The distribution and chemical coding of neurons supplying the sphincter of Oddi in mammals

The major duodenal papilla (papilla of Vater) is an important structure associated with the biliary tract and, in some species, the pancreas. It usually represents a slight elevation on the intestinal mucosa where the dilated junction (ampulla of Vater) of the commmon bile duct and pancreatic duct enters the duodenum. The ampulla is surrounded by a specifically arranged muscle structure called the sphincter of Oddi (SO) which controls the flow of bile and pancreatic fluid. The function of the sphincter is regulated by a complex system that involves many hormonal and neural factors. The literature in the field contains detailed data on the morphology of the SO in a number of mammalian species. However, the comprehensive information about the anatomy and neurochemistry of the innervation of this structure is very limited. The present review article summarizes the current knowledge on the innervation of the SO in mammals. Special emphasis has been put on the localization and chemical coding of neurons contributing to this nerve supply

Immunohistochemical characterization of neurons in the vestibular ganglion (Scarpa’s ganglion) of the pig

The study was carried out on three 4-month old female pigs. All the animals were deeply anesthetized and transcardially perfused with 4% buffered paraformaldehyde (pH 7.4). Vestibular ganglia (VG) were collected and processed for double-labelling immunofluorescence method. The preparations were examined under the Zeiss LSM 710 confocal microscope equipped with adequate filter blocks. Neurons forming VG were round or oval in shape with a round nucleus in the center. The majority of them (58%) were medium (M) (31-50 μm in diameter) while 28 % and 14% were small (S) (up to 30 μm in diameter) or large (L) (above 50 μm in diameter) in size, respectively. Double-labeling immunofluorescence revealed that VG neurons stained for CGRP (approx. 81%; among them 70.5%, 26.2% and 3.3% were M, S and L in size, respectively), VACHT (57%; 63% M, 24% S, 13% L), Met-Enk (25%; 60% M, 12% S, 28% L), VIP (20%; 88% M, 6% S, L), NPY (15%; 67% M, 20% S, 13% L), GAL (15%; 74% M, 21% S, 5% L), SP (12%; 69% M, 25% S, 6% L) and NOS-positive (12%; 50% S, 50% M). The most abundant populations of intraganglionic nerve fibers were those which stained for CGRP or Met-Enk, whereas only single SP- or NOS-positive nerve terminals were observed

Morphology and immunohistochemical characteristics of the pterygopalatine ganglion in the chinchilla (Chinchilla laniger, Molina)

Histological and histochemical investigations revealed that the pterygopalatine ganglion (PPG) in the chinchilla is a structure closely connected with the maxillary nerve. Macro-morphological observations disclosed two different forms of the ganglion: an elongated stripe representing single agglomeration of nerve cells, and a ganglionated plexus comprising smaller aggregations of neurocytes connected with nerve fibres. Immunohistochemistry revealed that nearly 80% of neuronal cell bodies in PPG stained for acetylcholine transferase (CHAT) but only about 50% contained immunoreactivity to vesicular acetylcholine transporter (VACHT). Many neurons (40%) were vasoactive intestinal polypeptide (VIP)-positive. Double-staining demonstrated that approximately 20% of the VIP-immunoreactive neurons were VACHT-negative. Some neurons (10%) in PPG were simultaneously VACHT/nitric oxide synthase (NOS)- or Met-enkephaline (Met-ENK)/CHAT-positive, respectively. A small number of the perikarya stained for somatostatin (SOM) and solitary nerve cell bodies expressed Leu-ENK- and galanin-immunoreactivity. Interestingly about 5-8% of PPG neurons exhibited immunoreactivity to tyrosine hydroxylase (TH). Intraganglionic nerve fibres containing immunoreactivity to VACHT-, VIP- and Met-ENK- were numerous, those stained for calcitonin gene related peptide (CGRP)- and substance P (SP)- were scarce, and single nerve terminals were TH-, GAL-, VIP- and NOS-positive

Dispersal and immunohistochemical characteristics of neurons in the stem of the porcine vagus nerve

The present study investigated the distribution and chemical properties of nerve cell bodies within the trunk of the vagus nerve in juvenile female pigs (n=4) using double-labelling immunofluorescence. The neurons appeared mostly as single cells or formed streaks of cells or small ganglia. Many of the perikarya were cholinergic (VAChT-positive; VAChT+) or adrenergic (DβH+) in nature and no SP+ or CGRP+ neurons were encountered. There were no distinct left-right differences regarding the number and chemical coding of the neuronal somata, however, these characteristics significantly varied between particular nerve segments investigated. The vagosympathetic trunks, and thoracic and abdominal segments of the vagus nerve contained on average (the numerical values represent the means for both the left and right corresponding nerve segments) 142, 236, and 111 PGP 9.5-positive neurons, respectively. Proportions of cholinergic and adrenergic neurons were as follows: 0% and 100%, 54.2% and 33.2%, and 52.8% and 35.4%, respectively. Relatively many neurons in the thoracic and abdominal segments stained also for NOS (39.2% and 39.9%, respectively). It remains to be determined whether the porcine intravagal neurons represent a developmental relic, or whether they have any specific functional significance

The influence of botulinum toxin type A (BTX) on the immunohistochemical characteristics of noradrenergic and cholinergic nerve fibres supplying the porcine urinary bladder wall

Botulinum toxin (BTX) belongs to a family of neurotoxins which strongly influence the function of autonomic neurons supplying the urinary bladder. Accordingly, BTX has been used as an effective drug in experimental therapies of a range of neurogenic bladder disorders. However, there is no detailed information dealing with the influence of BTX on the morphological and chemical properties of nerve fibres supplying the urinary bladder wall. Therefore, the present study investigated, using double-labeling immunohistochemistry, the distribution, relative frequency and chemical coding of cholinergic and noradrenergic nerve fibers supplying the wall of the urinary bladder in normal female pigs (n=6) and in the pigs (n=6) after intravesical BTX injections. In the pigs injected with BTX, the number of adrenergic (DβH-positive) nerve fibers distributed in the bladder wall (urothelium, submucosa and muscle coat) was distinctly higher while the number of cholinergic (VAChT-positive) nerve terminals was lower than that found in the control animals. Moreover, the injections of BTX resulted in some changes dealing with the chemical coding of the adrenergic nerve fibers. In contrast to the normal pigs, in BTX injected animals the number of DβH/NPY- or DβH/CGRP-positive axons was higher in the muscle coat, and some fibres distributed in the urothelium and submucosa expressed immunoreactivity to CGRP. The results obtained suggest that the therapeutic effects of BTX on the urinary bladder might be dependent on changes in the distribution and chemical coding of nerve fibers supplying this organ

Immunohistochemical properties of motoneurons supplying the trapezius muscle in the rat

Combined retrograde tracing (using fluorescent tracer Fast blue) and double-labelling immunofluorescence were used to study the distribution and immunohistochemical characteristics of neurons projecting to the trapezius muscle in mature male rats (n=9). As revealed by retrograde tracing, Fast blue-positive (FB+) neurons were located within the ambiguous nucleus and accessory nucleus of the grey matter of the spinal cord. Immunohistochemistry revealed that nearly all the neurons were cholinergic in nature [choline acetyltransferase (ChAT)-positive]. Retrogradely labelled neurons displayed also immunoreactivities to calcitonin gene-related peptide (CGRP; approximately 60% of FB+ neurons), nitric oxide synthase (NOS; 50%), substance P (SP; 35%), Leu5-Enkephalin (LEnk; 10%) and vasoactive intestinal polypeptide (VIP; 5%). The analysis of double-stained tissue sections revealed that all CGRP-, VIP- and LEnk-immunoreactive FB+ perikarya were simultaneously ChAT-positive. The vast majority of the neurons expressing SP- or NOS-immunoreactivity were also cholinergic in nature; however, solitary somata were ChAT-negative. FB+ perikarya were surrounded by numerous varicose nerve fibres (often forming basket-like structures) immunoreactive to LEnk or SP. They were also associated with some CGRP-, NOS- and neuropeptide Y-positive nerve terminals

Immunohistochemical characterization of nerve elements in porcine intrinsic laryngeal ganglia

The present study investigated the chemical coding of neurons and nerve fibres in local laryngeal ganglia in pigs (n=5) using double-labelling immunohistochemistry. Virtually all the neurons were cholinergic in nature (ChAT- or VAChT-positive). Only very solitary, small nerve cells (presumably representing interneurons) stained intensely for adrenergic marker, DβH. Many neurons also contained immunoreactivity for NOS (91%), VIP (62.7%), NPY (24.7%), galanin (10%), SP (1.3%) and CGRP (5.3%). No neurons expressing somatostatin or Leu-enkephalin were observed. Nearly all the neuronal somata were densely supplied with varicose cholinergic nerve terminals, which presumably represented preganglionic axons, and some of them were also closely apposed with CGRP- and/or SP-positive varicose nerve endings, which were putative collaterals of extrinsic primary sensory fibres. In conclusion, this study has revealed that intrinsic neurons in the porcine larynx, like in many other mammalian species studied, should be classified as parasympathetic cholinergic neurons expressing biologically active substances, predominantly NOS and VIP. Furthermore, they are likely to receive inputs from not only preganglionic neurons but also primary sensory nerve cells. Finally, it appears that the information on the occurrence of the local laryngeal ganglia should be regularly included in textbooks dealing with the cranial portion of the parasympathetic nervous system in mammals

Caudal mesenteric ganglion in the sheep-macroanatomical and immunohistochemical study

The caudal mesenteric ganglion (CaMG) is a prevetrebral ganglion which provides innervation to a number of organs in the abdominal and pelvic cavity. The morphology of CaMG and the chemical coding of neurones in this ganglion have been described in humans and many animal species, but data on this topic in the sheep are entirely lacking. This prompted us to undertake a study to determine the localization and morphology of sheep CaMG as well as immunohistochemical properties of its neurons. The study was carried out on 8 adult sheep, weighing from 40 to 60 kg each. The sheep were deeply anaesthetised and transcardially perfused with 4% paraformaldehyde. CaMG-s were exposed and their location was determined. Macroanatomical observations have revealed that the ovine CaMG is located at the level of last two lumbar (L5 or L6) and the first sacral (S1) vertebrae. The ganglion represents an unpaired structure composed of several, sequentially arranged aggregates of neurons. Immunohistochemical investigations revealed that nearly all (99.5%) the neurons were DßH-IR and were richly supplied by VACHT-IR nerve terminals forming „basket-like" structures around the perikarya. VACHT-IR neurones were not determined. Many neurons (55%) contained immunoreactivity to NPY, some of them (10%) stained for Met-ENK and solitary nerve cells were GAL-positive. CGRP-IR nerve fibres were numerous and a large number of them simultaneously expressed immunoreactivity to SP. Single, weakly stained neurones were SP-IR and only very few nerve cells weakly stained for VIP