Anatomical classification of feline congenital extrahepatic portosystemic shunts based on CT angiography: A SVSTS and VIRIES multi-institutional study in 231 cats

The prevalence of anatomical-based subtypes of feline congenital extrahepatic portosystemic shunts (EHPSS) has not been completely elucidated. The goal of this study was to use CT angiography to create an anatomical-based nomenclature system for feline congenital EHPSS. Additionally, subjective portal perfusion scores were generated to determine if intrinsic portal vein development was associated with different shunt conformations or patient age at the time of CT. The SVSTS and VIRIES list services were used to recruit cases. Data collected included patient DOB, gender, breed, weight, CT date, and reported diagnosis. Shunts were classified based upon (1) the shunt portal vessel(s) of origin, (2) the shunt systemic vessel(s) of insertion, and (3) any substantial portal vessels contributing to the shunt. Additionally, hepatic portal perfusion was subjectively scored between 1 (poor/none) and 5 (good/normal) based on the caliber of the intrahepatic PVs. A total of 264 CT scans were submitted from 29 institutions. Due to exclusion criteria, 33 (13%) were removed, leaving 231 CT scans to be included. Twenty-five different EHPSS anatomies were identified with five classifications accounting for 78% of all shunts (LGP [53%], LGC-post [11%], LCG [7%], LGC-pre [4%], and PC [4%]). Shunt origin involved the left gastric vein in 75% of the described classifications. Significant differences were identified among the five most common shunt types with respect to age at the time of CT scan (P = .002), breed (P < .001), and subjective portal perfusion score (P < .001). This refined anatomical classification system for feline EHPSS may enable improved understanding, treatment comparisons, and outcome prediction for cats with these anomalies.

Clinical outcomes for 20 cats with congenital extrahepatic portosystemic shunts treated with ameroid constrictor ring attenuation (2002-2020)

OBJECTIVE

To report the clinical perioperative, short-term, and long-term outcomes for cats undergoing ameroid ring constrictor (ARC) attenuation of a congenital extrahepatic portosystemic shunt (EHPSS).

STUDY DESIGN

Retrospective case series from a single veterinary teaching hospital (2002-2020).

ANIMALS

Twenty client-owned cats with EHPSS.

METHODS

Data collected from medical records included signalment, history, physical examination, clinicopathologic testing, medications, diagnostic imaging, intraoperative findings, perioperative complications, and postoperative clinical outcomes. Long-term clinical outcome was obtained from a standardized owner interview or medical records.

RESULTS

Perioperative complications were reported in five cats out of 20, including blindness (two cats), ascites (one cat), head pressing (one cat), and seizures and death (one cat). Short-term clinical outcome was excellent in 14/18 cats, good in 2/18 cats, and poor in 2/18 cats that were available for follow up, and long term clinical outcome was excellent in 15/18, good in 1/18 cats, and poor in 2/18 cats that were available for follow up.

CONCLUSION

Long-term clinical outcome was good or excellent in 16/18 of cats available for follow up. Perioperative complications were reported in five cats.

CLINICAL SIGNIFICANCE

Surgical attenuation of EHPSS with an ARC can result in resolution of clinical signs and biochemical abnormalities in the majority of cats. The perioperative complication rate for feline patients with EHPSS attenuated with an ARC was lower than reported historically. Seizures may persist in the long term despite normal bile acid stimulation test results, complete blood count, and biochemistry analysis.

Single center retrospective clinical audit and comparison of outcome between epicardial and transvenous endocardial permanent pacemaker implantations in dogs

The aim of this retrospective cohort study was to provide a single-center clinical audit of complications for single chamber permanent pacemaker implantation (PPI) techniques and determine if the clinical parameters, PPI technique or complications were associated with outcome. The electronic medical records were searched for dogs treated for bradyarrhythmia with PPI. Data related to presenting complaint, signalment of the dog, ECG diagnosis, echocardiographic findings, PPI technique, and programing of the pacemaker were recorded. Survival length (days) was recorded as the last veterinary visit; if the dog was dead the reason was documented. Cumulative survival of each pacemaker was examined by a Kaplan-Meier survival curve and the two techniques compared with a logrank test. Chi-square was used to determine the association between major complications and death. A total of 66 dogs with 52 transvenous and 30 epicardial PPIs were included. All epicardial pacemakers were implanted via transdiaphragmatic approach. A total of 31 life-threatening complications were reported. There were nine deaths related to major complications (13.6% of the study sample). The median follow-up period was 366 days, with a median survival of 255 days, and a significant difference in cumulative survival of each pacemaker (P = 0.01) between epicardial (93 days, range 0-1882 days) and transvenous (334 days, range 0-2745) PPIs but no significant difference in cumulative survival between the two techniques when only the first pacemaker was considered (p = 0.07). The presence of a major complications had a significant association with death due to pacemaker complications (P<0.001). The decision to perform epicardial PPI in failed transvenous PPI patients may have skewed the cumulative survival as was evident in the lack of significant difference in survival when only first PPI were examined. Major complication rates between the two techniques were similar and the authors consider both techniques equally reliable to manage symptomatic bradycardia in dogs.

Local wound management: A review of modern techniques and products

Management of wounds is a commonly performed and essential aspect of small animal veterinary medicine. Appropriate wound management is a difficult art to master, due to the inherent complexity of the clinical scenario, as well as the ever-evolving nature of the field with the constant addition of new products and techniques. This article reviews key concepts that may help the practitioner better understand the natural process of wound healing, factors that delay healing and strategies to help improve the local wound environment to make it more conducive to healing during open wound management. The concept of wound bed preparation is defined before common local wound management strategies, such as wound lavage and debridement, are discussed in more detail. Key aspects of the management of biofilms and appropriate use of antimicrobial agents are also reviewed. Finally, the concept of moist wound healing and its impact in modern wound management is explained before a broad variety of types of wound dressings are reviewed, with a particular focus on active dressings.

Repeatability and accuracy of a novel, quantitative radiographic method for differentiating normal canine sacroiliac joints from joints with subluxation or luxation: Pilot study

Canine sacroiliac (SI) joint subluxation or luxation is most commonly diagnosed based on qualitative radiographic assessments. Aims of this two-part, retrospective, diagnostic accuracy, pilot study were to develop and evaluate a novel quantitative method based on measuring the angle between a line connecting the iliac wings and parallel lines across three anatomical landmarks (cranial endplate of L7, caudal endplate of L6, cranial endplate of L6) on a single ventrodorsal radiograph. For the first part of the study, angle measurements from a single observer were compared for 20 normal canine pelvic radiographs and 20 pelvic radiographs with SI luxation or subluxation. Mean values significantly differed between datasets (P < 0.001). The angles for the normal pelves ranged from 0.6° to 1.5°, while abnormal angles ranged from 3.8° to 7.1°. For the second part of the study, a dataset of 25 normal and 25 abnormal canine pelvic radiographs was evaluated using the novel technique by three blinded readers with varying levels of expertise at two different time points. There was excellent reliability among the three readers with an intraclass correlation (ICC) value of 0.90 and an excellent agreement between day 0 and day 30 readings with an ICC value of 0.91. It was also determined that a cut-off angle of 2.0°, using the line parallel to the cranial endplate of L6, provided overall the best accuracy, sensitivity, and specificity to differentiate normal versus abnormal pelves. These findings may be helpful for clinical cases with equivocal diagnoses and for future development of automated diagnostic tools.

Traumatic stifle injury in 72 cats: a multicentre retrospective study

OBJECTIVES

The aim of the study was to describe traumatic stifle injury in cats and report complications and long-term outcome.

METHODS

The medical records from seven veterinary hospitals of cats treated for traumatic stifle injury were reviewed. Long-term follow-up data were collected from referring veterinarians and using the Feline Musculoskeletal Pain Index, collected from owners.

RESULTS

Seventy-two cats were included in the study. The most common combination of ligament injury involved both cruciate ligaments and the lateral collateral ligament (25.4%). Medial meniscal injury was more common (66.2%) than lateral meniscal injury (59.4%). A temporary transarticular pin was used intraoperatively to aid reduction in 23/73 (31.5%) surgeries. Postoperative immobilisation was applied in 41/72 (56.9%) cats with a mean duration of 4.8 weeks. Short-term complications occurred in 40/64 (62.5%) cats. Long-term complications occurred in seven (17.5%) cats. Overall outcome was excellent in 25/61 (41%) cats, good in 13/61 (21.3%) cats, fair in 11/61 (18%) cats and poor in 12/61 (19.7%) cats. Mean length of follow-up was 29.6 months (range 0.5-204). A significantly poorer outcome was observed in cats with medial meniscal injury and those undergoing revision surgery. Use of a transarticular pin when left in situ for postoperative immobilisation was associated with a poorer outcome (P = 0.043) and a higher risk of complications (P = 0.018). Postoperative immobilisation was not related to outcome.

CONCLUSIONS AND RELEVANCE

Traumatic stifle injury in cats can lead to rupture of multiple ligaments causing significant instability of the joint. Surgical treatment is associated with a high rate of short-term complications, although long-term outcome may still be good to excellent in the majority of cats (62.3%). In cats where follow-up was available, postoperative immobilisation had no positive effect on outcome and may not be required. Leaving a transarticular pin for postoperative immobilisation is not recommended as it was significantly associated with a poorer outcome and a higher complication rate.

Characterization by immunocytochemistry of ionic channels in Helix aspersa suboesophageal brain ganglia neurons

The aim of this work was to characterize several ionic channels in nervous cells of the suboesophageal visceral, left and right parietal, and left and right pleural brain ganglia complex of the snail Helix aspersa by immunocytochemistry. We have studied the immunostaining reaction for a wide panel of eleven polyclonal antibodies raised against mammal antigens as follows: voltage-gated-Na+ channel; voltage-gated-delayed-rectifier-K+ channel; SK2-small-conductance-Ca2+-dependent-K+ channel apamin sensitive; SK3 potassium channel; charybdotoxin-sensitive voltage-dependent potassium channel; BKCa-maxi-conductance-Ca2+-dependent-K+ channel; hyperpolarization-activated cyclic nucleotide-gated potassium channel 4; G-protein-activated inwardly rectifying potassium channel GIRK2 and voltage-gated-calcium of L, N and P/Q type channels. Our results show positive reaction in neurons, but neither in glia cells nor in processes in the Helix suboesophageal ganglia. Our results suggest the occurrence of molecules in Helix neurons sharing antigenic determinants with mammal ionic channels. The reaction density and distribution of immunoreactive staining within neurons is specific for each one of the antisera tested. The studies of co-localization of immunoreaction, on alternate serial sections of the anterior right parietal ganglion, have shown for several recognized mapped neurons that they can simultaneously be expressed among two and seven different ionic protein channels. These results are considered a key structural support for the interpretation of Helix aspersa neuron electrophysiological activity.

Localization of connexins in neurons and glia cells of the Helix aspersa suboesophageal brain ganglia by immunocytochemistry

The aim of the present study was to examine the distribution of cells expressing connexin 26 (Cx26) in the suboesophageal visceral, left and right parietal and left and right pleural ganglia of the snail Helix aspersa by immunocytochemistry. Altogether we have found approximately 452 immunoreactive neurons which represent the 4.7% of the total neurons counted. The stained large neurons (measured diameter 55-140 microm) occurred mostly on the peripheral surface of the ganglia while the small immunostained cells (5-25 microm diameter) were observed in groups near the neuropil. The number of large neurons giving positive Cx26-like immunostaining was small in comparison with that for medium (30-50 microm diameter) and small sized cells. The expression of Cx26 was also observed in the processes of glia cells localized among neurons somata and in the neuropil showing that the antiserum recognized epitopes in both protoplasmic and fibrous glia cells of Helix aspersa. The neuropils of all ganglia showed fibers densely immunostained. While we have observed a good specificity for Cx26-antiserum in neurons, a lack of reaction for Cx43 antiserum was observed in neurons and glia cells. The reaction for enolase antiserum in neurons was light and non-specific and a lack of reaction in glia cells and processes for GFAP antiserum was observed. Although the percentage of positive neurons for Cx26 antiserum was low is suggested that in normal physiological conditions or under stimulation the expression of connexin could be increased. The observed results can be considered of interest in the interpretation of Helix aspersa elemental two neuron networks synchronizing activity, observed under applied extremely low frequency magnetic fields.

S-100 protein immunoreactivity in the upper eyelid of the sheep Ovis aries

The aim of this work was to analyse the distribution pattern of S-100-immunoreactive elements in the upper eyelid of the sheep. This pattern may be of importance regarding the diagnosis and prognosis of eyelid tumours that are linked to deregulation of S-100 gene expression. Thirty upper eyelids taken from 15 adult male Ovis aries were studied by means of the peroxidase-antiperoxidase method for light microscopy. S-100-immunopositive cells were found in the eyelid edge. S-100-immunopositive steams and thinner fibres were found throughout the eyelid. These nerve processes typically were denser around glands, hair follicles and blood vessels. S-100-immunopositive elements may play a role as neuromodulator and also in the development of the vegetative innervation of the epithelium and its derivatives.

Location of zinc and 65Zn in spinal ganglia of the rat

Following the works of Velazquez et al. (1999), Jo-Seung et al. (2000), Wang et al. (2001), Danscher et al. (2001) and the criteria of Zinc-containing neurons established by Frederickson et al.(2000), we have found the presence and localisation of Zinc in the neurons of the dorsal root ganglia of Wistar rat, by using Timm's thecnique and by studying the autoradiographic uptake of 65Zn. The agreement between the results of both techniques allows us to classify these spinal ganglion neurons as Zinc-containing neurons and also, to confirm some of the results of Velazquez et al. (1999).

65Zn uptake in the rat cerebellum and brainstem

We have studied the autoradiographic uptake of 65Zn in the cerebellum and brainstem of the rat, contrasting these results with Timm's positivity in these structures. Both, autoradiographic uptake and histochemical positivity, have demonstrated Zinc in a location that could be accepted as in climbing fibres and glomeruli of the cerebellum cortex, and also in brainstem neurons that project their axons to the cerebellum cortex, suggesting a circuit where zinc may act as a neuromodulator.

Enteric plexus and interstitial cells of Cajal: interrelationship in the stomach of Podarcis hispanica (Reptilia). An ultrastructural study

The ultrastructure organization of the stomach enteric plexus was examined in the lizard Podarcis hispanica. The ganglions of the myenteric plexus present a low number of nerve cell bodies with a peculiar nucleus, which occasionally establish direct contacts with cells of the circular muscle layer. Glial cells are smaller than the neurones, and their nucleus is very electron-dense. They surround the axons that constitute the fibres of the myenteric plexus. Four main types of axon profile are described in a morphological consideration of the vesicle population. In the interstice of the circular muscle layer we describe two types of interstitial cells that, due to their ultrastructural characteristics, may be equivalent to the interstitial cells of Cajal which have been described in mammalians. These cells shows parallel distribution to the stomach nerve plexuses, establishing close contacts with them through their long cytoplasmic prolongations. By means of small gap-like unions, they contact both each other and the smooth muscle cells near them. We describe a submucous plexus, where neuronal bodies are scattered among bundles of nervous fibres, some of which are myelinated. A mucous plexus with isolated neurones is located in the lamina propria. Axonal varicosities containing vesicles contact with the cells of the mucous. Interconnected interstitial cells may also be found in this plexus.

Acetylcholinesterase-positive and paraformaldehyde-induced-fluorescence-positive innervation in the upper eyelid of the sheep (Ovis aries)

This is the first study which describes the innervation of some eyelid structures, such as the glands of Moll and the glands of Zeiss. It is also the first to investigate the innervation pattern of the eyelid as a whole. We have studied the acetylcholinesterase-positive and paraformaldehyde-induced-fluorescence-positive (FIF+) innervation pattern of the different structures that constitute the upper eyelid of the sheep. There is widespread acetylcholinesterase-positive innervation in the epithelium, but not such an abundant FIF+ innervation. Both types of innervation are represented in the connective tissue by trunks or fibers that are distributed towards the different structures immersed within them. In the glands of Zeiss, cholinesterase-positive innervation is much more widespread than FIF innervation. On the contrary, the glands of Moll present denser FIF+ innervation than acetylcholinesterase-positive innervation. The Meibomian glands and the lachrymal glands show a rich acetylcholinesterase-positive and FIF+ innervation. Eyelid muscle innervation is mainly acetylcholinesterase-positive. In the conjunctive membrane there is no acetylcholinesterase-positive innervation, and only scarce FIF+ fibers can be demonstrated.

Intrinsic innervation in the intestine of the lizard Podarcis hispanica

The aim of this study was the description of the morphology and distribution of nerve structure elements in the intestine of the lizard Podarcis hispanica using different histochemical methods; namely acetylcholinesterase (AChE), formol-induced fluorescence for catecholamines (FIF), nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d), and immunohistochemistry for vasoactive intestinal peptide (VIP), as well as substance P (SP) and electron microscopy. The AChE method showed fibres in the myenteric and submucosal plexus, with a higher fibre density in the large intestine. The highest number of related neurons was located in the myenteric plexus ganglia. Noradrenergic innervation was distributed through the myenteric and submucosal plexus, and also around blood vessels, with the highest fibre density in the large intestine. VIP immunohistochemistry showed a wide distribution of positive fibres throughout the intestine, although the highest density was again detected in the large intestine. Small positive cells for VIP were located at internodal segments in the plexus. SP labeling, although subtle, was present all along the intestine. It showed delicate varicose nets and few fibres innervating blood vessels. Small positive cells for SP were located in the large intestine. The indirect method to detect nitric oxide (NO)-producing system showed neural cells in the myenteric plexus ganglia of the large intestine. Electron microscopy showed ganglion neurons with scattered chromatin condensations, glial cells with higher electron density, and axons with varicosities occupied by different vesicles. We also identified certain cells as interstitial cells of Cajal due to their ultrastructural features. They were mostly located in the region of the myenteric plexus.

Distribution of NADPH diaphorase-positive neurons in the enteric nervous system of the rabbit intestine

Nitric oxide (NO) has been proposed as an inhibitory transmitter in gastrointestinal muscle relaxation. We analyzed the distribution of nitric-oxide producing neurons in the rabbit intestine through nicotinamide-adenine-dinucleotide-phosphate-diaphorase histochemistry. By this reliable and convenient method, we visualized neuronal nitric-oxide-synthase, the enzyme responsible for nitric oxide generation, in the rabbit intestine. In the ileum and rectum, nitric-oxide-synthase-related diaphorase activity was present in the myenteric plexus ganglion cells, and in the nerve fibers in the internodal strand, secondary, and tertiary plexuses. These fibers were particularly abundant in the deep circular rather than in the outer longitudinal muscle layer. In the inner submucosal plexus, we found scarce labeled neurons. Labeled neural somata showed a range of sizes and shapes suggesting different functional roles. The present basic information is required to use the rabbit as an experimental animal in neurochemical NO enteric research.

Histochemical, immunohistochemical, and electron microscopy study of the caudal portion of the chicken intestinal nerve of Remak

In order to deepen our knowledge of the different components of the chicken intestinal nerve of Remak (I.N.R.), we have studied it by means of histochemical, immunohistochemical and electron microscopy techniques to distinguish the different neurotransmitters. We have found cholinergic cell bodies, as well as acetylcholinesterase (AChE) positive neuronal fibers, forming part of the web that constitutes the I.N.R. in its caudal portion, with a higher density of neuronal bodies in the ganglia. We also observed catecholaminergic neuronal bodies and fibers, located fundamentally in the periphery of the nerve, and a low density of catecholaminergic cell bodies. With respect to the vasoactive intestinal peptide (VIP) and substance P (SP) positive peptidergic innervation, we found more abundant neuronal bodies positive for the V.I.P. than for S.P. Electron microscopy corroborated the results observed under the optic microscope, showing the various types of vesicles containing different neurotransmitters.

Intrinsic innervation of a reptilian esophagus (Podarcis hispanica)

We study the esophagus of Podarcis hispanica through different methods to clarify the structure and affinities of its wall innervation. The acetylcholinesterase method reveals cholinesterase activity in two submucosal nervous plexuses, with an increasing degree of structural complexity in the reptilian esophagus, compared with amphibians. Noradrenergic innervation, detected through fluorescence induced by formol, widely spreads its network in both the myenteric and submucosal plexuses (around the blood vessels in the external submucosal plexus, and to the glandular lamina propria in the inner submucosal plexus). Immunohistochemistry for vasoactive intestinal peptide shows a widespread innervation, with neurons clustered in ganglia and also scattered through the VIPergic network, only at the myenteric plexus. Immunohistochemistry for substance P shows a rich innervation along the entire wall of the esophagus, more concentrated in its caudal region, around the blood vessels. Electron microscopy shows the enteric neuronal ultrastructure and its relationship with the esophagus wall.

Intrinsic innervation of the chicken lower digestive tract

We have studied the different components of the enteric nervous system in the rectum and cloaca of the chicken by means of histochemical and immunohistochemical techniques. We found cholinergic neuronal bodies as well as nervous fibers, which constitute part of the Meissner and Auerbach plexuses. We also observed plentiful catecholaminergic fibers in both plexuses, though there were no catecholaminergic neuronal bodies. With respect to the Vasoactive Intestinal Peptide (VIP) and substance P (SP) positive peptidergic innervation, only positive fibers were found, which were less abundant than in the other zones of the gastrointestinal tract. The optic microscopy results were confirmed by electron microscopy.

The autonomic innervation of the liver and gallbladder of Podarcis hispanica

The innervation of the liver and gallbladder of the lizard Podarcis hispanica has been studied by the following methods: a) demonstration of cholinesterase activity; b) FIF method for catecholamines; and c) immunohistochemistry for VIP. The hepatic parenchyma of the reptile's liver show hepatocytes arranged in regular rows of hepatic cords, the portal triad being typical of higher vertebrates (birds and mammals). Nerve fibers are found in the scarce connective tissue distributed among the hepatocytes. The innervation is restricted to the big branches of blood vessels and biliary ducts. It is represented by cholinergic, noradrenergic and VIPergic fibers. The gallbladder shows a well developed cholinergic plexus with pyramidal cells in the interconnection points of the fiber network. The noradrenergic and VIPergic plexuses are also more widely distributed in the gallbladder than in the liver.

Ultrastructural characteristics of anterior gut innervation of Gallus gallus

The enteric nervous system of the bird's anterior gut is very well developed. Myelin fibres are seen accompanying the nervous trunks up to the mucous layer. Glial cells duplicate the number of neurons in the myenteric plexuses. Their number decreases at the submucous plexuses, but it is always higher than the neurons. Isolated neurons are widely spread in the circular muscle coat accompanying the nervous trunks which can be inter and intrafascicularly located. Direct synaptic contacts with the soma neuronal membranes are very often seen. We have never observed synaptic specializations. The most prominent varicosities either in the peripheric nervous trunk axons or directly laying on the soma membranes are those containing peptidergic or mixed vesicles of cholinergic and peptidergic types. The neurons show big nuclei of different size and shape. Neighbouring smooth muscle cells show abundant caveolae near the nervous elements. Although we have not observed close contacts with glands, thin axon bundles spread near the glandular cells of the mucous layer.

Frog stomach enteric plexuses in culture: isolation, morphological characterization and bioelectrical recordings

We have succeeded in the isolation, culture and morphological characterization of Rana ridibunda stomach enteric plexuses. We have furthermore obtained intra and extracellular bioelectric recordings from the explants in culture. The culture medium used (Eagle MEM), the collagenase digestion and the general culture conditions followed are similar to those applied to mammal enteric plexus explant cultures. The most striking difference is that the solutions were diluted to 70% in order to maintain the osmolar conditions required by the amphibian cells. Acetylcholinesterase, osmium tetroxide-zinc iodide- and para-formaldehyde-induced fluorescence methods reveal similar morphological images from the perivascular fibre plexuses. The different cell types observed by phase contrast light microscopy from the myenteric explants in culture have been identified by comparison with those revealed by the acetylcholinesterase method. The prevailing neurons show piramidal somas; other neurons are bipolar with oval somas and a third type shows oval somas tightly aligned, following sinusoidal courses. The intra and extracellular bioelectric recordings from the explants in culture show that the culture conditions we have applied preserve the electrophysiological properties of the neuronal membranes. These preliminary recordings will allow us to undertake the synaptic characterization of the gastrointestinal neurotransmitters in frogs.

The autonomic innervation of the liver and gallbladder of Rana ridibunda

1--The innervation of the liver and gallbladder of Rana ridibunda has been studied by the following methods: (a) demonstration of cholinesterase activity; (b) FIF method for catecholamines; (c) immunohistochemistry for VIP and (d) electron microscopy. 2--The hepatocytes are arranged in regular rows of hepatic cords, very little connective tissue is distributed in the parenchyma, the innervation being restricted to the big branches of blood vessels. 3--Well defined cholinergic and adrenergic plexuses surround the hepatic arteries, portal veins and biliary ducts. The VIPergic innervation is scarce in the liver but a richly branched plexus spreads in the wall of the gallbladder. 4--Cholinesterase-positive cells are widely distributed accompanying the nerve trunks of the gallbladder. The innervation distribution is prominent in the portion of the gallbladder next to the hepatic hilus. 5--A population of melanin-storing cells besides free melanin granules are present in the liver parenchyma and are prominent in the gallbladder where the melanocytes are disposed in close contact with blood vessels and nerve structures. We have observed that the number of these visceral melanocytes considerably increases in winter, particularly in the liver.

Intrinsic and extrinsic innervation of the amphibians esophagic myenteric plexuses

The innervation of Rana ridibunda esophagus myenteric plexuses has been studied by the following methods: demonstration of cholinesterase activity; FIF method for catecholamines; immunohistochemistry for VIP, SP and SOM, and conventional electron microscopy. The cholinergic innervation is important in the esophagus wall where, in addition to the well known extrinsic component, there is a rich intrinsic plexus with cells and fibres widely distributed. The esophagus, together with the intestine, are the Rana gut portions where the adrenergic component is more broadly expressed. The adrenergic innervation seems to be almost entirely of extrinsic origin. We have shown that, for the tested peptides, there is an intrinsic innervation represented by VIP, SP and SOM like plexuses. We do not discard nonetheless an extrinsic component. The ultrastructure reveals the morphological characteristics of the enteric neurons as well as the fine inter-relationships between the nervous elements and the functional components of the esophagic wall.