Morphological reproductive characteristics of testes and fertilization capacity of cryopreserved sperm after the Fukushima accident in raccoon (Procyon lotor).

Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, we have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of racoons from the ex-evacuation zone of the FDNPP accident. The radioactivity of caesium-137 (137 Cs) was measured by gamma-ray spectrometry, and the measured radioactivity concentration was 300-6,630 Bq/kg in the Fukushima raccoons. Notably, normal spermatogenesis was observed in the seminiferous tubules of the testes, with the germinal epithelium composed of a spermatogenic cell lineage with no evident ultrastructural alterations; freeze-thawing sperm penetration ability was confirmed using the interspecific zona pellucida-free mouse oocytes IVF assays. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.

Elliptical Fourier descriptors of outline and morphological analysis in caudal view of foramen magnum of the tropical raccoon (Procyon cancrivorus) (Linnaeus, 1758).

OBJECTIVES: To evaluate sexual-size dimorphism and attempt at categorization of inter-individual shapes of foramen magnum outlines using Fourier descriptors which allow for shape outline evaluations with a resultant specimen character definition. MATERIALS AND METHODS: Individual characterization and quantification of foramen magnum shapes in direct caudal view based on elliptical Fourier technique was applied to 46 tropical raccoon skulls (26 females, 20 males). RESULTS: Incremental number of harmonics demonstrates morphological contributions of such descriptors with their relations to specific anatomical constructions established. The initial harmonics (1st to 3rd) described the general foramen shapes while the second (4th to 12th) demonstrated fine morphological details. Sexual-size dimorphism was observed in females (87.1%) and 91.7% in males, normalization of size produces 75% in females and 83% in males. With respect to foramen magnum dimorphism analysis, the result obtained through elliptic Fourier analysis was comparatively better in detail information of outline contours than earlier classical methods. The first four effective principal components defined 70.63% of its shape properties while the rest (22.51%) constituted fine details of morphology. CONCLUSION: Both size and shape seems important in sexual dimorphisms in this species, this investigation suggest clinical implications, taxonomic and anthropologic perspectives in foramen characterization magnum characterization and further postulates an increased possibility of volume reduction cerebellar protrusion, ontogenic magnum shape irregularities in the sample population with neurologic consequences especially among females.

Morfo-histologia dos pulmões e árvore bronquial de Procyon cancrivorus (Carnivora: Procyonidae) / Morphohistology of the lungs and bronchial tree of the Procyon cancrivorus (Carnivora: Procyonidae)

Nenhuma característica dos seres vivos é tão primordial quanto a respiração, e os pulmões são os principais órgãos do sistema respiratório. Este estudo tem por objetivo descrever os aspectos macroscópicos da traqueia, dos brônquios e dos lobos pulmonares bem como os aspectos microscópicos dos brônquios pulmonares do mão-pelada e compará-los com dados da literatura de estudos realizados com mamíferos silvestres e domésticos. Utilizaram-se três exemplares de Procyon cancrivorus, que foram fixados em solução aquosa de formaldeído a 10%. Os pulmões e a traqueia foram dissecados e fotografados com câmera fotográfica digital (Câmera Sony a200, 10.2mpx). Para a identificação das características microscópicas, foram coletados fragmentos de cada brônquio seguindo as técnicas de rotina histológica. O pulmão do Procyon cancrivorus se divide em quatro lobos direito e dois lobos esquerdo e a traqueia apresenta cerca de 31 a 34 anéis. Os brônquios extrapulmonares se dividem em direito e esquerdo; o direito se subdivide em brônquios lobares cranial, médio, acessório e caudal, e o esquerdo em lobares cranial e caudal, com seus respectivos brônquios segmentares. Microscopicamente, os brônquios apresentam um epitélio prismático pseudoestratificado ciliado com células caliciformes e feixes de fibras de musculatura lisa, placas de cartilagem hialina e fibras elásticas. O conhecimento da morfologia desses órgãos nas espécies silvestres auxilia em estudos descritivos e/ou comparativos entre espécies.

No characteristic of living beings is as primal as breathing, and the lungs are the main organs in the respiratory system. This study aims to describe the macroscopic aspects of the trachea, bronchus and lung lobes and microscopic aspects of the bronchi of raccoon lungs and compare with data from the literature studies performed with wild and domestic mammals. We used three samples of Procyon cancrivorus, which were fixed in aqueous 10% formaldehyde, lungs and trachea were dissected and photographed with a digital camera (Sony a200 Camera, 10.2mpx). For the identification of microscopic characteristics, fragments were collected from each bronchus following routine histological techniques. The Procyon cancrivorus lung is divided into four lobes, with two right and left lobes. The trachea has about 31-34 rings. The extrapulmonary bronchi divides into left and right, where the right is divided into lobar bronchi cranial, middle, accessory and caudal lobes and the left in cranial and caudal, with their respective segmental bronchi. Microscopically the bronchial epithelium has prismatic pseudo-ciliated and goblet cells with bundles of smooth muscle fibers, plates of hyaline cartilage and elastic fibers. Knowledge of the morphology of these organs in wild species helps us in descriptive studies and / or comparisons between species.

Análise microscópica e ultraestrutural das glândulas salivares mandibulares de Procyon cancrivorus / Microscopy and ultrastructural analysis of mandibular salivary glands of Procyon cancrivorus

Devido a importância ecológica dos Procyon cancrivorus, o objetivo deste trabalho foi caracterizar morfologicamente e ultra estruturalmente a glândula salivar mandibular desta espécie. Foram utilizadas 10 pares (direita e esquerda) de glândulas salivares mandibulares de cinco animais adultos. As glândulas salivares mandibulares foram dissecadas e mensuradas com paquímetro de precisão e posteriormente processadas por técnica rotineira de histologia e coradas por HE (hematoxilina e eosina) e Picrossírius. Fragmentos das glândulas foram processados para análise em microscopia eletrônica de varredura (MEV). As glândulas salivares mandibulares direitas e esquerdas de P. cancrivorus apresentaram-se lobuladas, formato ovalado, e posicionadas entre a fossa atlantis e o osso basihyoideum do crânio. Microscopicamente, estas glândulas estavam revestidas por uma cápsula de tecido conjuntivo denso não modelado, a qual adentra a glândula através de septos, dividindo-a em lóbulos. Nos septos de tecido conjuntivo estão presentes vasos sanguíneos e nervos, além de ductos interlobulares excretores. Dentro dos lóbulos das glândulas salivares mandibulares, são encontrados ductos do tipo estriado e intercalar, além de predomínio de ácinos do tipo mucoso. Os resultados permitem concluir que as glândulas salivares mandibulares dos Procyon cancrivorus, seguem o padrão estrutural descrito em outras espécies de mamíferos. No entanto os tipos de ácinos podem variar entre as espécies, sendo, portanto, necessários futuros estudos histoquímicos e de biologia celular para desvendar a importância dessa variação para a espécie aqui estudada, comparando com seu hábito alimentar.

Due to the ecological importance of Procyon cancrivorus, the aim of this study was to characterize morphologically and ultrastructurally the mandibular salivary gland of this specie. We used 10 pairs (right and left) of mandibular salivary glands from five adult animals. The mandibular salivary glands were dissected and measured by precision calipers and later processed by histological routine technique, stained by HE (hematoxylin and eosin) and Picrossirius. Fragments of the glands were processed for analysis by scanning electron microscopy (SEM). The mandibular salivary gland, right and left from P. cancrivorus presents lobulated and oval-shape, and it was positioned between the fossa atlantis and basihyoideum ossis of skull. Microscopically, these glands are lined by a capsule formed by dense irregular connective tissue, which enters into the gland by septa, dividing it into lobules. Into the septa of connective tissue were present blood vessels and nerves, and interlobular excretory ducts. Inside the lobes of the mandibular salivary glands, striatum and intermediate-type ducts are found, and the predominance of mucous acini was observed. The results indicate that the mandibular salivary glands of Procyon cancrivorus, follows the structural pattern described in other mammalian species. However the types of acini may vary among species, and thus further histochemical and cell biology studies are required in order to uncover the significance of this variation for the specie here studied, according with their feeding habit.

Estudo das alterações ante-morte da cavidade oral de mãos-peladas (Procyon cancrivorus) de vida livre e de cativeiro / Study of the ante-mortem changes of the oral cavity of crab-eating raccoon (Procyon cancrivorus) free living and in captivity

A maioria das doenças dos animais de natureza e cativeiro encontra-se associada à proximidade humana, que resulta da fragmentação e degradação do habitat destes animais, no isolamento das espécies e no contato mais próximo entre estes e animais domésticos e o homem. Foram estudados os sincrânios de 104 mãos-peladas (Procyon cancrivorus) por meio de avaliação direta, preenchimento de ficha odontológica veterinária e documentação fotográfica, que relataram anormalidades encontradas, as quais foram classificadas e contabilizadas para fins estatísticos. Os achados deste trabalho aludem que os animais de cativeiro foram mais acometidos com as lesões relacionadas à doença periodontal, como cálculo, reabsorção óssea alveolar, deiscência, fenestração, exposição de furca, além de maloclusão, apinhamento dentário e os níveis mais graves de desgaste dentário. Os animais de vida livre apresentaram mais altos índices de fraturas, perdas dentárias ante-morte e escurecimento dentário, que caracterizam maior trauma dentário, durante o processo alimentar. Pretendeu-se, assim, estabelecer um parâmetro do estado de saúde oral da espécie estudada, sua frequência e se esta apresenta as mesmas enfermidades orais em vida livre e em cativeiro, relacionando a prevalência de afecções orais com características da ecologia da espécie.

Most diseases of animals in nature and captivity is linked to human proximity, resulting from habitat fragmentation and degradation of these animal habitats, the isolation of the species and the close contact between them and domestic animals and manhood. We studied 104 crab-eating raccoons (Procyon cancrivorus) skulls by direct assessment of sheet filling veterinary dental and photographic documentation reporting these abnormalities, which were classified and recorded for statistical purposes. The findings show that the captive animals were most affected with injuries related to periodontal disease, such as calculus, alveolar bone resorption, dehiscence, fenestration, furcation exposure, as well as malocclusion, crowding and severe levels of tooth wear. The free-living animals showed the highest rates of fractures, ante-mortem tooth loss and tooth blackout, which feature larger dental injuries during the feeding process. The intention was therefore to establish a parameter of oral health status of the species studied, their frequency and whether it has the same oral diseases in the wild life and in captivity, relating the prevalence of oral diseases with ecological characteristics of the specie.

Indices using external measurements for assessing fat deposition of adult feral raccoons (Procyon lotor) in Kanagawa Prefecture, Japan.

We examined the use of external measurements and relative fat deposition of adult feral raccoons (Procyon lotor) to develop relative indices of body fat deposition in post-growth feral raccoons. From March 2006 to March 2010, 288 adult raccoon carcasses (110 males, 178 females) collected in Kanagawa Prefecture, Japan, which were determined to be 24 months old, were subjected to external measurements of body weight (BW), girth measurement (GM), and body mass index (BMI). To assess relative body fat deposition, we visually classified abdominal subcutaneous fat into three grades (Visible Fat Index [VFI]: I-III). Significant differences in the means of BW (both sexes:P<0.01), GM (females: P<0.05, males: P<0.01), and BMI (both sexes: P<0.01) were detected between seasons. Notably, the means of BW, GM, and BMI (all, both sexes: P<0.01) differed significantly between VFI grades. However, by discriminant analysis with BW, GM, and BMI as independent variables, we obtained a significant discriminant function (both sexes: P<0.01) for distinguishing VFI I from higher VFI grades, but no significant equation was obtained for distinguishing between VFI II and VFI III. Based on the obtained structure matrix of discriminant analysis, BMI was the most valuable component for the discrimination of VFI grades. Thus, we conclude that BMI is a suitable complementary index for assessing relative body fat deposition of adult feral raccoons in Kanagawa Prefecture and may be generalizable to populations in other areas.

Origem e distribuição anatômica do nervo isquiático de mão-pelada (Procyon cancrivorus) / Origin and anatomical distribution of ischiatic nerve in the crab-eating raccoon (Procyon cancrivorus)

O nervo isquiático é considerado o maior nervo do corpo, pertence tanto ao plexo sacral quanto ao lombossacral em carnívoros, continuando até a extremidade distal do membro pélvico, recebe fiibras dos ramos ventrais do sexto e sétimo nervos lombares e do primeiro nervo sacral. O objetivo do presente estudo é descrever a distribuição do nervo isquiático em mão-pelada (Procyon cancrivorus) e comparar com dados literários de animais domésticos e silvestres. Os animais são procedentes de coleta em rodovias, entre as cidades de Goiânia e Jataí, principalmente na BR 364 ou BR 060. (mortos por acidente) e fiixados em solução aquosa, a 10 por cento de formaldeído. Doados ao Museu de Anatomia Humana e Comparada da UFG (Universidade Federal de Goiás, Campus de Jataí, Proc.CAJ-287/2008). As dissecações e documentação fotográfiica permitiram observar a distribuição do nervo isquiático. O nervo isquiático de mão-pelada inerva o membro pélvico passando entre os músculos glúteo médio e profundo, emitindo ramos para a musculatura da região glútea e da coxa, respectivamente, para os músculos glúteo médio, glúteo bíceps, semimembranáceo, semitendíneo, bíceps femoral, gêmeos, quadrado femoral e adutor magno, emitindo nervo cutâneo lateral e caudal da sura para suprir a pele na superfiície lateral e caudal da perna, respectivamente. Próximo ao meio da coxa bifurca-se em nervo tibial e nervo fiibular comum. O conhecimento anatômico da origem e distribuição do nervo is quiático em mão pelada quando comparado com animais domésticos, silvestres e de fazenda, mostram um padrão de inervação semelhante entre os espécimes.

The ischiatic nerve is the largest nerve in the body, belongs both to the sacral and lumbosacral plexus in carnivores, continuing until the distal hind limb, and receives fibers from the ventral branch of the sixth and seventh lumbar nerves and the first sacral nerve. We aim to describe the distribution of the sciatic nerve in raccoon (Procyon cancrivorus) and compare with data of literary domestic and wild animals. The animals are coming to collect on highways (killed by accident) and subjected to fixation in aqueous solution, 10 percent formaldehyde. The dissection and photographic documentation (Sony α200 camera, 10.2mpx) shows the distribution of the sciatic nerve. The ischiatic nerve of raccoon innervates the hind limb passing between the middle and deep gluteal muscles, giving off branches to the muscles of the buttock and thigh, respectively, for the gluteus medius, gluteus biceps, semimembranosus, semitendinosus, biceps femoris, twins, quadratus femoris and adductor magnus, sending the lateral cutaneous nerve of the thickness and flow to supply the skin on the lateral surface of the leg and tail, respectively. Near the middle of the thigh nerve bifurcates into the tibial and peroneal nerve. The anatomical knowledge of the pattern of nervous raccoon (Procyon cancrivorus) is of fundamental importance in research to refer to the distribution of the ischiatic nerve, and show no disagreement with the corresponding data in the literature of domestic carnivores.

Light and scanning electron microscopic study on the tongue and lingual papillae of the common raccoon, Procyon lotor.

We observed the external surface and connective tissue cores (CTCs), after exfoliation of the epithelium of the lingual papillae (filiform, fungiform, foliate and vallate papillae) of the common raccoon (Procyon lotor) using scanning electron microscopy and light microscopy. The tongue was elongated and their two-third width was almost fixed. Numerous filiform papillae were distributed along the anterior two-thirds of the tongue and fungiform papillae were distributed between the filiform papillae. Eight vallate papillae that had a weak circumferential ridge were distributed in a V-shape in the posterior part of the tongue and numerous taste buds were observable in the circumferential furrows of vallate papillae. Weak fold-like foliate papillae were observable at the lateral edge in the posterior part of the tongue and a few salivary duct orifices were observable beneath the foliate papillae. An islet-like structure with numerous taste buds, was observable on the deep part of the salivary duct of foliate papillae. Large conical papillae were distributed at the posterior part and root of the tongue. After removal of epithelium, filiform papillae of CTCs were appeared to be a thumb or cone-like main core and associating several finger-like short accessory cores. These cores were surrounded an oval concavity. The main core was situated behind the concavity and associated with accessory cores. CTCs of fungiform papillae were cylinder-like with numerous vertically running ridges and with a few concavities seen at the top of the cores. CTCs of vallate papillae and their surrounded circumferential ridge were covered with numerous pimple-like protrusions. The lingual papillae of Common raccoon's tongue had morphological feature of carnivore species.

Estudo morfológico dos músculos do antebraço de mão-pelada, Procyon cancrivorus Cuvier, 1798 / Morphological study of the muscles of the forearm of crab eating raccoon Procyon cancrivorus Cuvier, 1798

O Procyon cancrivorus (mão-pelada) é um carnívoro amplamente encontrado no território brasileiro, porém com escassas informações literárias ao seu respeito. Portanto, justifica-se a escolha deste animal para estudo, tendo como base aspectos morfológicos, que é fundamental para o conhecimento biológico das espécies. Foram utilizados cinco animais mortos por acidente, procedentes de coleta em rodovias. Os músculos pronador redondo, flexor radial do carpo, flexor superficial dos dedos, flexor ulnar do carpo, braquiorradial, palmar longo, flexor profundo dos dedos, pronador quadrado, extensor radial do carpo, extensor comum dos dedos, extensor lateral dos dedos, extensor ulnar do carpo e abdutor longo, foram dissecados e observados macroscopicamente as inserções proximais e distais. Os músculos flexores são inervados pelo nervo mediano, e irrigados por ramos das artérias mediana e ulnar, enquanto os extensores são irrigados pela artéria radial e seus ramos, sendo inervado pelo nervo radial. Para efeito comparativo, o modelo deste carnívoro silvestre foi comparado com a morfologia de carnívoros domésticos (cão e gato), amplamente descritos na literatura. Observou-se então a grande similaridade entre eles.

The Procyon cancrivorus is a carnivorous widely found in Brazil, but with few literary information to them. So why is the choice of species for study, based on morphology, which is fundamental to the understanding of biological species. We used five animals killed by accident, from collection on highways. The muscles round pronator, the radial carpal flexor, superficial flexor of fingers, ulnar flexor of the carpus, brachioradial, long palmar, deep flexor of fingers, square pronator, radial extensor of the carpus, common finger extensor, lateral extensor of toes, ulnar extensor of the carpus and long abductor were dissected and observed macroscopically the proximal and distal insertions. The flexor muscles are innervated by the median nerve and irrigated by branches artery of the median and ulnar the same name, while the extensor muscles are irrigated by the radial artery and its branches, is innervated by the radial nerve. For comparison purposes, the model of wild carnivore was compared with the morphology of domestic carnivores (dogs and cats), widely described in literature. There was then a great similarity between them.

Microvasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor) eye: a scanning electron microscopic study of corrosion casts.

We have studied the vasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor), a nocturnal mammal, using light and scanning electron microscopic examination of corrosion casts. We carried out an identical study in the crab-eating macaque (Macaca fascicularis), which forages only during the daytime, in order to compare the ocular vasculature with that of nocturnal mammals. Our observations in raccoons demonstrated a photoreceptor layer associated with rich lymph and a poorly vascularized retina. The meridian region of the eye, which lies in the horizontal plane and pass around the optic disc, had a markedly sparse capillary network. This horizontal sparse vascular band may correspond to a visual streak. Ciliary process capillaries were delicate, and formed a well-developed and compact network. Choriocapillaries were quite thin and formed a coarse capillary network. This contrasted with the dense retinal and well-extended choroidal capillary networks noted in the macaques. Our findings suggest that the sparse retinal capillary network in raccoons is extremely beneficial for photon capture, thereby allowing the raccoon to see well at night, as the retinal vessels restrict the inflow of photons toward the photoreceptors. The well-developed lymph probably compensates for the sparse retinal capillaries and choriocapillaries and nourishes the retina in the nocturnal raccoon.

Morphology and glycoconjugate histochemistry of the eccrine glands in the snout skin of the North American raccoon (Procyon lotor).

The eccrine nasolabial glands were found in the hypodermis of the nasal plane in the North American raccoon (Procyon lotor). In addition to light and electron microscopic observations, the distribution and selectivity of complex glycoconjugates in the eccrine tubular glands of the raccoon snout skin were studied using various histochemical methods, particularly lectin staining. The secretory epithelium and the luminal secretions exhibited high amounts of glycoconjugates with various saccharide residues (alpha-D: -mannose, alpha-L: -fucose, beta-D: -galactose, beta-N-acetyl-D: -glucosamine, sialic acid). The excretory duct cells also showed positive reactions with most of the histochemical methods applied. The results are discussed with regard to possible functions of the glandular secretions. The complex glycoconjugates that are produced by the eccrine nasolabial glands may be related to moistening of the skin surface as well as protecting the epidermis against physical damage or microbial contamination. This is the first report on the glands in the snout skin of carnivores.

Ultracytochemical demonstration of glycoproteins in the eccrine glands of the digital pads of the North American raccoon (Procyon lotor).

In the eccrine glands of the digital pads of the North American raccoon (Procyon lotor), ultrastructural localization of glycoproteins with various saccharide residues was studied using preferably lectin cytochemical methods. Secretory granules observed in the dark cells exhibited glycoproteins with different terminal sugars (alpha-D-mannose, beta-D-galactose, beta-N-acetyl-D-glucosamine and sialic acid). The cytoplasm of the clear cells contained numerous glycogen particles. Several sugars were also detectable in the surface coat of the plasma membrane of the secretory cells. The results obtained could be helpful in understanding secretion production and cell related secretion functions of the eccrine glands of the raccoon digital foot pads.

Localization of epidermal hyaluronan in the foot pads of the North American raccoon (Procyon lotor).

The localization of the epidermal hyaluronan in the digital foot pads of the North American raccoon (Procyon lotor) was examined by light and electron microscopic histochemical methods. The thick epidermis contained five epidermal layers composed of typical keratinocytes. In the stratum basale and stratum spinosum, hyaluronic acid was clearly detectable at cytoplasmic processes, in close vicinity to the surface coat of the plasma membrane, and/or in the intercellular space between the basal and spinous cells. The results suggest that epidermal hyaluronan that fills the intercellular space may particularly control water maintenance in the epidermis of the raccoon digital pads to guarantee the optimal mechanoreceptive function of the very specific and sensitive sensoric subepidermal equipment in this mammalian species.

Histochemical analysis of glycoconjugates in the eccrine glands of the raccoon digital pads.

The distribution and selectivity of complex carbohydrates in the eccrine glands of the digital pads in the North American raccoon (Procyon lotor) were studied using light and electron microscopic histochemical methods, particularly lectin histochemistry. In the eccrine glands, the dark cells exhibited neutral and acidic glycoconjugates with different saccharide residues (alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine and N-acetyl-neuraminic acid); the clear cells contained numerous glycogen particles and showed a distinct reaction of alpha-L-fucose. The presence of complex carbohydrates with various terminal sugars was evident in the excretory duct cells. In addition, beta-D-galactose and N-acetyl-neuraminic acid residues were mainly observed in the luminal secretion. The glycoconjugates produced by the eccrine glands of the raccoon digital pads may protect the epidermis against physical damage or microbial contamination. In this way, the normal functioning of the sensory apparatus of the foot pads is ensured.

Histochemical analysis of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor).

The distribution and selectivities of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor) were studied by light and electron microscopic histochemical methods, particularly lectin histochemistry. In the modified apocrine glands present, the apocrine secretion mode was combined with exocytosis, whereby the secretory epithelium and the luminal secretion of the ceruminous glands exhibited considerable amounts of complex carbohydrates with various terminal sugars (alpha-D-mannose, beta-D-galactose, alpha-L-fucose, alpha-N-acetyl-galactosamine, beta-N-acetyl-D-glucosamine, N-acetyl-neuraminic acid). Alpha-L-fucose and N-acetyl-neuraminic acid were distinctly prominent in secretory granules or within the free surface coat of the plasma membrane of the glandular cells, as well as in the luminal secretion. Several free sugars (alpha-D-mannose, alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine) were also detectable in the secretion of associated sebaceous glands. The ceruminous gland secretion may control viscoelasticity and/or bacterial degradation of the glandular secretion mixture to improve the protection of the external auditory canal against physical damage or microbial contamination.

Postsynaptic dorsal column and cuneate neurons in raccoon: comparison of response properties and cross-correlation analysis.

The responses of 111 postsynaptic dorsal column (PSDC) neurons in the cervical spinal cord and 51 cuneate neurons with receptive fields on the glabrous skin of the forepaw were studied in anesthetized raccoons using extracellular recording techniques. The PSDC neurons had larger receptive fields than the cuneate neurons, but in both groups the fields never extended onto hairy skin. PSDC and cuneate neurons had approximately the same mean latency to electrical stimulation of the receptive field, but PSDC neurons had significantly lower thresholds. The majority of both PSDC and cuneate neurons also responded to electrical stimulation of an adjacent digit, even though they did not respond to mechanical stimulation of that digit. Cross-correlation analysis of the activity of 51 pairs of PSDC and cuneate neurons recorded simultaneously revealed a significant interaction in 26 pairs during spontaneous activity. In 20 of these neuron pairs, the probability that the cuneate neuron would fire was greater after the PSDC neuron had fired (suggesting a spinocuneate interaction), five pairs showed an interaction in the opposite (cuneospinal) direction, and one pair had a significant inhibitory interaction. These interactions occurred more often when the receptive fields of the two neurons were overlapping than when their fields were on adjacent digits. Frequency response analysis revealed greater coherence for those pairs showing a spinocuneate interaction than for those with a cuneospinal interaction. These results support the hypothesis that the PSDC system exerts a tonic facilitatory effect on cuneate neurons and that there may be some somatotopic organization to the interactions. However, the similar response latencies of the two groups of neurons makes it unlikely that PSDC neurons could contribute to the rapid initial processing of cutaneous information by the cuneate nucleus.

Time course and effective spread of lidocaine and tetrodotoxin delivered via microdialysis: an electrophysiological study in cerebral cortex.

Microdialysis is a useful tool for administering drugs into localized regions of brain tissue, but the diffusion of drugs from the probe has not been systematically examined. Lidocaine (10%) and tetrodotoxin (TTX, 10 microM), drugs typically used in neural inactivation studies, were infused through a microdialysis probe into raccoon somatosensory cortex while evoked responses were recorded at four electrodes equally spaced 0.5--2.0 mm from the probe. The decreases in evoked response amplitude as a function of time and distance from the probe were used as functional measures to describe the time course and spread of the drugs. TTX inactivated distant sites more quickly and to a greater extent than lidocaine. Responses recovered within approximately 40 min after termination of lidocaine, but did not recover for at least 2 h after TTX. Based on these measurements, we estimated that, at the concentrations used, lidocaine has a maximal spread of 2.1 mm, while TTX could spread as far as 4.8 mm from the microdialysis probe. However, in terms of significant inactivation of neuronal activity, lidocaine and TTX have an effective spread of 1 and 2 mm, respectively.

Innervation of the digit on the forepaw of the raccoon.

The innervation of the digits on the raccoon forepaw was examined by using immunochemistry for protein gene product 9.5, calcitonin-gene related peptide, substance P, neuropeptide-Y, tyrosine hydroxylase, and neurofilament protein. The larger-caliber axons in the ventral glabrous skin terminate as Pacinian corpuscles deep in the dermis, small corpuscles and Merkel endings around the base of dermal papillae, and Merkel endings on rete pegs in dermal papillae. Extensive fine-caliber innervation terminates in the epidermis and on the microvasculature. The innervation is more dense in the distal than in the proximal volar pads. Pacinian endings are also concentrated in the transverse crease separating the distal and proximal pads. In the dorsal hairy skin, hair follicles are well innervated with piloneural complexes. Merkel innervation is located under slight epidermal elevations and in some large Merkel rete pegs located at the apex of transverse skin folds just proximal to the claw. No cutaneous Ruffini corpuscles were found anywhere on the digit. The claw is affiliated with dense medial and lateral beds of Pacinian endings, bouquets of highly branched Ruffini-like endings at the transition from the distal phalanx and unmyelinated innervation in the skin around the perimeter. Encapsulated endings are located at the lateral edge of the articular surface of the distal phalanx. Extensive fine-caliber innervation is affiliated with sweat glands and with the vasculature and is especially dense at presumptive arteriovenous sphincters. Virtually all of the sweat gland and vascular innervation is peptidergic, whereas most of the unmyelinated epidermal innervation is nonpeptidergic.

Neuronal vacuolation in raccoons from Oregon.

During a 2-year period (1995-1997), vacuoles were detected in neurons of 21/50 (42% prevalence) raccoons (Procyon lotor) in Oregon. Age or sex predisposition was not apparent. Twenty of these raccoons were from within a radius of 40 km of Corvallis in western Oregon. Microscopically, the vacuoles were variable in size, were in the perikarya, and were consistently present in pontine nuclei. Brain tissues were negative for rabies virus antigen by fluorescent antibody test and for the protease-resistant protein prion by immunohistochemistry. Electron microscopic examination of the brain stem of selected animals revealed accumulation of electron-dense material within neuronal perikarya. Light and electron microscopic examination indicated that the accumulated intracellular material had a high lipid content. These lesions suggest a form of neuronal storage condition. Further research is required to identify the composition of the intracellular lipid material, to elucidate the mechanism of neuronal vacuolation in raccoons, and to understand the basis for the apparent geographic restriction of this lesion.

Distribution of neurons immunoreactive for parvalbumin and calbindin in the somatosensory thalamus of the raccoon.

The aim of this study was to assess the distribution of neurons immunoreactive for parvalbumin (PV), calbindin (CaBP), glutamic acid decarboxylase (GAD), and gamma-aminobutyric acid (GABA) in the somatosensory thalamus of the raccoon and to compare these features to those of other species, especially primates. Immunohistochemistry was used to study the location of these neurons in the ventroposterior nucleus (VP), ventroposterior inferior nucleus (VPI), posterior group of nuclei (Po), and reticular nucleus (Rt). A consistent differential pattern of PV-positive (PV+) and CaBP-positive (CaBP+) cells was found in the somatosensory thalamus. Many PV+ neurons were observed in VP and Rt, but very few were found in VPI or Po. In contrast, CaBP+ neurons were distributed throughout VP, VPI, and Po but were very sparse or absent in Rt. In the VP nucleus, PV+ cells were distributed in clusters separated by interclusteral regions with a sparse distribution of PV+ cell bodies. The distributions of PV+ and CaBP+ cells tended to be complementary to each other in VP; regions with a high density of PV+ neurons had a low density of CaBP+ cell bodies. Double-labeling experiments revealed very few neurons in which PV and CaBP immunoreactivities were colocalized. Cells immunoreactive for GAD or GABA were found in PV-dense clusters of VP; fewer GABAergic neurons were present in the CaBP-dense interclusteral regions of VP and in VPI and Po. GAD+ and GABA+ neurons were most prominently distributed in Rt. We conclude that the distributions of PV+ and CaBP+ cell bodies in the raccoon somatosensory thalamus are very similar to those in primates. The density of GABAergic neurons in the somatosensory thalamus of the raccoon is less than that in the cat and monkey, but the relative distribution of GABAergic neurons in the different somatosensory nuclei is very similar to that in the cat and monkey. These results are discussed in relation to findings in other species and are related to the functions of lemniscal and nonlemniscal somatosensory pathways.