The nervous system in horses is a complex network responsible for transmitting signals between different parts of the body. It consists of the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which comprises nerves that extend throughout the body. The nervous system regulates various physiological processes, including movement, sensation, and the coordination of bodily functions. It plays a critical role in processing sensory information and initiating appropriate responses. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of the equine nervous system, including its role in behavior, response to stimuli, and neurological disorders.
Brown MP, Embertson RM, Gronwall RR, Beal C, Mayhew IG, Curry SH.Six mares were given 5 IM injections (at 12-hour intervals between doses) of amikacin sulfate at a dosage of 7 mg/kg of body weight. Serum amikacin concentrations were measured serially throughout the study; synovial, peritoneal, endometrial, and urine concentrations were determined after the last injection. Amikacin concentrations of the CSF were measured serially in 3 of the 6 mares; 1 of the 3 mares had septic meningitis. Mean serum amikacin concentrations peaked at 1 to 2 hours after IM injection. The highest mean serum concentration was 19.2 micrograms/ml (1.5 hours after the 5th injectio...
Adams R, Mayhew IG.Behaviour and response to neurological testing of apparently healthy newborn foals differed significantly from the adult in several ways. Foals responded to external stimulation with exaggerated movements although they tended to sink into a relaxed state when restrained. They had a more angular head position and assumed a base wide stance. The menace reflex developed during the first two weeks post partum. In general, the foals' gait was choppy or dysmetric. In lateral recumbency the foals had increased extensor tone, hyperreflexive tendon reflexes, crossed extensor reflexes as well as recumbe...
Rousseaux CG, Futcher KG, Clark EG, Naylor JM.Two cases of cauda equina neuritis are compared and contrasted. Neurological deficits of the tail and perineum were noted and functional deficits were seen in gait, urination, defecation and cranial nerve function. Lesions consisted of nonsuppurative inflammation of the nerve trunks and proliferation of the perineurium of the cauda equina. Cranial nerve involvement in one case supported a diagnosis of polyneuritis equi rather than cauda equina neuritis. The possible etiologies and pathogenesis of this disease are discussed.
Erickson HH, Kitchell RL.In the last 2 decades there have been substantial advances in our knowledge of the scientific basis of the mechanisms of pain. Nociceptors or pain receptors are widespread in the skin and tissues of animals; chemical mediation of nociceptor excitation may provide a key for understanding the peripheral phenomena related to pain. The expression of pain in animals involves multiple ascending and descending branches, as well as specialized pain-signaling mechanisms in the spinal cord. The importance of these different pathways varies with species and circumstances. Endogenous neural systems in the...
Mayhew IG.Arthrogryposis multiplex congenita was studied in a newborn thoroughbred foal. The syndrome affected only the left hind limb allowing the right hind limb to serve as a reference. There was a significant depletion of large motor neurons from the ventral horn of the spinal cord from L3 to S4 on the affected side. Hypoplasia of nerves, muscles, and bones was present in the affected limb. Histologically, hypoplasia and degeneration of myofibers and nerve bundles were seen. No cause of the syndrome, which corresponds to most human cases, was determined. Neuromuscular arthrogryposis was diagnosed be...
Sławomirski J, Flieger S, Jastrzebski M, Boratyński Z.The studies carried out on 2 spinal cords of horses showed that cells of the medial motor nucleus (nucleus motorius medialis) are present in all neuromers of the lumbar and sacral segment of the spinal cord. It lies in the medial part of grey matter of the ventral column, neighbouring laterally and ventrally with cells of the lateral motor nucleus, whereas dorsally with cells of the nucleus of the ventral commissural horn. Along the nucleus numerous constrictions and intervals are found, which are connected with various numbers of nerve cells in particular cross-sections.
Flieger S, Sławomirski J, Boratyński Z, Jastrzebski M.Two medullae oblongatae of horses were cut into 15 microns cross-sections and stained according to the modified method of Nissel. The lateral motor nucleus lies in the lateral and median part of the ventral column of spinal cord grey matter. It adjoins medially nucleus motorius medialis of the spinal ventral column. Cells of this nucleus occur both along the whole lumbar and sacral segment of the spinal cord. In the lateral motor nucleus three cell groups are distinguished-median, basal and lateral. The latter is divided in some segments into subgroups-dorsal and ventral. Along the nucleus qui...
Liu SK, Dolensek EP, Adams CR, Tappe JP.Degenerative myelopathy was diagnosed in six Mongolian wild horses. Three of the horses had a history of ataxia dating from birth to 3 months of age. The clinical signs were uncoordinated movement of the hindlimbs and an abnormally wide-based gait and stance. The other 3 horses had mild ataxia. There were no gross lesions in the brain, vertebrae, or spinal cord. Histologic examination revealed degeneration of the neural processes in the ventral and lateral funiculi of all 6 horses. Myelin sheaths were dilated and vacuolated, and there were swollen, fragmented, or lysed axons. Neuronal degenera...
Power HT, Watrous BJ, de Lahunta A.In 6 horses, clinical signs of illness implicated a lesion involving the facial and vestibulocochlear nerves. One horse had signs of otitis externa. Five horses had radiographic changes primarily involving periosteal bony proliferation of the stylohyoid bone at its articulation with the temporal bone. Five horses improved with antibiotic therapy. Otitis media-interna was found at necropsy of one horse.
Beech J.The cytology of cerebrospinal fluid samples from horses is described. The samples were obtained from 24 normal horses, 35 horses with axonal degeneration and/or spinal cord compression, 29 horses with encephalomyelitis, 14 horses with other lesions of the nervous system, and eight horses with signs of neurologic dysfunction of undetermined origin. (Three of the latter were suspected botulinum intoxications.) Fluid was aspirated from the atlanto-occipital space following general anesthesia or immediately after a lethal dose of barbiturate. In two horses, fluid also was aspirated from the lumbos...
London WT, Levitt NH, Altshuler G, Curfman BL, Kent SG, Palmer AE, Sever JL, Houff SA.Fetal rhesus monkeys were inoculated intracerebrally with an attenuated strain of western equine encephalitis virus. All animals developed microcephaly. Twelve of sixteen monkeys developed ex vacuo hydrocephalus. All virus inoculated fetuses developed WEE virus antibody. Virus could not be recovered at the time of delivery. Monkeys with the highest WEE antibody titers showed the greatest degree of hydrocephalus.
King JM, Roth L, Haschek WM.Focal myocardial necrosis secondary to neural lesions was diagnosed in 2 dogs and 1 horse. In each case, the neural lesions were traumatic in origin. Spinal cord injury was evident in 1 dog; brain damage was evident in the other dog and presumably in the horse. Retrospective analysis of necropsy material showed that many species were affected, without apparent age or sex predisposition. Central nervous system injury resulting from trauma, infection or space-occupying lesions was associated with acute myocardial necrosis in all cases. The myocardial necrosis was rarely fatal; however, it did ca...
Sweasey D, Patterson DS, Leadon DP.The lipid content of spinal cord, expressed as a percentage of adult values, was considerably higher for newborn foals than for several other species and traces of esterified cholesterol (type A) were only rarely present in horse fetal cord (from 270 days gestational age onwards). This suggested that, at birth, the spinal cord is neurochemically more 'mature' in the horse than in cattle, sheep and pigs. Data for premature foals revealed no lipid abnormality suggestive of myelin immaturity or degeneration.
Mayhew IG.A technique for the subarachnoid perfusion-fixation of the central nervous system was developed to help identify various significant vascular accidents (SVAs) in the central nervous system (CNS) of 24 neonatal foals submitted for necropsy. SVAs, comprising subarachnoid, parenchymal and nerve root haemorrhages, and oedema and necrosis, occurred in 17 foals, more frequently in the spinal cord than the brain. They occurred as frequently in premature foals as in those born at full term, in foals born dead as in foals born alive, and in foals born following dystocia with an assisted delivery as in ...
Thein P.During the last 2 years different equine herpesviruses serotype 1 strains have been isolated from cases of paretic or paralytic disease among horses in the Federal Republic of Germany. In this paper the available information is collated and briefly reviewed. A short description of the symptoms and the possible mechanism of the pathogenesis are given.
Chen CL, Riley AM.Serum thyroxine (T-4) and triiodothyronine (T-3) concentrations were assayed in neonatal foals (1.5 to 4 months) and mature horses (2 to 25 years old) by a modified radioimmunoassay procedure. Blood was collected from 52 clinically healthy foals and horses of various breeds (Thoroughbreds, Quarter Horses, American Saddle Horses, and a single cross-bred horse). Neonatal foals had high serum concentrations of T-4 (mean, 4.02 microgram/dl) and T-3 (192.9 ng/dl) as compared with the values in mature horses (T-4, mean of 1.76 microgram/dl; T-3, mean of 98.69 ng/dl). Stallions had slightly higher T-...
Clark EG, Townsend HG, McKenzie NT.Two cases of nonsuppurative myeloencephalitis are reported which clinically and pathologically resemble equine protozoal myeloencephalitis. Lesions in both horses were associated with Toxoplasma-like organisms visible in microscopic sections. Clinical signs and lesions in one case primarily involved the brain and in the other case principally involved the spinal cord and associated meninges. Positive identification of the organisms was not achieved; however, the etiological agent is unlikely to be a species of Toxoplasma. Recently published studies suggest a species of Sarcocystis is involved....
Dal Canto MC, Rabinowitz SG.Arboviruses are important pathogens for both animals and humans. Venezuelan equine encephalomyelitis virus (VEEV) is an arbovirus whose pathogenicity for grey matter structures has been previously studied. To our knowledge, the present study is the first to describe extensive inflammation and demyelination in spinal cord white matter of mice infected with VEEV. To probe a possible immunepathogenesis of white matter alterations in this infection, nude mice and heterozygous controls were similarly infected. Whereas controls still showed inflammatory demyelination, nude mice showed no white matte...
Baker JR, Ellis CE.The causes of death recorded in 480 consecutive post mortem examinations of horses performed at the department of pathology, Veterinary Field Station, University of Liverpool, between February 1958 and February 1980, are reported. The alimentary, locomotor and nervous systems were those most frequently diseased. The most common specific entities were those associated with grass sickness, fractures and endoparasitism.
Tate LP, Evans LH.Cryoneurectomy was performed experimentally on 10 digital plantar nerves of normal horses. All nerves were frozen to -30 C, using a double freeze-thaw cycle. Nerves were harvested at 10 days and at 4, 12, 16, and 24 weeks and were examined histologically for evidence of regeneration. The terminal portion of the transected nerves treated with cryosurgery did not have any signs of regeneration or neuroma formation at these periods. Cryoneurectomy was performed on 101 nerves of 32 horses with diseases requiring neurectomy. Twenty-seven of these nerves had been subjected to previous neurectomy, an...
The Journal of protozoologyAugust 1, 1980
Volume 27, Issue 3 288-292 doi: 10.1111/j.1550-7408.1980.tb04259.x
Simpson CF, Mayhew IG.Equine protozoal myeloencephalitis (EPM) was diagnosed in 10 horses. By electron microscopy, schizonts were found in intact host cells of the spinal cords or, more frequently, free in the extracellular spaces. Developmental stages of schizonts differed morphologically, and the late stage of schizogony was characterized by endopolygeny. These findings permitted tentative identification of the protozoon as a Sarcocystis sp. Free merozoites were present in the extracellular spaces or in cells of the spinal cord. Pericytes of capillaries were most frequently parasitized by merozoites were present ...
Greet TR, Jeffcott LB, Whitwell KE, Cook WR.The paper describes the assessment and practical implications of a laryngeal adductory reflex in a series of 30 ataxic and 64 non-ataxic horses. The reflex was evoked by slapping the saddle region just caudal to the withers. In normal horses this produced a flickering adductory movement of the contralateral arytenoid cartilage which was observed endoscopically. Abolition of the laryngeal response was encountered in in 3 situations:--(1) Disruption of the afferent impulse occurred in those horses in which there was significant spinal cord pathology affecting the pathway from the cranial thoraci...
Henry RW, Diesem CD, Wiechers DO.Eleven ponies and 13 horses were used to develop a technique for determining conduction velocity for the radial and median nerves and establishing normal limits for these values. One pony was euthanatized to determine the course of the radial and the median nerves. From this dissection, both proximal and distal stimulation sites for the radial and the median nerves were selected, as well as areas for recording muscle evoked responses from the abductor digiti I longus (extensor carpi obliquus) and the radial head of the deep digital flexor muscles. The other ten ponies and the horses were used ...
Bergeler J, Liske-Schmitz A, Schmitz T, de Camp NV.The First Night Effect is a phenomenon whereby sleep duration and quality are compromised in unfamiliar environments or situations. Horses are often transported to new locations, such as sporting events. We wanted to know if the First Night Effect is also detectable in horses in two different populations. To investigate this, we compared five horses from a professional sports horse barn that are regularly used in competitions, with six horses from a breeding barn, that are less frequently transferred to unfamiliar places. Despite the significant differences observed in electroencephalography (...
Thein P, Brown K.Infections with EHV1 can lead to manifestation at the CNS of horses followed by encephalomyelitis and "equine stroke". Horse experiments could confirm the clinical picture and gave links to the potential pathogenesis of the disease. We also have been in the position to isolate and characterize an EHV4 virus out of the brain of a horse with CNS disorders. The two viruses carry different biological properties which obviously dominate the pathogenesis. These properties as well as experimental and field cases are described and different diagnostic tests are discussed.
Journée HL, Journée SL.Depending on the localization of the lesion, spinal cord ataxia is the most common type of ataxia in horses. Most prevalent diagnoses include cervical vertebral stenotic myelopathy (CVSM), equine protozoal myeloencephalitis (EPM), trauma and equine degenerative myeloencephalopathy (EDM). Other causes of ataxia and weakness are associated with infectious causes, trauma and neoplasia. A neurologic examination is indispensable to identify the type of ataxia. In addition, clinical neurophysiology offers tools to locate functional abnormalities in the central and peripheral nervous system. Clinical...
Henker LC, Lorenzett MP, Piva MM, Wronski JG, de Andrade DGA, Borges AS, Driemeier D, Oliveira-Filho JP, Pavarini SP.Holoprosencephaly is a central nervous system malformation, characterized by incomplete or total lack of division of prosencephalon hemispheres, which is commonly accompanied by craniofacial malformations. A 9-month-gestation aborted American Quarter Horse fetus was submitted for postmortem examination. The fetus lacked haircoat and had severe facial malformations including marked shortening/absence of the maxillary, incisive and nasal bones, bilateral anophthalmia, and pre-maxillary agenesis. The prosencephalon was small and nearly spherical, represented by a single lobe, with no visible sepa...
Rojas-Núñez I, Gomez AM, Palmer S, Mohammed HO.Neurofilaments are structural proteins that are concentrated in the body and axons of neurons. Damage to the neurons or axons as a result of trauma or infectious diseases leads to the release of neurofilaments into blood and cerebrospinal fluid (CSF). This case-control study was carried out to compare serum levels of phosphorylated neurofilament heavy chain (pNF-H) between clinically healthy Thoroughbred (TB) horses and TB horses that suffered catastrophic musculoskeletal injuries (cMSI), and to investigate the correlation between putative risk factors and serum concentrations of pNF-H in inju...
Bolat D, Yıldız D, Bahar S, Yürüker S, Kaymaz F, Ilgın C, Bozkurt EÜ, Karahan S, Sabancı SS.We investigated the microscopic structure of transverse sections of the oculomotor, trochlear and abducens nerves of Arabian foals using stereological methods. Bilateral nerve pairs from 2-month-old female Arabian foals were analyzed. The tissues were embedded in plastic blocks, then 1 µm thick sections were cut and stained with osmium tetroxide and methylene blue-azure II. Stereology was performed using light microscopy. Morphometry showed that the right and left pairs of nerves were similar. The transverse sectional areas of the oculomotor, trochlear and abducens nerves were 1.93 ± 0.19 mm...
Sakurai M, Isshiki S, Sasaki N, Sakai Y, Yamada Y, Morimoto M.A 7-year-old male Thoroughbred horse exhibited recurrent falls followed by convulsive seizures. The horse was clinically diagnosed with epilepsy and phenobarbital treatment was initiated. However, as seizure control was unsuccessful, the animal was euthanized. At necropsy, yellow-brown linear lesions were found extensively at the U-fibres and cingulate gyrus within the cerebral white matter. Histopathologically, linear demyelination and occasional cavitation were observed. Glial cells with yellow-brown pigment granules, which were autofluorescent, positive to the periodic acid-Schiff reaction ...
Bowker RM, Rockershouser SJ, Vex KB, Sonea IM, Caron JP, Kotyk R.To determine whether the distal interphalangeal (DIP) joint directly or indirectly communicates with the navicular bursa (bursa podotrochlearis) and to identify sensory nerves in these synovial structures that might be desensitized by intra-articular injections of anesthetics, Evans blue dye in physiologic saline solution, Luxol fast blue dye with mepivicaine, or commercial latex was injected into the DIP joint (5 ml) or the navicular bursa (3 ml) of 152 digits obtained from horses or ponies at necropsy. The digits were frozen, cut with a band saw, and examined for distribution of dye or latex...
Furr MO.Neurologic disease of foals is a diagnostic and therapeutic challenge for veterinarians. Disease conditions such as neonatal encephalopathy are seen as well as developmental and congenital defects, bacterial infections, and trauma. Neonatal encephalopathy can be considered a "syndrome" with a variety of causes resulting in a similar clinical presentation. These causes can be categorized as maladaptation, hypoxic/ischemic encephalopathy, and metabolic abnormalities, all leading to signs of cerebral and brainstem disease. Spinal cord signs may occasionally be seen, but these signs are usually ov...
Rakestraw PC, Snyder JR, Sanders KM, Shuttleworth WC.To evaluate electrical activity of jejunal circular muscle in horses and characterize electrical responses to stimulation by intrinsic inhibitory neurons. Methods: Portions of jejunum obtained from horses euthanatized for reasons other than gastrointestinal tract disease. Methods: Isolated circular muscle preparations were perfused with oxygenated modified Krebs solution. Glass microelectrodes were used for intracellular recording of membrane potentials from single smooth muscle cells. Electrical activity and responses to electrical field stimulation (EFS) of intrinsic neurons in the presence ...
Rasbech NO.Ejaculatory disorders of the stallion seem to occur more frequently than hitherto accepted. The condition is manifested differently in individual stallions from normal copulation without ejaculation to an abnormal pattern of copulation without or with occasional ejaculation. The condition is probably caused by a functional disturbance of the nervous mechanism which controls the ejaculatory process, and may be caused by environmental or other factors. Eleven cases of ejaculatory disorders in normal healthy stallions were investigated and three of these animals recovered after simple correction ...
Domange C, Casteignau A, Collignon G, Pumarola M, Priymenko N.Seventy horses with clinical evidence of Australian stringhalt were studied in France from 2003 to 2008. All horses but one had history of bilateral stringhalt and grazed pastures infested with Hypochoeris radicata (L.). They displayed hind limbs hyperflexion and an abnormal gait because of a distal axonopathy with a skeletal muscle denervation and atrophy. Fifty percentage of them recovered spontaneously in 8 months, and only the more affected horses were unable to recover even if they looked healthy on dry and hot days. Clinical troubles revealed also depression or aggressive behaviour, sugg...
Ciosek J, Kimes A, Vinardell T, Miller DC, Antczak DF, Brooks S.Valued for their temperament, beauty, athletic ability, and exhibition in the show ring, Arabian horses are an important component of the horse industry. Juvenile idiopathic epilepsy (JIE), a seizure disorder, is most often reported in Arabian foals from birth to 6 months of age. Affected foals exhibit tonic-clonic seizures lasting as long as 5 min and risking secondary complications like temporary blindness and disorientation. Some foals outgrow this condition, while others die or suffer lifelong complications if not treated. Previous work suggested a strong genetic component to JIE and propo...
Louie EW, Streeter R, Story M, Scrivani PV, Barrett M, Mullen KR.A neonatal Dutch Warmblood colt was evaluated for inability to stand, incoordination and intention tremor. Despite partial improvement in clinical signs during the first 4 days of hospitalization, neurological deficits remained. Magnetic resonance imaging identified a unilateral infratentorial arachnoid cyst-like lesion with ipsilateral compression and displacement of the cerebellar hemisphere, absent corpus collosum, polymicrogyria, suspect leukoencephalopathy, and noncompressive occipitoatlantal malformation. Improvement in clinical signs during the first 6 months of life suggests that ho...
Palmieri G, Panu R, Asole A, Farina V, Sanna L.The various types of sensory nerve endings found in the peroneus tertius muscle in the ass and in the horse have been studied with Ruffini's gold chloride method. Free nerve endings have been described as well as encapsulated receptors. These corpuscles are classified as Pacini-like, Ruffini's terminations and also Golgi's tendon-organs. The authors have pointed out the morphology, topography and structural characteristics of the above named nervous terminations and have hypothesized that a probable functional relation existed between these nervous corpuscles and the considered tendinous struc...
Galeano R, Germanà A, Abbate F, Calvo D, Naves FJ, Hidaka H, Germanà G, Vega JA.Neurocalcin (NC) is a recently characterized EF-hand calcium-binding protein present in a discrete population of sensory neurons and their peripheral mechanoreceptors, but its presence in peripheral nervous system neurons other than in the rat is still unknown. The present study was designed to investigate the occurrence of NC in the dorsal root ganglia (DRG) of several mammalian species (horse, buffalo, cow, sheep, pig, dog, and rat), including humans. DRG were fixed, embedded in paraffin, and processed for immunohistochemistry using a polyclonal antibody against NC. The size of the immunorea...
Gill KK, Kroeger EA.Equine airway smooth muscle is innervated by vagal efferents and, in addition, displays spontaneous mechanical activity. The preparation thus appears to contain at least two discrete excitable components, the cholinergic neural elements and the smooth muscle membrane. Indomethacin (INDO), a cyclooxygenase (CO) inhibitor, exerts a considerable potentiation of function in this preparation. The latter may be effected indirectly, through loss of the inhibitory effect of endogenous prostaglandin E2 (PGE2) on neural acetylcholine release and through direct effects on smooth muscle of the generally a...
Tennent-Brown BS, Morrice AV, Reed S.Neonatal encephalopathy is the most common neurologic condition affecting newborn foals and shares similarities with perinatal asphyxia syndrome of human infants. In many cases of neonatal encephalopathy there is no obvious episode of acute or chronic hypoxia and other mechanisms likely play a role in the pathogenesis. Increased concentrations of neuroactive progestagens are found in affected foals; whether these molecules are protective, as has been suggested, or play a role in the pathogenesis is unknown. Neurologic diseases other than neonatal encephalopathy affect foals occasionally and sh...
Boratyński Z, Flieger S, Eustachiewicz R, Sławomirski J.In this paper, structure and position of the centers of the parasympathetic nervous system in the horse spinal cord were presented. Studies were carried out on 2 horse spinal cordis. After sampling, the material was dehydrated in alcohol, embedded in paraffin and cut into 15 micron thick sections. The sections were stained according to Nissl's method. Every third section was studied. Nucleus intermediomedialis in the horse spinal cord is an intermittent tract of nervous cells passing from the I cervical neuromere to the V sacral segment. The cells of this nucleus form round, horizontally--oval...
Wright JA, Fordyce P, Edington N.Ultrastructural lesions of the cranial nerves and their ganglia and the autonomic nervous system from 5 cases of neuritis of the cauda equina in the horse are described. They include lysosomal inclusions within the semilunar, geniculate and sympathetic chain ganglia, granulomatous involvement of the coeliaco-mesenteric ganglion and accumulation of axonal organelles in unmyelinated fibres of the great splanchnic nerve, sympathetic chain and oesophageal vagus.
Nasu T, Sueishi A, Morimoto M.We used immunohistochemical techniques to analyze the localization and distribution of the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH) and the neuropeptides methionine-endephalin (M-Enk), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), calretinin (Cal), calcitonin gene-related peptide (CGRP), substance P (SP), and galanin (Gal) in the stellate ganglia of two species of domestic animal (cattle and horses). NPY, VIP and Gal immunoreactive neurons (both cell body and nerve fiber) were observed in the stellate ganglia of both animals. M-Enk and CGRP immunoreactive ne...
Peters M, Graf G, Pohlenz J.A 14-year-old standardbred mare with clinically suspected acute bronchitis was killed because of rapidly progressing central nervous disturbances. Necropsy revealed systemic granulomatous inflammation and vasculitis involving the lungs, thoracic lymph nodes, ribs, and liver. In the cerebrum there was a severe subacute bilateral encephalitis and malacia predominately affecting the white matter, and vasculitis with perivascular infiltration of lymphocytes, macrophages, and giant cells. A causative infectious agent could not be detected by Ziehl-Neelsen, Grocott, or Giemsa stains, by periodic aci...
Whalen LR, Wheeler DW, LeCouteur RA, Yovich JV, Boggie LC, Grandy JL, Kainer RA.Maximal conduction velocities of compound action potentials evoked by stimuli of 2 times threshold in the caudal cutaneous sural (CCSN) and medial cutaneous antebrachial (MCAN) nerves were determined by averaging potentials evoked and recorded through percutaneous needle electrodes. Mean maximal conduction velocities of compound action potentials were: CCSN = 61.3 +/- 2.0 meters/second (m/s) and MCAN = 56.4 +/- 2.8 m/s. To confirm accuracy of our percutaneous recordings, compound action potentials were recorded through bipolar chlorided silver electrodes from the exposed surfaces of fascicles ...
Koh RB, Harrison TM.Over the past years, the concept of pain management in veterinary medicine has evolved and led to the establishment of a new concept of multimodal approach to pain management, as the current standard of care. The use of multimodal analgesia combining pharmacologic and nonpharmacologic techniques not only helps optimize the quality and efficacy of analgesia but also may prevent the development of chronic or persistent pain. During the past decade, acupuncture has become more popular and evolved into one of the most used forms of integrative medicine interventions and nonpharmacologic therapeuti...
Mello GW, Riet-Correa F, Batista MC, Carvalho CJ, Dias AC, Franklin FL, Silva SM, Dias A.Farmers in the State of Piauí in northeastern Brazil reported nervous signs in ruminants and donkeys after ingestion of Brunfelsia uniflora at the start of the rainy season when the plant is flowering. Leaves of the plant, collected at the start or at the end of the rainy season, were administered in single doses of 5-20 g/kg body weight to 8 sheep and 3 donkeys. Two sheep and 1 donkey that ingested 10 g/kg of the plant in November at the start of the rainy season, when the plant was flowering, developed severe convulsions and diarrhea. One sheep was euthanized and autopsied, and no significa...
Martin-Giménez T, Cruz AM, Barragán A, Montero E, Sanchez PG, Caballero G, Corradini I.Occipital condylar fractures (OCFs) causing delayed onset lower cranial nerve paralysis (LCNPs) are rare. We present a 7-year-old Friesian horse with delayed onset dysphagia caused by vagus nerve (CNX) paralysis and suspicion of glossopharyngeal nerve (CNIX) paralysis developed several days after a minor head injury. Endoscopic examination revealed right laryngeal hemiplegia and intermittent dorsal displacement of the soft palate. An area of submucosal hemorrhage and bulging was appreciated over the dorsal aspect of the medial compartment of the right guttural pouch. Radiological examination o...
Mayhew IG.A technique for the subarachnoid perfusion-fixation of the central nervous system was developed to help identify various significant vascular accidents (SVAs) in the central nervous system (CNS) of 24 neonatal foals submitted for necropsy. SVAs, comprising subarachnoid, parenchymal and nerve root haemorrhages, and oedema and necrosis, occurred in 17 foals, more frequently in the spinal cord than the brain. They occurred as frequently in premature foals as in those born at full term, in foals born dead as in foals born alive, and in foals born following dystocia with an assisted delivery as in ...
Zhang XY, Zhu FX, Robinson NE.To investigate the effects of changes in intracellular cAMP on alpha 2-adrenoceptor (AR)-induced inhibition of airway acetylcholine (ACh) release, we examined the effects of the alpha 2-AR agonist clonidine on electrical field stimulation-evoked ACh release from equine tracheal parasympathetic nerves before and after treatment with 8-bromo-cAMP or forskolin. We also tested whether charybdotoxin (ChTX)- or iberiotoxin (IBTX)-sensitive Ca(2+)-activated K+ channels mediate alpha 2-AR-induced inhibition by examining the effect of clonidine in the absence and presence of ChTX or IBTX on ACh release...
Shrauner B, Blikslager A, Davis J, Campbell N, Law M, Lustgarten M, Prange T.The large size of the adult horse prevents the use of advanced imaging modalities in most areas of the axial skeleton, including the lumbosacral vertebral column. Traditional imaging techniques are frequently unable to pinpoint the underlying pathology in horses with caudal back pain. In man, lumbosacral epiduroscopy is used to diagnose and treat subjects with chronic back and leg pain. This technique may close the diagnostic gap in horses with similar clinical signs. Objective: To evaluate the safety and feasibility of lumbosacral epiduroscopy in the standing adult horse. Methods: Descriptive...
Sonea IM, Bowker RM, Broadstone RV, Robinson NE.The tone of respiratory smooth muscle is largely determined by the input from autonomic nerves. The distribution of adrenergic and selected nonadrenergic, non-cholinergic (NANC) nerves in the normal equine trachealis muscle was investigated using immunohistochemistry. The smooth muscle of the trachealis was found to contain numerous nerves immunoreactive for an enzymatic marker of adrenergic nerves, as well as many nerves immunoreactive for a putative NANC neurotransmitter, peptide histidine isoleucine, a potent bronchodilator. The tissue surrounding the respiratory smooth muscle contained num...
