance P, CGRP and neurokinin A.

Fine structural aspects of secretion and extrinsic innervation in the olfactory mucosa

The mucus at the surface of the olfactory mucosa constitutes the milieu in which perireceptor events associated with olfactory transduction occur. In this review, the ultrastructure of olfactory mucus and of the secretory cells that synthesize and secrete olfactory mucus in the vertebrate olfactory mucosa is described. Bowman's glands are present in the olfactory mucosa of all vertebrates except fish. They consist of acini, which may contain mucous or serous cells or both, and ducts that traverse the olfactory epithelium to deliver secretions to the epithelial surface. Sustentacular cells are present in the olfactory epithelium of all vertebrates. In fish, amphibia, reptiles, and birds, they are secretory; in mammals, they generally are considered to be "non-secretory," although they may participate in the regulation of the mucous composition through micropinocytotic secretion and uptake. Goblet cells occur in the olfactory epithelium of fish and secrete a mucous product. Secretion from Bowman's glands and vasomotor activity in the olfactory mucosa are regulated by neural elements extrinsic to the primary olfactory neurons. Nerve fibers described in early anatomical studies and characterized by immunohistochemical studies contain a variety of neuroactive peptides and have several targets within the olfactory mucosa. Ultrastructural studies of nerve terminals in the olfactory mucosa have demonstrated the presence of adrenergic, cholinergic and peptidergic input to glands, blood vessels, and melanocytes in the lamina propria and of peptidergic terminals in the olfactory epithelium. The neural origins of the extrinsic nerve fibers and terminals are the trigeminal, terminal, and autonomic systems.