Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ferrets”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMedDate not supplied

Studies on the effects of orally administered Di-(2-ethylhexyl) phthalate in the ferret.

A target-organ study of the effects of the phthalate ester di-(2-ethylhexyl) phthalate (DEHP) has been conducted in mature male albino ferrets. DEHP treatment caused a loss of body weight when administered as a 1% (w/w) diet for 14 months. Additionally marked liver enlargement with associated morphological and biochemical changes was observed. These changes consisted of liver cell enlargement, lysosomal changes, dilatation of the endoplasmic reticulum and the depression of a number of marker enzyme activities. The only other tissue observed to be affected by DEHP treatment was the testes where histological evidence of tissue damage was observed in some animals. Studies on the metabolism of [14C]DEHP in the ferret indicated that the diester was metabolised to derivatives of mono-(2-ethylhexyl) phthalate which were excreted in the urine both unconjugated and as glucuronides. The results obtained have been compared with previous studies in the rat and it is concluded that DEHP is hepatotoxic in both species.

Animals↗
PubMed1992

Ferret red cells: Na/Ca exchange and Na-K-Cl cotransport.

The primary pathway for K influx in ferret red cells is the Na-K-Cl cotransporter and the primary pathway for Ca influx is the Na/Ca exchanger. This makes ferret red cells favorable models for the study of these two transport systems. The evidence that Na/Ca exchange is of primary importance for steady state cell volume regulation and the Na-K-Cl cotransport has a minor role is presented. The approaches to, and results of, the determination of the stoichiometry, of the mechanism, and of the regulation by ATP and Mg, for Na/Ca exchange is contrasted with that taken for Na-K-Cl cotransport.

Animals↗
PubMed1985

Olfactory deprivation enhances normal spine loss in the olfactory bulb of developing ferrets.

Ferrets show a sensitive phase in their postnatal development during which they can become imprinted to food odors. At the same time the number of granule cell spines in the olfactory bulb reaches a maximum, declining significantly thereafter. In ferrets, exposed continuously to saturated levels of geraniol odor in the cage environment, the normal decline in spine number (occurring between day 60 and 90) is significantly enhanced. No such effects were observed during earlier ontogenetic phases. This late postnatal phase is further associated with a marked and significant decrease in total brain weight. The significance of these events to olfactory imprinting and plasticity in the developing brain is discussed.

Acyclic Monoterpenes↗
PubMed1988

A new conditioning paradigm: conditioned limb movements in locomoting decerebrate ferrets.

These experiments address the hypothesis that the trajectory of a forelimb in decerebrate ambulating ferrets can be conditioned to avoid an obstacle encountered during the locomotor cycle. The perturbation was produced by interjecting a bar into the trajectory of the forelimb during swing phase. Over 5-15 steps the flexion of the elbow progressively increased until the forelimb was elevated over the bar. Avoiding the bar often required that the maximum height of the paw during swing phase was doubled. When the bar was no longer thrust into the trajectory of the forelimb, the conditioned behavior persisted for several step cycles. The results indicate that decerebrate ferrets are capable of acquiring a conditioned limb movement that is not a typical conditioned reflex but rather an accentuation of a component of the step cycle performed to avoid an interruption of swing phase.

Animals↗
PubMed1991

Sensory innervation of the mystacial pad fur of the ferret.

The guard and vellus hairs on the muzzles of many mammalian species possess a complex sensory innervation. The observation in the primate that the sources of the endings may be segregated by afferent type to separate terminal nerve branches prompted us to examine the innervation of the mystacial fur on the ferret muzzle. Sections were prepared with reduced silver techniques and serially reconstructed for analysis. The types and orientations of sensory endings in the ferret are similar to those described for the primate. However, we found that any terminal nerve branch could be composed of the full set of afferent types and therefore, there was no consistent segregation. The implications of these results on the afferent to target specificity during development and on multiple cortical representations are discussed.

Animals↗
PubMed1982

Afferent activity evoked by natural stimulation of the biliary system in the ferret.

A technique for the natural stimulation of the biliary system which permits the distinction between noxious and innocuous intensities of stimulation has been developed in the ferret. Male ferrets anaesthetized with urethane have been used. Controlled distensions of the biliary system were produced and the nociceptive nature of the stimulus was ascertained by reflex increases in blood pressure. Levels of biliary pressure that did not evoke changes in blood pressure were considered innocuous. Using this approach electrical activity has been recorded from biliary afferents. Thirty-two recordings were obtained. Twenty-one were of afferents that could be excited by innocuous levels of biliary pressure (low threshold afferents) and 10 recordings were of afferents excited only by noxious stimulation of the biliary system (high threshold afferents). One fibre could not be activated by changes in biliary pressure. Twenty-seven receptive fields were located: 12 in the gallbladder and 15 in the biliary ducts. The relevance of high threshold biliary receptors to visceral nociception is discussed.

Afferent Pathways↗
PubMed1987

Cholinergic innervation of ferret visual system.

The distribution of acetylcholinesterase and choline acetyltransferase in primary visual areas of adult pigmented ferret was determined with cholinesterase histochemistry and choline acetyltransferase immunohistochemistry. In all visual areas the distribution of acetylcholinesterase in the neuropil closely matches that of choline acetyltransferase. In the cerebral cortex acetylcholinesterase and choline acetyltransferase are associated with axons found in every cortical layer and in the white matter. Area 17, identified by Nissl architectonics and cytochrome oxidase histochemistry, is distinguished by having a relatively low density of choline acetyltransferase- and acetylcholinesterase-stained axons in layer IV. Certain cortical non-pyramidal cell types show moderate staining for acetylcholinesterase after relatively long incubations, but no choline acetyltransferase-positive cells are observed in the cortex. In the lateral geniculate nucleus and superior colliculus the levels of choline acetyltransferase and acetylcholinesterase are considerably higher than in cerebral cortex, and choline acetyltransferase-stained axons there display prominent varicosities. The distribution of choline acetyltransferase and acetylcholinesterase in the neuropil of lateral geniculate nucleus and superior colliculus of ferret shows marked laminar variation. For instance, in the lateral geniculate nucleus, the levels of acetylcholinesterase and choline acetyltransferase in the "On" sublaminae of laminae A and A1 are higher than the "Off" sublaminae. In the superficial layers of the superior colliculus the levels of choline acetyltransferase and acetylcholinesterase are highest in the stratum zonale and lowest in the stratum opticum; in the intermediate gray layer of the superior colliculus acetylcholinesterase- and choline acetyltransferase-stained fibres are distributed into dense patches. As in cortex, choline acetyltransferase-positive cell bodies are not found in the lateral geniculate nucleus or superior colliculus, and acetylcholinesterase-stained cell bodies are visible only after long incubations. Cell bodies staining positively for choline acetyltransferase are found in a satellite of the superior colliculus, the parabigeminal nucleus.

Acetylcholinesterase↗
PubMed1990

Evidence for presynaptic 5-hydroxytryptamine3 recognition sites on vagal afferent terminals in the brainstem of the ferret.

Antagonists acting at the 5-hydroxytryptamine3 receptor are potent anti-emetic agents in cases of cytotoxic- and radiation-induced vomiting, and binding sites for these compounds have been described in brainstem areas known to be involved in mediation of nausea and vomiting. We have used autoradiography to examine the distribution of one of these antagonists, [3H]granisetron in the caudal brainstem of the ferret, a commonly used animal model for physiological investigations of emesis. The highest density of binding sites was found to be in the dorsomedial region of the nucleus of the solitary tract, the principal terminus for gastric vagal afferent fibres. Lower levels of binding were observed in the area postrema and the dorsal motor nucleus of the vagus. Following unilateral nodose ganglion excision, displaceable binding of [3H]granisetron in the nucleus of the solitary tract was attenuated on the ipsilateral side by 65%. Bilateral subdiaphragmatic vagotomy abolished binding of [3H]granisetron in the entire dorsal vagal complex. These results provide strong circumstantial evidence that 5-hydroxytryptamine3 receptors are located on vagal afferent terminals in the ferret brainstem.

Afferent Pathways↗
PubMed1994

Distinct laminar differences in the distribution of excitatory amino acid receptors in adult ferret primary visual cortex.

In order to explore the relative contributions of the different ionotropic excitatory amino acid receptor subtypes to signalling in primary visual cortex, we have mapped their distributions in area 17 of adult ferret cerebral cortex by quantitative in vitro autoradiography. D,L-alpha-amino-3-hydroxy-5-methoxy-4-isoxazole propionate (AMPA) and kainate receptors, gating fast, Na(+)-permeable channels, were localized with [3H]dizocilpine maleate ([3H]MK-801). All three radioligands bound to single sites, with KDs of 414 nM [3H]AMPA and [3H]kainate, respectively. Slower-acting N-methyl-D-aspartate receptors, which gate the influx of Ca2+ as well as Na+, were localized with ([3H]AMPA), 78 nM ([3H]kainate) and 16 nM ([3H]MK-801), and each receptor subtype displayed a different laminar distribution pattern within area 17. AMPA receptors were concentrated in superficial layers, with intermediate densities in deep layers and lowest levels in layer IV. Kainate receptor levels were high in layers V and VI and low in all other layers. N-methyl-D-aspartate receptors were more homogeneously distributed than AMPA or kainate receptors, but were expressed at highest levels in layers I and IV and lowest levels in layers V and VI. The binding site densities found in the layers containing most receptors were Bmax = 2812 fmol/mg for [3H]AMPA, Bmax = 626 fmol/mg for [3H]MK-801 maleate and Bmax = 278 fmol/mg for [3H]kainate. Thus, while AMPA receptors were predominant and kainate receptors least abundant in all cortical layers, a complementary relative distribution of excitatory amino acid receptors was apparent, with AMPA receptor density highest in superficial layers, kainate receptor density highest in inferior layers and N-methyl-D-aspartate receptor density highest in the middle granular layer, as well as in layer I. The results indicate that although AMPA receptors are principally involved in excitatory signalling in adult ferret primary visual cortex, kainate receptors in layers V and VI and N-methyl-D-aspartate receptors in layers I and IV may have particularly important roles in mediating synaptic transmission.

Animals↗
PubMed1988

Immunocytochemical localization of hypothalamic luteinizing hormone-releasing hormone in male ferrets.

LHRH-containing neurons within the hypothalamus were immunocytochemically identified in adult male ferrets that were either gonadally intact, castrated, or castrated and treated with testosterone. The distribution of LHRH-immunopositive neuron cell bodies was similar in the three treatment groups. The majority of these cells was located mediobasally in the retrochiasmatic area, including some within the ventrolateral aspects of the arcuate nucleus. These soma were associated with a dense basal LHRH fiber plexus which extended to the median eminence. A smaller number of cell bodies was found slightly more dorsal and lateral to the major concentration at the base and midline. Isolated LHRH perikarya were occasionally observed in dorsal areas of the hypothalamus. There were no differences in the mean total number of hypothalamic LHRH cell bodies identified in the three treatment groups. These results indicate that the documented negative feedback effects of testosterone on LH secretion in male ferrets are not the result of an alteration in the absolute number of neurons capable of synthesizing LHRH.

Animals↗
PubMed1988

Connections of a vagal communicating branch in the ferret. I. Pathways and cell body location.

In contrast to most other species, ferrets possess a single communicating branch connecting the dorsal and ventral vagal trunks immediately rostral to the diaphragm. This branch is being used in physiological studies of gastrointestinal function and emesis. However, the fibre routes which pass through this branch are not known. In this study, the afferent and efferent pathways within this supradiaphragmatic vagal communicating branch of the ferret were studied through the use of the horseradish peroxidase (HRP) tracing technique. The region of the branch was exposed using a thoracotomy and HRP crystals were applied to one of the following: (A) the ventral end of the communicating branch, (B) the dorsal end of the communicating branch, (C) the distal end of the dorsal vagal trunk rostral to the communicating branch or (D) the distal end of the ventral vagal trunk rostral to the communicating branch. Following a 72 hour survival period, the animals were reanaesthetized and perfused. The superior cervical and nodose ganglia and the brain stem were processed using the tetramethylbenzidine method. Following application of HRP to the cut ventral end of the communicating branch, labelled cell bodies were found in the left and right nodose ganglia and in the left dorsal motor nucleus of the vagus. After HRP application to the cut dorsal end of the communicating branch, labelled cells were found in the left and right nodose ganglia. No HRP containing cell bodies were found following HRP application to the cut distal end of either the dorsal or the ventral vagal trunk. These results indicate that several afferent pathways exist within the branch, although only one consistently labelled efferent pathway was found.

Afferent Pathways↗
PubMed1994

The central connections of the vagus nerve in the ferret.

The vagus nerve mediates emesis due to gastric irritation. The central representation of the vagus in the ferret was studied to establish how the nerve is connected to areas important in the regulation of emesis. In a series of 10 ferrets, WGA-HRP injections (10 microliters) were made into the nodose ganglion. After 24-48 h, animals were reanesthetized and perfused transcardially. A block extending from the pons to upper cervical spinal cord was cut at 50 microns and sections reacted. Nodose ganglion injections of WGA-HRP produced labeling of vagal preterminal segments in the ipsilateral dorsal vagal complex including all subnuclei of the solitary complex where the medial and subgelatinous subnuclei received the densest input, the area postrema (AP), which contained a modest amount of terminal label, and the dorsal motor nucleus of the vagus (DMX). Contralateral terminal label, quantitatively much less, was similarly distributed except that within the solitary complex it was limited to the medial and subgelatinous subnuclei. Retrogradely labeled cells formed ipsilateral dorsomedial and ventrolateral columns, corresponding, respectively, to the DMX and the nucleus ambiguus (including retrofacial and retroambiguus).

Animals↗
PubMed1994

Localization of increased collagen in ferret lung tissue after chronic exposure to nitrogen dioxide.

Chronic exposure of experimental animals to moderate levels of nitrogen dioxide (NO2) leads to increased collagen deposition in the lung parenchyma. To localize this increased collagen, lung sections from ferrets exposed to 0.5 or 10 ppm of NO2 4 h daily for 8 or 15 weeks were stained with Sirius red under conditions in which the stain is specific for collagen. Stained areas of respiratory bronchiolar submucosa were compared between NO2-exposed and air-exposed control animals using computer-aided image analysis. The stained areas, relative to the total respiratory epithelium, were increased in the sections from NO2-exposed ferrets as compared to air-exposed controls after 8 or 15 weeks. Removal from exposure after 8 weeks and allowing a 7-week recovery did not result in a decrease in stained areas. In the 10 ppm group, but not in the 0.5 ppm group, the increase was statistically significant. Measurement of total collagen in lung tissue by chemical means showed no differences among the various treatment groups. This study showed that increases in collagen deposition can be readily localized in order to identify the site(s) of potentially adverse effects of air pollutants. It is suggested that the use of Sirius red staining may offer a sensitive method for detection of early fibrotic changes in the lung.

Analysis of Variance↗
PubMed1986

Representation of the cochlea in primary auditory cortex of the ferret (Mustela putorius).

In seven barbiturate-anesthetized ferrets, we explored the acoustically sensitive cortex with conventional microelectrode mapping techniques. A tonotopically organized field was found whose orientation was such that high tonal frequencies were represented dorsally, and low frequencies ventrally. Within this field, neurons typically had short (12-20 ms) latent periods to first spikes. In conjunction with extant anatomical evidence on the connectivity of this region, these data suggest that this field represents the ferret's primary auditory cortex.

Animals↗
PubMed1991

The auditory periphery of the ferret: postnatal development of acoustic properties.

The development of the acoustics of the auditory periphery of the ferret was examined by measuring the spectral transfer functions (STFs) and the directional characteristics of the outer ears of animals ranging in age from postnatal day 32 (P32) to P54. Using an impulse response technique the STFs were obtained from up to 250 locations throughout free space. The directional responses were calculated for frequencies between 1 kHz and 30 kHz. The low frequency roll-off of the STF decreased with increasing age from around 15 kHz at P32 to an adult value of around 8 kHz by P51. The directional responses of the outer ear of the immature ferrets differed significantly from adult animals in a fashion that was consistent with the smaller size of the auditory periphery. However, by P51 the responses were generally within the normal adult range. The implications of the relatively rapid development of the acoustics of the auditory periphery are discussed in terms of the development of mechanisms subserving sound localization.

Acoustic Stimulation↗
PubMedDate not supplied

Intracisternal protein in the type II pneumocyte of the ferret, guinea pig, and mongrel dog.

An intracisternal protein in the type II pneumocyte of the ferret, guinea pig, and mongrel dog was examined by light and electron microscopy and morphometry. The basic pattern of layering in this membrane-bound, ribosome-studded structure (cisternal body) was visualized in cross section as dense layers separated by approximately 0.1 micron with seven fine layers between. In all species the central fine band of the seven was occasionally more prominent than the other six. In the guinea pig the seven fine layers alternated in density from light to dark. The cisternal body of the dog was similar to that of the ferret, but was very much smaller and encountered infrequently. No function has been ascribed to this structure; however, its relation to lamellar bodies, the perinuclear membrane, and surfactant apoprotein is discussed.

Aging↗
PubMed1991

The effect of hydrogen peroxide on smooth muscle tone, mucus secretion and epithelial albumin transport of the ferret trachea in vitro.

The effect of hydrogen peroxide (H2O2) was examined on baseline and on methacholine- and phenylephrine-stimulated smooth muscle tone, mucus volume and lysozyme outputs, and epithelial albumin transport of the ferret whole trachea in vitro. H2O2 (10 microM-10 mM) had no significant effect on tracheal smooth muscle tone but produced concentration-dependent increases in mucus volume, lysozyme and albumin outputs. The potential difference (P.D.) across the trachea was not changed by H2O2. Exposure of the trachea to H2O2 (1 mM) for 2 h reduced the smooth muscle contractions and lysozyme outputs due to methacholine (1 microM) and phenylephrine (10 microM). Methacholine-induced albumin output was significantly increased by H2O2 but that due to phenylephrine was not significantly affected. Exposure to H2O2 had no significant effect on the mucus volume output produced by methacholine or phenylephrine. Thus H2O2 directly stimulates submucosal gland secretion, including secretion from serous cells, and epithelial albumin transport across the ferret trachea but has no effect on tracheal smooth muscle tone. H2O2 reduces methacholine- and phenylephrine-induced smooth muscle contractions and serous cell secretion. H2O2 causes hyperresponsiveness of albumin output to methacholine but not to phenylephrine.

Animals↗
PubMed2004

Glycosylations in demilunar and central acinar cells of the submandibular salivary gland of ferret investigated by lectin histochemistry.

'Resting' submandibular salivary glands obtained post-mortem from mature ferrets of both sexes were examined here. The binding patterns of labelled lectins applied to paraffin sections of tissue slivers fixed in an aldehyde-HgCl2 mixture and the effects of pretreatment procedures on the results were assessed lightmicroscopically. Lectins with affinity for terminal GalNAc residues (DBA, SBA) bound preferentially to demilunar acinar cells which were also strongly reactive with Fuc-directed UEA I. In contrast, lectins with affinity for neuraminic acid (SNA, WGA) bound to central acinar cells where consistent binding of DBA and SNA occurred only after neuraminidase digestion, and variation in the binding of UEA I was seen. The reactivities corresponded with the distribution of secretory granules, but staining in Golgi-like areas occurred in central acinar cells with PNA lectin. The results suggest that glycosylations are more advanced in central than demilunar acinar cells of the ferret submandibular gland. Possibly demilunar and central acinar cells reflect phenotypic changes of a single secretory cell, the 'central' acinar phenotype being influenced by incorporation of neuraminic acid in glycoprotein side chains and by increased Golgi activity.

Animals↗