Calcitonin Gene-related Peptide-immunoreactive Nerve Fibers Research Articles

Cutaneous nerve fibre depletion in vibration white finger.

Vibration white finger or hand-arm vibration syndrome is the episodic blanching of the fingers in response to cold occurring in those who work with hand held vibrating tools. Clinically the condition differs from primary Raynaud's phenomenon as persistent paraesthesiae and pain are common in the hands and arms and these occur independently from the 'white attacks'. Symptoms can become severe enough to warrant a change of occupation. Industrial compensation may be awarded for vibration white finger but, at present, no simple or reliable objective diagnostic test is available. Calcitonin gene-related peptide (CGRP) is a neuropeptide with powerful vasodilator properties. A deficiency of immunoreactive CGRP nerve fibres has been previously demonstrated in the digital cutaneous microvasculature of patients with primary and secondary Raynaud's phenomenon with the distribution and quantity of other types of nerve fibres not being significantly altered. To determine if the innervation of the cutaneous microvasculature in vibration white finger was also abnormal skin biopsy samples from the fingers of 15 patients with vibration white finger, six healthy age matched controls who worked with vibrating machinery and 26 healthy age matched controls who were heavy manual workers without exposure to vibrating machinery were examined by immunohistochemistry. To try to correlate any histological abnormalities with clinical neurological deficit sensory nerve conduction studies have so far been performed in six patients with vibration white finger.(ABSTRACT TRUNCATED AT 250 WORDS)

Postnatal development of neuropeptide Y- and calcitonin gene-related peptide-immunoreactive nerves in the rat urinary bladder

The postnatal development of neuropeptide Y- and calcitonin gene-related peptide-immunoreactive (NPY-IR and CGRP-IR) nerve fibers in the rat urinary bladder was investigated using whole-mount preparations and cryostat sections. In newborn and 3-day-old rats, many NPY-IR nerve fibers were observed in the subserous and muscle layers. Many NPY-IR nerve cell bodies clustered at branching points of the subserous nerve bundles. Within 4 weeks after birth, these cell bodies drastically decreased in number and spread along the bundles, although the number of NPY-IR nerve fibers increased moderately. In contrast, CGRP-IR nerve fibers in newborn and 3-day-old rats were less developed, and no CGRP-IR nerve cell body was observed in any rat. However, CGRP-IR nerve fiber distribution in the urinary tissues conspicuously increased within 4 weeks after birth. Especially, an increase of the infraepithelial fibers showing a meshwork appearance was prominent in the fundus and corpus of the bladder. The infra- and intraepithelial CGRP-IR nerve meshwork of the ventral wall was more dense than that of the trigone. At 4 weeks, NPY-IR and CGRP-IR nerves were similar to those of the adult rat (8-12 weeks old). The present study suggests a correlation between the development of the peripheral nervous system in the urinary bladder and maturation of micturition behavior in the rat.

Calcitonin gene-related peptide immunoreactive nerve fibers in the developing salivary glands of the rat

The appearance and distribution of calcitonin gene-related peptide immunoreactive (CGRP-IR) nerve fibers was studied by indirect immunofluorescence microscopy in the developing salivary glands of the rat at daily age intervals from the 15th day in utero (i.u.) until birth and subsequently on the 2nd, 5th, 7th, 16th, 30th postnatal (p.n.) days. The findings were compared to samples of adult rats. CGRP-IR fibers appeared on day 20 i.u. both in parotid and submandibular glands. In submandibular glands, fibers were first seen surrounding the developing ductal branches, in the mesenchyme and also in association with developing ducts and blood vessels. In the parotid gland CGRP-IR fibers first appeared around ductal branches and blood vessels on day 20 i.u. and on day 21 i.u. CGRP-IR nerve fibers were found in the mesenchyme and around developing ducts. The density of CGRP-IR fibers was highest between the 2nd and 16th postnatal days, after which the amount of CGRP immunoreactivity slowly decreased to the levels of adult glands. The increase in a number of CGRP-IR nerve fibers especially around the ductal and vascular elements in the developing salivary glands indicates that they may play a role in the functional maturation of salivary glands.

Peptide-immunoreactive neurons and nerve fibres in lumbosacral sympathetic ganglia: Selective elimination of a pathway-specific expression of immunoreactivities following sciatic nerve resection in kittens

The distributions of peptide-immunoreactive nerve fibres and cell bodies in lumbosacral paravertebral sympathetic ganglia of young cats were analysed with antibodies to calcitonin gene-related peptide, enkephalin, neurotensin, somatostatin, substance P, galanin, neuropeptide Y and vasoactive intestinal polypeptide. Fairly dense networks of nerve fibres showing enkephalin-, neurotensin-, somatostatin- or substance P-like immunoreactivity were observed in the ganglia. Double-staining experiments revealed that enkephalin- and somatostatin-immunoreactive nerve fibres preferentially surrounded calcitonin gene-related peptide- and/or vasoactive intestinal polypeptide-immunoreactive cell bodies. Neurotensin- and substance P-immunoreactive nerve fibres were mainly associated with neurons showing neuropeptide Y and/or galanin-like immunoreactivity. Occasional nerves containing calcitonin gene-related peptide-, galanin-, neuropeptide Y- or vasocative intestinal polypeptide-like immunoreactivity were observed. These fibres did not seem to have any direct regional distribution within the ganglia. In kittens surviving for three months after early postnatal sciatic nerve resection, no calcitonin gene-related peptide-immunoreactive cell bodies could be detected in ganglia ipsilateral to the operation. In contrast, vasoactive intestinal polypeptide-like immunoreactivity, which partly co-exists with calcitonin gene-related peptide, was observed to the same extent as in control ganglia. Furthermore, almost all of the somatostatin-immunoreactive varicose nerve fibres had disappeared, whereas a fairly dense network of calcitonin gene-related peptide-immunoreactive nerve fibres could be observed. This change was paralleled by an increased content of nerve fibres that were immunoreactive to antibodies against the growth-associated protein GAP-43 (also known as B-50). The present findings suggest that experimental perturbations where postganglionic neurons are separated from their target areas by axotomy, not only induce differential changes in neurotransmitter expression in the principal ganglion cells, but also in preganglionic sympathetic neurons projecting to the ganglia. One possible explanation for the occurrence of an axotomy-induced network of calcitonin gene-related peptide-immunoreactive nerve fibres, is that extrinsic sensory nerve fibres grow into the ganglia after the sciatic nerve lesion. Thus, these findings seem to suggest one additional possibility with regard to the question of a possible interaction between sympathetic and sensory neurons after peripheral nerve injury.

Rapid proliferation of calcitonin gene-related peptide-immunoreactive nerves during healing of rat tibial fracture suggests neural involvement in bone growth and remodelling

The nervous system may be actively involved in bone repair and in remodelling of callous tissue in bone fractures, as well as in the regulation of nociceptive impulses from the site of the trauma. The aim of this study was to assess the distribution and nature of the periosteal innervation of normal control bone and during bone healing subsequent to fracture of rat tibiae at seven, 14 and 21 days after experimental fracture using immunocytochemistry and image analysis quantification of the neuronal marker protein gene product 9.5 and sensory neuropeptide calcitonin gene-related peptide. At seven days, periosteal protein gene product 9.5- and calcitonin gene-related peptide-immunoreactive fibres showed dense ramifications and terminal sprouting. In addition to periosteum, the nerve fibres were found in the middle of the callus interspersed with inflammatory cells and penetrating into secondary minor fractures. At days 14 and 21 many tortuous nerves were found in the periosteum but not in mid callus. Image analysis quantification revealed a uniform increased proliferation of nerves after seven days. At 21 days, the intercept countings showed in excess of a three-fold increase of calcitonin gene-related peptide-immunoreactive nerve fibres compared with the normal control group ( P ⩽ 0.0001) and were almost as numerous as protein gene product 9.5-immunoreactive fibres ( P < 0.005). It is postulated that calcitonin gene-related peptide-containing sensory innervation may have a potential importance in the fracture vascular control, angiogenesis and osteogenesis in addition to a protective role against excessive fracture movement. The results are consistent with the neural involvement in bone growth and remodelling.

Distribution, origin and plasticity of galanin-immunoreactivity in the rat carotid body

The distribution, origin and plasticity of galanin immunoreactivity in the rat carotid body was examined using an indirect immunofluorescence method. Galanin-immunoreactive nerve fibers were observed around the blood vessels as well as around the clusters of glomus and sustentacular cells. A double-immunofluorescence method revealed the coexistence of galanin- and calcitonin gene-related peptide-immunoreactivities in these nerve fibers. In the jugular, petrosal and nodose ganglia which supply the sensory nerve fibers to the carotid body, subpopulations of neurons showed both galanin- and calcitonin gene-related peptide-immunoreactivities. In the superior cervical ganglion, a few neurons were immunoreactive for galanin but not calcitonin gene-related peptide. While the nerve fibers showing both galanin- and calcitonin gene-related peptide-immunoreactivities disappeared after transection of the carotid sinus nerve, many galanin-immunoreactive nerve fibers without calcitonin gene-related peptide-immunoreactivity appeared throughout the operated carotid body. In addition, galanin-immunoreactive glomus cells which were not observed in the normal carotid body, were apparent at one and three days after transection of the carotid sinus nerve. At seven days after the carotid sinus nerve transection, the galanin-immunoreactive glomus cells disappeared. In the superior cervical ganglion, the number of galanin-immunoreactive neurons increased from one day after transection of the carotid sinus nerve. Within three days after the carotid sinus nerve transection in combination with superior cervical ganglionectomy, all galanin-immunoreactive nerve fibers disappeared, while many galanin-immunoreactive glomus cells appeared in the operated carotid body. At seven days after this operation, the number of galanin-immunoreactive glomus cells decreased and a few galanin-immunoreactive nerve fibers with or without calcitonin gene-related peptide-immunoreactivities appeared. Transection of the vagus nerve had no effect on the number or distribution of galanin-immunoreactivity in the carotid body. Disappearance of galanin- and calcitonin gene-related peptide-immunoreactive nerve fibers after transection of the carotid sinus nerve suggests that the majority of those nerve fibers originate from petrosal neurons which colocalize galanin- and calcitonin gene-related peptide-immunoreactivity. In addition, the carotid sinus nerve transection may cause the acquisition of galanin-immunoreactivity in originally immunonegative glomus cells, and in nerve fibers which probably originate from the superior cervical ganglion.

喉頭粘膜上皮のＳＰ，ＣＧＲＰ陽性線維に関する形態学的研究 種差について

This study was carried out to determine the different densities in laryngeal intraepithelium of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive (IR) nerve fibers in the dog, rat, guinea pig and cat. In the supraglottic and subglottic regions, the densities of SP and CGRP IR nerve fibers occured in decreasing order as follows: dog, rat, guinea pig and cat. Only a few fibers were found in the vocal folds of all species. We observed a greater density of CGRP IR nerve fibers than SP in all the animals studied. It was suggested that the difference in the distribution of SP and CGRP IR nerve fibers is related to differences in the sensory and reflex system of the larynx.

Distribution of calcitonin gene-related peptide nerve fibers in the canine larynx.

Immunohistochemistry was used to investigate the distribution pattern of calcitonin gene-related peptide (CGRP) nerve fibers in the laryngeal mucosa, glands and intrinsic muscles of the dog. CGRP immunoreactive nerve fibers were found more frequently than substance P immunoreactive nerve fibers in every region of the larynx. In the epithelia, CGRP nerve fibers were mainly found in the epiglottis, arytenoid region and subglottis. Many taste buds were observed in the arytenoid region and were densely innervated by the CGRP nerve fibers. In the lamina propria, the plexus of CGRP nerve fibers was present, with some of these fibers associated with blood vessels. Laryngeal glands were also innervated by a few CGRP nerve fibers. In the intrinsic laryngeal muscles, abundant immunoreactivity was observed and many motor end-plate-like structures were found with CGRP immunoreactivity. These findings strongly suggest that CGRP plays an important role in all of the sensory, motor and autonomic nervous systems of the larynx.

Calcitonin gene-related peptide (CGRP)-immunoreactive nerve plexuses in the renal pelvis and ureter of rats

The distribution of calcitonin gene-related peptide-immunoreactive nerve fibers in the renal pelvis and ureter was examined by immunohistochemistry using whole-mount preparations and cryostat sections. The patterns of innervation were contrasted between the pelvis and ureter; the immunoreactive nerve fibers in the pelvis ran parallel to the long axis of each of the circular and longitudinal muscle layers, causing a lattice-like appearance of the nerve fibers. In the ureter, the immunoreactive fibers were accumulated in the subepithelial region and the longitudinal muscle. In both the pelvis and ureter, a portion of the nerve fibers of smaller caliber showed a swollen or beaded structure; they were located in the musculature and beneath the epithelium extending for considerable distances. Ligation of the ureter caused a marked decrease in the immunoreactive nerves in the pelvis and the proximal portion of the ureter, suggesting that the axonal flow in the calcitonin gene-related peptide-containing neurons of the ureter runs towards the pelvis.

Ultrastructure of calcitonin gene-related peptide-immunoreactive nerve fibres in guinea-pig peribronchial ganglia

Calcitonin gene-related peptide-immunoreactive (CGRP-IR) nerves within guinea-pig peribronchial ganglia were studied at ultrastructural level using pre-embedding immunohistochemistry. Preterminal CGRP-IR axons were unmyelinated and contained singular immunoreactive dense core vesicles. CGRP-IR axon terminals were filled with numerous non-reactive small clear vesicles and few immunoreactive dense core vesicles. Some of these terminals were presynaptic to large neuronal processes emerging from local ganglion cells. Another population of presynaptic varicosities lack CGRP-IR. Within CGRP-IR terminals, non-reactive clear vesicles were clustered at the presynaptic membrane whereas CGRP-IR large vesicles remained in some distance from the synaptic cleft. The present observations indicate that: (1) at least two neurochemically different types of synaptic input exist to guinea-pig peribronchial ganglia. (2) CGRP-IR presynaptic terminals probably utilize a non-peptide transmitter for fast synaptic transmission, whilst the peptides are likely to be released parasynaptically and may act in a modulatory fashion.

Termination patterns of calcitonin gene-related peptide-immunoreactive nerve fibers in the dorsal horn of the human spinal cord

CGRP-immunoreactive varicose nerve fibers displayed three kinds of termination patterns in the cervical, thoracic and lumbar segments of the human spinal cord. Bundles of immunoreactive fibers formed a loose network in lamina I. A homogenous band of immunoreactive fibers filled lamina II. Multiple bundles of CGRP-positive fibers coursed through the superficial laminae towards deep portions of the grey matter. In the lumbar segments, in contrast to the cervical and thoracic segments, the bundles could be followed deep into the dorsal funiculus. Bundles of varicose immunoreactive fibers were seen to twine around the dendrites of neurons located in lamina I, in the dorsal funiculus of the lumbar segments and deep in the dorsal horn (laminae III-V). The corresponding types of large and medium-sized neurons were found in silver impregnated adjacent spinal cord sections. It is suggested that neurons in the above locations preferentially receive multiple contacts from CGRP-containing nerve fibers along their extensive dendritic arborizations (CGRP-target neurons).

Fine structure of calcitonin gene-related peptide-immunoreactive nerve fibres in the rat temporomandibular joint

The distribution and fine structure of these nerve fibres was examined by immunoelectron microscopy. CGRP-immunoreactive fibres were seen in the nerve bundles, blood vessels and periosteum around the condyle as well as in the disc. These nerve fibres were unmyelinated and had diameters varying from 200 to 600 nm. They were completely or partially enclosed by Schwann cell cytoplasm and did not form synaptic contact with any cells. CGRP-immunoreactive nerve fibres may be of sensory nature and this peptide could be involved in pain transmission and neurogenic inflammation.

Calcitonin gene-related peptide-immunoreactive nerve fibers in mandibular periosteum of rat: Evidence for primary afferent origin

Peptidergic neurons may play a role in the local regulation of bone mineralization. The neuropeptide vasoactive intestinal peptide (VIP) increases bone resorption in vitro, while calcitonin gene-related peptide (CGRP) has been shown to inhibit bone resorption in vitro. We have previously reported that sympathetic nerves with VIP-immunoreactivity innervate bone and periosteum. In the present study we sought to determine if CGRP fibers, like VIP fibers, exist in periosteum and what their origin might be. In whole-mount preparations of mandibular periosteum from rat, CGRP- and VIP-immunoreactive (IR) nerve fibers were present as networks within the periosteum. In preparations using two-color immunofluorescence, most CGRP-IR fibers were also immunoreactive for substance P (SP). In rats in which the subperiosteal space subjacent to the mandibular molars was injected with Fast blue or Fluoro-gold, retrogradely labeled cells were seen in ipsilateral trigeminal ganglia, superior cervical ganglia, and nodose ganglia. Individual cells labeled with both CGRP immunoreactivity and retrograde tracer were seen only in the mandibular portion of the trigeminal ganglion. These data suggest that CGRP-IR nerve fibers in periosteum may be of primary afferent origin. Given the reported effects of CGRP on bone mineralization, the present results suggest that primary afferent nerves containing CGRP and SP, as well as sympathetic nerves containing VIP, may play a role in focal bone remodeling.

Postnatal development of the innervation and paraganglia in the porcine pulmonary arterial bed.

The innervation of the pulmonary trunk and pulmonary arterial bed was studied in 17 pigs from birth to 6 months of age. After birth, the pulmonary trunk and extra- and intra-pulmonary arteries contained neurofilament and protein gene-product-immunoreactive nerve fibres in both the adventitia and media. The density of nerve fibres increased from birth to 2 months, this being most marked during the first 2 weeks of life. Most of the fibres in the media were presumed to be sympathetic in origin as they contained both neuropeptide tyrosine and tyrosine hydroxylase immunoreactivity. Fibres were associated with the vasa-vasorum and vascular smooth muscle running around the vessel, between the elastic laminae and smooth muscle cells, in the outer two-thirds of the media. Vasoactive intestinal polypeptide and calcitonin gene-related peptide-immunoreactive nerve fibres were found to be associated with the pulmonary trunk and extra-pulmonary artery, but generally not with the intra-pulmonary arteries. Tyrosine hydroxylase immunoreactivity was detected in the glomus cells at birth, but peptide immunoreactivity (enkephalin) was not demonstrated in paraganglia until 14 days of age. Adaptation to extra-uterine life is associated with rapid development changes in the innervation of the pig pulmonary trunk, extra- and intra-pulmonary arteries and in the expression of peptide immunoreactivity in both nerve fibres and glomus cells. These changes may have a role in the postnatal adaptation of the pulmonary circulation.

Calcitonin gene-related peptide-immunoreactive nerve fibres in the small intestine of the guinea-pig: electron-microscopic immunocytochemistry.

Calcitonin gene-related peptide (CGRP)-containing nerve fibres were identified by pre- and post-embedding electron-microscopic immunocytochemistry in the guinea-pig small intestine. Immunoreactive nerve processes were numerous in the mucosa and submucosa, especially in the connective tissue among the crypts of Lieberkühn. In some cases they were found in close apposition to epithelial cells. Many of the labelled nerve fibres were observed around blood vessels, especially arterioles. In the inner circular muscle layer, the immunoreactive nerve processes were found in close association (sometimes less than 40 nm) to smooth muscle cells. CGRP-positive terminals contained a predominance of electron-lucent synaptic vesicles (35-40 nm in diameter) together with a few large granular vesicles (80-120 nm in diameter). Post-embedding immunostaining, using the immunogold procedure, localized CGRP-immunoreactivity in large granular vesicles, 80-92 nm in diameter. These ultrastructural observations confirm that CGRP-containing nerve fibres exist in the small intestine and suggest that they may participate in the regulation of the smooth muscle activity, mucosal cell secretion and blood flow and, by analogy with other systems, a sensory role also seems likely.

Calcitonin gene-related peptide (CGRP): perivascular distribution and vasodilatory effects

The distribution of perivascular nerve fibers displaying calcitonin gene-related peptide (CGRP) immunoreactivity and the effect of CGRP on vascular smooth muscle were studied in the guinea-pig. Perivascular CGRP fibers were seen in all vascular beds. Generally, they were more numerous around arteries than veins. Small arteries in the respiratory tract, gastrointestinal tract and genitourinary tract had numerous CGRP fibers. The gastroepiploic artery in particular received a rich supply of such fibers. Coronary blood vessels had a moderate supply of CGRP fibers. In the heart, a moderate number of CGRP fibers was seen running close to myocardial fibers. The atria had a richer supply than the ventricles. Numerous CGRP immunoreactive nerve cell bodies and nerve fibers were seen in sensory (trigeminal, jugular and spinal dorsal root) ganglia. Sequential or double immunostaining with antibodies against substance P and CGRP suggested co-existence of the two peptides in nerve cell bodies in the ganglia and in perivascular fibers. In agreement with previous findings CGRP turned out to be a strong vasodilator in vitro as tested on several blood vessels (e.g. basilar, gastroepiploic and mesenteric arteries). Conceivably, perivascular CGRP/SP fibers have a dual role as regulator of local blood flow and as carrier of sensory information.

Calcitonin gene related peptide: a sensory transmitter in dental pulps?

Nerve fibers displaying calcitonin gene related peptide (CGRP) immunoreactivity occurred in dental pulps of several mammals, including man. The CGRP fibers were more numerous in the apical parts than in the coronal parts and were distributed around small blood vessels as well as in the pulpal stroma without any obvious relation to blood vessels. The trigeminal, spinal and jugular-nodose ganglia harbored a moderate supply of CGRP immunoreactive perikarya and nerve fibers. Immunocytochemic double staining revealed the coexistence of CGRP and SP in a population of perikarya in the sensory ganglia and suggested coexistence of the two peptides in perivascular nerve fibers in the cat dental pulp. The cervical sympathetic ganglia did not contain CGRP-immunoreactive perikarya. Cervical sympathectomy (studied in the guinea-pig and rat) did not affect the frequency or distribution of pulpal CGRP fibers. The distribution of CGRP fibers within the dental pulp and the presence of CGRP perikarya in sensory ganglia known to supply the dental pulps indicate that the pulpal CGRP fibers are sensory in nature and that CGRP together with SP may participate in the regulation of local blood flow and the response to local inflammation.