Peptide-containing nerve fibers in the respiratory tract of the ferret

Summary The ferret is widely used in functional and neuromorphological studies on the respiratory tract. We have examined the occurrence and distribution of peptide-containing and adrenergic nerve fibers (using dopamine--hydroxylase as a marker). Adrenergic nerve fibers and fibers storing vasoactive intestinal peptide have a widespread distribution along the entire respiratory tract. Adrenergic nerve fibers were found in the lamina propria, as well as around blood vessels and glands and in smooth muscle. Nerve fibers storing vasoactive intestinal peptide occurred in the epithelium, the lamina propria, around blood vessels and glands, and among muscle bundles. Substance P-, neurokinin A- and calcitonin gene-related peptide-containing nerve fibers predominated beneath and within the epithelium along the entire respiratory tract. Neuropeptide Y-containing nerve fibers were prominent among smooth muscle bundles and around glands. The blood vessels in the wall of the airways were richly supplied with peptidecontaining nerve fibers and adrenergic fibers. Ganglia located over the outer or dorsal surface of the tracheal wall harbored vasoactive intestinal peptide-containing nerve cell bodies. Substance P and neurokinin A invariably coexisted in the same nerve fibers. Further, coexistence of substance P/neurokinin A and calcitonin gene-related peptide was observed in the nerve fibers associated with the epithelium. Vasoactive intestinal peptide, neuropeptide Y and occasionally also substance P coexisted in the population of nerve fibers associated with blood vessels and smooth muscle. Many adrenergic nerve fibers contained neuropeptide Y.     

Peptidergic and aminergic neurotransmitters of the exocrine pancreas of the Houbara bustard (Chlamydotis undulata)

The immunochemical distribution of peptidergic and aminergic neurotransmitters in the exocrine pancreas of the Houbara bustard, Chlamydotis undulata, was determined. Immunoreactivity to choline acetyltransferase (ChAT), vasoactive intestinal polypeptide (VIP), and galanin (Gal) occurred mainly as varicose terminals in the walls of capillaries around the acini and arterioles within the connective tissue. Neuronal cell bodies immunoreactive to ChAT were infrequently observed. Neuropeptide Y (NPY), pancreatic polypeptide (PP), and somatostatin (Som) were observed mainly in intra-acinar cell bodies but nerve fibers immunoreactive to these neuropeptides were also seen along the basal surfaces of the acini. Immunoreactivity to NPY and PP was also discernible in cells of the pancreatic ducts. In addition, NPY occurred as varicose terminals in vessels around the ducts. SP occurred rarely in interacinar ganglia. The distribution of tyrosine hydroxylase (TH) was similar to that of ChAT and, in addition, the occasional TH immunoreactive intra-acinar neuronal cell body was observed. Neuronal nitric oxide synthase (nNOS) occurred in neuronal cell bodies among the acinar cells as well as nerve fibers along the bases of the acini. The potential roles of these peptidergic and aminergic neurotransmitters in the neurohormonal control of pancreatic secretion are discussed.     

The distribution and origin of nerve fibers immunoreactive for substance P and neurokinin A in the anterior buccal gland of the rat

The distribution and origin of substance P (SP) and neurokinin A (NKA) were studied in rat in the anterior buccal glands, which are minor mucous salivary glands. Indirect immunofluorescence staining showed moderate SP and NKA innervation of salivary acini and interlobular ducts, whereas blood vessels were more sparsely innervated, and there were few nerve fibers in the stroma and around the intralobular ducts. About 10%–20% of the trigeminal ganglion cells showed equally strong immunoreactivity to both SP and NKA. Unilateral denervation of the branches of the trigeminal nerve caused complete disappearance of the stromal fibers and greatly reduced the number of all other SP-immunoreactive and NKA-immunoreactive nerve fibers. In the superior cervical ganglia, SP and NKA immunoreactivity was restricted to small intensely fluorescent cells; SP and NKA immunoreactivity was absent from principal ganglionic cells, and thus sympathectomy had no any effect on the number or distribution of fibers immunoreactive for SP and NKA in the anterior buccal glands. The fibers remaining after sensory denervation could have been of parasympathetic origin, indicating a dual origin of nerves immunoreactive for SP and NKA in these glands. The present data demonstrate that the major part of the glandular SP and NKA innervation in the minor salivary glands derives from the trigeminal ganglia. The distribution of the peripheral nerve fibers indicates that they may play a role in the delivery of potent neuropeptides involved in the vascular, secretory, and motor (myoepithelial cells) functions of salivary glands.     

Peptidergic innervation of the major salivary glands of the ferret

In parotid, sublingual and submandibular glands of the ferret, morphological correlates were looked for, using immunocytochemistry, to previous physiological findings showing parasympathetic "atropine-resistant" salivary secretion and neuropeptide-evoked salivation in this species. Nerve fibers storing VIP were numerous in association with acini, ducts and blood vessels, while the number of fibers storing substance P was moderate and those containing CGRP and galanin few; also the number of NPY-containing fibers was low around acini and ducts but relatively high around vessels. Sympathectomy eliminated all NPY- and almost all dopamine beta-hydroxylase-containing fibers. Parasympathectomy of the parotid gland resulted in a total loss of the VIP-containing fibers, and a profound reduction in the number of substance P- and CGRP-containing fibers.     

Distribution of immunoreactive neuropeptides in the pancreas of the bullfrog,Rana catesbeiana,demonstrated by immunofluorescence

Indirect double immunofluorescence labelling for eight neuropeptides in the pancreas of the bullfrog, Rana catesbeiana, demonstrated the occurrence, distribution, and coexistence of certain neuropeptides in the exocrine and endocrine pancreas. Immunoreactivity of substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), FMRFamide (FMRF), and galanin (GAL) was localized in nerve fibers distributed between the acini and around the duct system and vasculature of the exocrine pancreas. In these regions, CGRP-immunoreactive fibers were more numerous than those containing the other five peptides. Almost all SP fibers showed coexistence of SP with CGRP, and about one third of fibers also showed coexistence of SP with VIP, NPY, FMRF, and GAL. In the endocrine pancreas, SP, CGRP, VIP, and GAL were recognized in the nerve fibers around and within the islets of Langerhans, and VIP and GAL fibers were more numerous than SP and CGRP fibers. All CGRP fibers, and about half of the VIP and GAL fibers were immunoreactive for SP. NPY- and FMRF-immunoreactive cells were found at the periphery of the islets. These findings suggest that the exocrine and endocrine pancreatic functions of the bullfrog are under the control of peptidergic innervation.     

Met5-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerve fibers in the major salivary glands of the rat: evidence for both sympathetic and parasympathetic origin

Summary The localization of the proenkephalin A-derived octapeptide, Met⁵-enkephalin-Arg⁶-Gly⁷-Leu⁸ (MEAGL), was studied in the major salivary glands of Sprague-Dawley and Wistar rats with the indirect immunofluorescence method. MEAGL-immunoreactive nerve fibers were found around the acini, along intra-and interlobular salivary ducts and in close contact with blood vessels. In the parotid and submandibular glands tyrosine hydroxylase (TH) immunoreactivity was observed in nerve fibers around the acini, in association with intra- and interlobular salivary ducts and around blood vessels, while in the sublingual gland TH-immunoreactive nerve fibers were only seen around blood vessels. Parasympathetic neurons in submandibular ganglia contained MEAGL immunoreactivity. Moderate TH immunoreactivity was seen in some neurons of the submandibular ganglia. A subpopulation of sympathetic principal neurons in the superior cervical ganglion were immunoreactive for both MEAGL and TH. In the trigeminal ganglion, no MEAGL-immunoreactive sensory neurons or nerve fibers were observed. Superior cervical ganglionectomies resulted in a complete disappearance of TH-immunoreactive nerve fibers, while MEAGL-immunoreative nerve fibers were still present in the glands. The presence of MEAGL immunoreactivity in neurons of both sympathetic superior cervical ganglia and parasympathetic submandibular ganglia and the results of superior cervical ganglionectomies suggest, that MEAGL-immunoreactive nerve fibers in the major salivary glands of the rat have both sympathetic and parasympathetic origin.     

Antigenic profile of the human lacrimal gland.

The antigenic profile of 13 normal formalin-fixed, paraffin-embedded human main and accessory lacrimal glands, biopsied from patients aged 11 to 78 years, was studied using a panel of 27 polyclonal and monoclonal antibodies. Secretory cells of lacrimal acini reacted with antibodies to S-100 protein and simple epithelium-type cytokeratins CK 7, CK 8, CK 18, and CK 19. Their luminal membranes were labeled with antibodies to carcinoembryonic antigen, epithelial membrane antigen, and epithelial glycoproteins recognized by Ber-EP4. Myoepithelial cells were often immunopositive for S-100 protein, vimentin, glial fibrillary acidic protein (GFAP), and alpha-smooth muscle actin. More rarely, they reacted with antibodies recognizing CK 5, CK 13, and CK 14, which consistently labeled the basal cells of lacrimal ducts. Unlike myoepithelial cells, basal ductal cells were immunopositive for CK 7, CK 8, CK 18, and CK 19. In main excretory ducts, dendritic melanocyte-like cells co-expressing vimentin and S-100 protein intermingled with ductal epithelial cells. The luminal cells of lacrimal ducts basically paralleled secretory cells in their antigenic profile, although they lacked Ber-EP4 and were immunopositive for CK 4. Antibodies to neuron-specific enolase and synaptophysin reacted with nerve fibers among negatively reacting secretory acini. This antigenic profile closely parallels that of salivary glands and provides a basis for studies of lacrimal gland pathology.     

Neuronal galanin is widely distributed in the chicken respiratory tract and coexists with multiple neuropeptides

Summary The mammalian airways are known to be richly innervated by several types of peptide-containing nerve fibers. Galanin-containing fibers are, however, comparatively few. The results of the present immunocytochemical study indicate that the chicken airways receive a notably dense supply of galanin-storing fibers. Other major neuropeptides were neuropeptide Y, vasoactive intestinal peptide and substance P. Nerve fibers containing these peptides were distributed in the trachea, main bronchi, and the lungs. Minor nerve fiber populations contained calcitonin generelated peptide, enkephalin and gastrin-releasing peptide. In the trachea and main bronchi the majority of peptidecontaining nerve fibers was distributed beneath and sometimes also within the epithelium; fibers were fewer in the lamina propria. In the lungs they occurred both in association with the epithelium of small bronchi and in the septa. Adrenergic nerves (using tyrosine hydroxylase as marker) were predominantly distributed in the lamina propria among bundles of smooth muscle and blood vessels. In the nerve fibers associated with the epithelium and in nerve cell bodies in local ganglia of the tracheal wall, galanin was found to coexist with several other neuropeptides (neuropeptide Y, vasoactive intestinal peptide and substance P) suggesting co-expression of multiple neuropeptide genes in the same population of neurons.     

An immunohistochemical survey of endocrine cells and nerves in the proximal small intestine of the platypus,Ornithorhynchus anatinus

The relative frequencies of endocrine cells and peptidergic nerve elements in the proximal small intestine of the adult platypus were studied by immunohistochemistry. Six kinds of endocrine cells - serotonin (5-HT)-, somatostatin-, gastrin-, motilin-, cholecystokinin (CCK)- and bovine pancreatic polypeptide (BPP)-immunoreactive cells - were identified in this study. These endocrine cells were found most frequently in the intestinal glands, in moderate numbers in the tubular ducts and were infrequent in the surface folds. 5-HT-immunoreactive cells were most numerous, somatostatin-, gastrin-, motilin- and BPP-immunoreactive cells were moderately numerous, whereas CCK-immunoreactive cells were rare. Five kinds of neuropeptides: substance P, vasoactive intestinal polypeptide (VIP), gastrin releasing peptide (GRP), somatostatin and leu-enkephalin, were detected in the intramural nerve elements. Substance P-, VIP- and GRP-immunoreactive nerve fibers were found most frequently in the lamina propria mucosae of the surface folds. The relationships between the possible functions of the peptides and amine detected in this study as well as the characteristic structure of the digestive tract of the adult platypus are discussed.     

Origin of galanin in nerves of cat airways and colocalization with vasoactive intestinal peptide

Galanin is a 29 amino acid residue neuropeptide. In mammalian airways, galanin is found in nerve fibers associated with airway smooth muscle, bronchial glands, and blood vessels, and in nerve cell bodies of airway ganglia. The present study was conducted to determine if galanin-containing fibers in the walls of feline airways originate from the nerve cell bodies of airway ganglia. The colocalization of galanin with vasoactive intestinal peptide was also investigated. Organotypic cultures of cat airways were held in culture for 0 (nonculture control), 3, 5, and 7 days. After each culture period, the distribution of galanin and the colocalization of galanin with vasoactive intestinal peptide were determined by immunocytochemistry. Galanin-containing fibers were found in bronchial smooth muscle, around bronchial glands and in the walls of bronchial arteries and arterioles throughout the culture period. Nerve fibers and cell bodies containing both galanin and vasoactive intestinal peptide were observed after all culture periods. Nerve fibers and cells bodies that contained galanin frequently contained vasoactive intestinal peptide as well, but nerve fibers with only galanin or vasoactive intestinal were also observed. Galanin- and vasoactive intestinal peptide-containing nerve fibers and cell bodies were both well maintained throughout the culture period. The findings show that galanin-containing nerve fibers associated with bronchial smooth muscle, bronchial glands, and bronchial arteries, originate from nerve cell bodies of intrinsic airway ganglia, and that galanin and vasoactive intestinal peptide are frequently colocalized in these neurons.     

Neuropeptides in guinea pig trachea: Distribution and evidence for the release of CGRP into tracheal lumen

The airways of the guinea pig are richly innervated by peptide-containing nerve fibers. Among the most abundant neuropeptides are calcitonin gene-related peptide (CGRP) and substance P (SP), which are stored in nerve fibers located predominantly within and beneath the epithelium, and vasoactive intestinal peptide (VIP), which is located in fibers running mainly among smooth muscle bundles and seromucous glands. Sensory denervation (capsaicin treatment) of adult guinea pigs caused an almost total disappearance of CGRP- and SP-containing nerve fibers, while the density of VIP-containing nerve fibers located in smooth muscle seemed to increase. In the isolated trachea, perfused luminally, CGRP was found to appear in the intraluminal fluid after exposure to capsaicin but not after electrical vagal stimulation. CGRP concentrations in the tracheal wall did not change significantly. Luminally applied CGRP did not affect smooth muscle tension, measured as intraluminal volume changes.     

Cholinergic innervation of the pancreas in the sheep

Antibodies raised against vesicular acetylcholine transporter (VAChT) were applied to study the cholinergic innervation pattern of the pancreas of the sheep. To determine whether the cholinergic pancreatic neuronal elements contain tyrosine hydroxylase (TH), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) or substance P (SP) double immunocytochemistry was used. A moderate number of VAChT-immunoreactive (IR) nerve terminals were distributed between the acini, whereas only single cholinergic nerve fibres innervated the interlobular connective tissue. VAChT-positive nerve fibres supplying the endocrine pancreas were found only occasionally. The pancreatic blood vessels and ducts system were devoid of VAChT-containing nerve endings. All intrapancreatic neurons studied showed immunoreactivity to VAChT, but intrapancreatic ganglia were not innervated with cholinergic nerve fibres. The colocalization of VAChT and TH or VAChT and SP was detected in distinct populations of nerve fibres localized amongst the acini, but not within the islet nor in the connective tissue. Single VAChT-IR nerve terminals co-expressing NPY were distributed around the acini, islets as well as in the connective tissue septa. A moderate number of VAChT-IR/VIP-IR nerve endings were located in the exocrine pancreas, whereas the islets and connective tissue were innervated with VAChT/VIP-containing nerve fibres only occasionally. In the vast majority of VAChT-positive intrapancreatic perikarya the presence of TH was additionally found. A moderate number of VAChT-IR intrapancreatic perikarya co-expressed NPY, SP or VIP. The results of the present study demonstrate species-dependent cholinergic innervation pattern of the pancreas of the sheep. The co-localization of VAChT with the neuropeptides suggests the existence of functional interactions influencing the ovine pancreas (mainly exocrine) activity.     

Calcitonin gene-related peptide-like immunoreactivity in nerve fibers in the human skin. Relation to fibers containing substance P-, somatostatin- and vasocactive intestinalpolypeptide-like immunoreactivity

Calcitonin gene-related peptide-like immunoreactivity was demonstrated in in sensory nerve fibers in the epidermis and dermis as free nerve endings and around blood vessels and hair follicles of the human finger pad and arm skin. The vast majority of the calcitonin gene-related immunoreactive fibers was shown to display also substance P-like immunoreactivity and a few fibers in the dermis were somatostatin positive. No fibers displaying both substance P and somatostatin-like immunoreactivity were found but a few substance P immunoreactive fibers in the dermis-epidermis region were found to contain also vasointestinal polypeptide-like immunoreactivity. In the sweat glands, abundant calcitonin gene-related peptide positive, but substance P negative, fibers were observed with a similar distribution pattern as the vasoactive intestinal polypeptide immunoreactive fibers and these fibers were suggested to be of sympathetic origin.     

Calcitonin gene-related peptide-like immunoreactivity in nerve fibers in the human skin

Summary Calcitonin gene-related peptide-like immunoreactivity was demonstrated in in sensory nerve fibers in the epidermis and dermis as free nerve endings and around blood vessels and hair follicles of the human finger pad and arm skin. The vast majority of the calcitonin generelated immunoreactive fibers was shown to display also substance P-like immunoreactivity and a few fibers in the dermis were somatostatin positive. No fibers displaying both substance P and somatostatin-like immunoreactivity were found but a few substance P immunoreactive fibers in the dermis-epidermis region were found to contain also vasointestinal polypeptide-like immunoreactivity. In the sweat glands, abundant calcitonin gene-related peptide positive, but substance P negative, fibers were observed with a similar distribution pattern as the vasoactive intestinal polypeptide immunoreactive fibers and these fibers were suggested to be of sympathetic origin.     

Distribution of galanin-immunoreactive nerve fibers in the carotid labyrinth of the bullfrog,Rana catesbeiana: comparison with substance P-immunoreactive fibers

Immunoreactivity of galanin (GAL) was detected in the nerve fibers distributed within the intervascular stroma of the bullfrog carotid labyrinth. GAL-immunoreactive fibers are numerous, and some are close to the sinusoidal plexus. Most GAL fibers appear as thin processes with some varicosities. A combination of indirect double immunofluorescence labelling and image processing clearly demonstrated that the distribution patern of GAL fibers is different from that of SP fibers. This indicates that GAL and SP do not coexist in the same nerve fibers. The role of GAL fibers may be different from that of previously reported neuropeptides (substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, neuropeptide Y, and others) as a neuromodulator in controlling vascular tone of the labyrinth.     

Distribution and origin of vasoactive intestinal polypeptide-like immunoreactive fibers in the central amygdaloid nucleus of the rat: an immunocytochemical analysis

We studied the distribution of vasoactive intestinal polypeptide-like immunoreactive (VIPLI) fibers in the central amygdaloid (AC) nucleus of the rat, using indirect immunofluorescence and the origins of such fibers using a combination of retrograde tracing with immunocytochemistry. VIPLI fibers formed a dense fiber plexus in the lateral subdivision of the AC nucleus, but other subdivisions showed little immunoreactivity. Destruction of the supramammillary (SuM) region and the adjacent lateral hypothalamus, both of which contained a group of VIPLI neurons, resulted in the marked reduction of VIPLI fibers in the ipsilateral AC nucleus, indicating that many of the fibers in the AC nucleus originate from these two areas. This assumption was supported by the finding that injection of fast blue dye into the AC nucleus labeled the VIPLI neurons in the SuM region and lateral hypothalamus.     

Development of the labial gland of the ponerine ant Pachycondyla obscuricornis (Hymenoptera, Formicidae) during the pupal stage

The labial gland of adult workers of the ant Pachycondyla obscuricornis is made up of many acini, each consisting of one central cell surrounded by approximately 10 parietal cells. Both cell types are associated with a system of ramified canaliculi that remove the secretion towards a ductule outside the acinus. These ductules, each associated with one acinus, fuse together and form a ramified system of ducts, ending in two paired ducts. These paired ducts widen to form a reservoir and anteriorly join into a common unpaired duct, which ends at the base of the labium. During development in the pupal stage, epithelial acini are formed first, consisting of a monolayered epithelium lining a central lumen. In these acini, one cell grows out to become the central cell, while the others will re-arrange around it to form the parietal cells. At the end of the pupal stage, the canaliculi are formed inside the acini by the central and parietal cells that secrete a lipidic substance and a cuticle. This gland type, which also occurs in some other Hymenoptera, is structurally different from the epithelial glands and the glands consisting of bicellular units, that have been traditionally distinguished until now.     

Immunohistochemical properties of nerve fibres supplying accessory male genital glands in the pig. A colocalisation study

 Immunohistochemical studies have been performed to investigate the occurrence and coexistence of two catecholamine-synthesising enzymes, tyrosine hydroxylase and dopamine-β-hydroxylase, and several neuropeptides, including neuropeptide Y, vasoactive intestinal polypeptide, Leu⁵-enkephalin, somatostatin, calcitonin gene-related peptide and substance P, in nerve fibres supplying porcine accessory genital glands, the seminal vesicles, prostate (body and the disseminated part) and bulbourethral glands. Three major populations of nerve fibres supplying non-vascular elements of the glands have been distinguished (from the largest to the smallest one): (1) noradrenergic fibres, the majority of which contain Leu⁵-enkephalin, neuropeptide Y or, to a lesser extent, somatostatin, (2) non-noradrenergic, putative cholinergic fibres containing vasoactive intestinal polypeptide, neuropeptide Y and/or somatostatin and, (3) non-noradrenergic, presumably sensory fibres, containing calcitonin gene-related peptide and substance P. Whilst the coexistence patterns within nerves supplying particular glands are similar, the density of innervation varies between the organs. The innervation of the seminal vesicles and prostatic body is more developed than that of the disseminated part of the prostate and bulbourethral glands. The majority of noradrenergic fibres related to blood vessels contain neuropeptide Y only, while the non-noradrenergic nerves contain mainly vasoactive intestinal polypeptide. The possible function and origin of particular nerve fibre populations are discussed. Accepted: 16 November 1998     

Neuropeptidergic regulation of bone resorption and bone formation

Immunohistochemical studies have revealed an extensive network of nerve fibers in the vicinity and within the skeleton, not only in the periosteum of bone but also in cortical and trabecular bone as well as in the bone marrow. Phenotyping of the skeletal nerve fibers have demonstrated the expression of a restrictive panel of different signalling molecules including neuropeptides, neurotransmitters and neurotrophins. In this review, the presence of receptors for the neuropeptides vasoactive intestinal peptide, calcitonin gene-related peptide and substance P on osteoblasts and osteoclasts and the capacity of these receptors to regulate bone formation, osteoclast formation and activity are described. These findings, together with data obtained by chemically and surgically targeted nerve deletion and observations made in paraplegic patients, strongly suggest that neuro-osteogenic interactions play an important role in skeletal function.     

The sympathetic and parasympathetic nature of neuropeptide Y-immunoreactive nerve fibres in the major salivary glands of the rat

Summary The distribution and origin of neuropeptide Y in the major salivary glands of the rat was studied by indirect immunofluorescence technique. Numerous nerve fibres immunoreactive for the peptide were seen in the parotid and sublingual glands. Most of the fibres were located around blood vessels and salivary acini. In the submandibular gland the number of immunoreactive nerve fibres around the acini was lower in comparison with that in the parotid and sublingual glands. Some immunoreactive nerve fibres were also found around or along intra- and interlobular ducts in all major salivary glands.A large number of the neuropeptide-containing neuronal cell bodies and nerve fibres were detected in the sympathetic superior cervical ganglion. Sympathetic postganglionic nerve trunks of this ganglion contained numerous immunoreactive nerve fibres as well. A subpopulation of the neuronal cell bodies in the submandibular ganglion were immunoreactive to neuropeptide Y.Both uni- and bilateral superior cervical ganglionectomies caused a significant decrease in the number of immunoreactive nerve fibres around the blood vessels in all the major salivary glands. However, these denervations did not affect the density of nerve fibres around the acini and ducts. On the contrary, unilateral parasympathetic denervation by sectioning the auriculotemporal nerve reduced the fibres around the secretory acini in the parotid gland remarkably, while only a minor reduction in the density of immunoreactive fibres associated with the blood vessels of the gland was detected. Unilateral electrocoagulation of the trigeminal nerve branches caused no detectable change in the density of immunoreactive nerve fibres in any of the major salivary glands.On the basis of the present findings it is concluded that neuropeptide Y-reactive nerve fibres present in all major salivary glands around the blood vessels seem to be mainly sympathetic, whereas those around the acini and ducts seems to be of parasympathetic origin.