Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Gills”

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 19 recordsLinked to original sources
PubMed1993

Effects on enflurane on gill withdrawal behaviors and the ability of gill motor neurones to elicit gill contractions in aplysia.

We used the Aplysia gill withdrawal reflex model system in order to study how enflurane effected both gill withdrawal adaptive behaviors and the activity of single identified neurones which are involved with the mediation of the gill withdrawal response. We found that a continuous superfusion of enflurane (0.5 and 1.0%) solution over the abdominal ganglion (the CNS) resulted in an increase in the spontaneous gill respiratory movements; an increase in the spontaneous discharges in identified central motor neurones; and a depolarizing shift in the resting membrane potential of these neurones. Enflurane also significantly effected the ability of the gill motor neurones to elicit a gill contraction when the motor neurone was depolarized to produce action potentials by passing depolarizing current into the neurone. Although in most cases the ability of the motor neurone to elicit a gill withdrawal contraction was decreased, that in one third of the cases was increased. Enflurane may exert its actions by effecting the activity of CNS control neurones which exert both facilitatory and suppressive control over the peripheral nervous system in the gill as well as by having direct effects on the motor neurones.

Journal Article↗
PubMed1987

Mechanoreceptor activity in the gills of the carp. I. Gill filament and gill raker mechanoreceptors.

Physiological properties of gill filament and gill raker mechanoreceptors in the gills of spontaneously breathing carp, Cyprinus carpio L., were analysed. Stroking stimuli applied to gill filaments elicited a phasic mechanoreceptive response, which was recorded from neurons in the epibranchial ganglia. Sustained deflection resulted in a short on-off response. The same neurons were also activated by slight movements of lamellae on a gill filament. The receptive field extended over all the lamellae of one filament at most, but generally covered a small part of it, including both dorsal and ventral lamellae. Deflection of gill rakers also elicited a brief response in epibranchial ganglion neurons. The threshold of both filament-related and gill raker mechanoreceptors was relatively high. They did not respond during normal respiration. It was therefore argued that these receptors do not function in normal respiratory control, but rather serve against mechanical damage from excessive pressure or particles in the water.

Animals↗
PubMed2005

Morphology of the pharyngeal cavity, especially the surface ultrastructure of gill arches and gill rakers in relation to the feeding ecology of the catfish Rita rita (Siluriformes, Bagridae).

Gill arches and the gill rakers of a sluggish, carnivorous catfish, Rita rita, show significant differences of their surface ultrastructure, which are recognized adaptive modifications in relation to food and feeding ecology of fish. Gill rakers on the first and second pairs of gill arches are borne on the oral side and are long and stout at the epi-ceratobranchial union. Gill rakers on the third and fourth pairs of gill arches, in contrast, are borne on the oral and aboral sides and are relatively delicate and short. Long and stout gill rakers on the first and second pairs of gill arches are considered primarily to prevent entry of undesirably large food items into the pharynx. Two types of taste buds, Type I and Type II, occur on the gill arches and the gill rakers. The raised taste buds, located at the apical ends of the gill rakers on the third, fourth, and the fifth pairs of gill arches could increase gustatory efficiency in the pharynx. Differences in the distribution of taste buds on the pharyngeal sides of different gill arches indicate that the posterior part of the pharynx plays a more crucial role in gustation than does the anterior part. Co-occurrence of teeth and taste buds on the epi- and hypopharyngeal bones denotes that food processing and gustation occur simultaneously in the pharynx. Villiform and caniform teeth on the epi- and hypopharyngeal bones are associated with a complex food-processing cycle. Mucous secretions, oozing through mucous cell openings, provide lubrication facilitating smooth passage of food through the pharynx. The angle of curvature at the epi-ceratobranchial union of the first to fourth pairs of gill arches could assist the ventral drag of ceratobranchials in lowering of the pharyngeal floor, thus resulting in a great expansion of the pharynx, as needed to accommodate the large quantities of food captured.

Animals↗
PubMed1999

Responsiveness of gill Na+/K+-ATPase to cortisol is related to gill corticosteroid receptor concentration in juvenile rainbow trout

A positive relationship between receptor concentration and tissue responsiveness is an often-assumed and rarely tested principle in endocrinology. In salmonids, seasonal changes in levels of plasma cortisol and gill corticosteroid receptors (CRs) during the spring indicate a potential role for this hormone in the parr-smolt transformation. It is not known whether these seasonal changes result in alterations in gill responsiveness to cortisol. The relationship between CR concentration and tissue responsiveness was, therefore, examined in the gills of juvenile rainbow trout (Oncorhynchus mykiss). Gill CR concentration (Bmax) and affinity (Kd) were assessed using a radioligand binding assay with the synthetic glucocorticoid triamcinolone acetonide. Gill responsiveness to cortisol was quantified by measuring in vitro Na+/K+-ATPase activity. Gill CR concentration was manipulated by stress or hormonal treatments. Repeated handling stresses resulted in a significant reduction in CR numbers. The decrease in CR Bmax corresponded to a reduction in gill responsiveness to cortisol. Triiodothyronine, but not growth hormone, treatment was found to increase CR Bmax significantly. The increase in CR numbers was correlated with a marked increase in gill responsiveness to cortisol. A significant positive linear relationship exists between the in vitro gill Na+/K+-ATPase activity response to cortisol and CR Bmax (r2=0.614, P<0.001). We have demonstrated that binding sites for cortisol in the gills of rainbow trout have high affinity, high specificity and saturable binding and that the number of binding sites is correlated with the tissue response to cortisol.

Journal Article↗
PubMed2005

Effects of gill abrasion and experimental infection with Tenacibaculum maritimum on the respiratory physiology of Atlantic salmon Salmo salar affected by amoebic gill disease.

The effects of gill abrasion and experimental infection with Tenacibaculum maritimum were assessed in Atlantic salmon Salmo salar with underlying amoebic gill disease. The respiratory and acid-base parameters arterial oxygen tension (P(a)O2), arterial whole blood oxygen content (C(a)O2), arterial pH (pHa), haematocrit and haemoglobin concentrations were measured at intervals over a 48 h recovery period following surgical cannulation of the dorsal aorta. Mortality rates over the recovery period were variable, with gill abrasion and inoculation with T. maritimum causing the highest initial mortality rate and unabraded, uninoculated controls showing the lowest overall mortality rate. Fish with abraded gills tended to show reduced P(a)O2 and lower C(a)O2 compared with unabraded fish. Infection with T. maritimum had no effect on P(a)O2 or C(a)O2. All fish showed an initial alkalosis at 24 h post-surgery/inoculation which was more pronounced in fish inoculated with T. maritimum. There were no significant effects of gill abrasion or infection upon the ratio of oxygen specifically bound to haemoglobin or mean cellular haemoglobin concentration. Histologically, 48 h following surgery, abraded gills showed multifocal hyperplastic lesions with pronounced branchial congestion and telangiectasis, and those inoculated with T. maritimum exhibited focal areas of branchial necrosis and erosion associated with filamentous bacterial mats. All fish examined showed signs of amoebic gill disease with multifocal hyperplastic and spongious lesions with parasome-containing amoeba associated with the gill epithelium. The results suggest that respiratory compromise occurred as a consequence of gill abrasion rather than infection with T. maritimum.

Amebiasis↗
PubMed1975

Studies on the morphology of the gills and gill arches with reference to the blood supply in Notopterus motopterus and Colisa fasciatus.

The morphology of the gills, with their blood supply have been described in Notopterus notopterus and Colisa fasciatus in some detail. Gills are curved and perforated on the dorsolateral and ventrolateral wall of the pharynx. The gills consist of 2 rows of filaments which are stacked one above the other to form a space. The gill filaments are smaller on both the ends and larger in middle. The gill filaments are of pink colour as they are supplied with blood. Gill rakers are large in size in Notopterus notopterus while they are small in Colisa fasciatus. 3 pairs of basibranchials are present in Notopterus notopterus which are covered by median membranous bony plate while 2 basibranchials are present in Colisa fasciatus. 3 pairs of hypobranchials are present in both fishes. 5 pairs of ceratobranchials are present in which Vth ceratobranchial bears teeth. 4 pairs of epibranchials are present. 3 pairs of pharyngobranchials are present in which the tip of the IVth pharyngobranchial bears minute teeth in Notopterus notopterus while in Colisa fasciatus IInd and IIIrd pharyngobranchial bear minute ones. One afferent branchial vessel is present in Notopterus notopterus and Colisa fasciatus in each gill like in other teleostean fishes. One efferent branchial vessel is present in each gill of Notopterus notopterus while in Colisa fasciatus 2 efferent are represented in each gill.

Animals↗
PubMed1987

Mechanoreceptor activity in the gills of the carp. II. Gill arch proprioceptors.

The presence of gill arch proprioceptors in the gills of a teleost, Cyprinus carpio L., is demonstrated and their firing characteristics are analysed. Spontaneous activity of gill arch proprioceptors was recorded from epibranchial ganglia. In paralysed fish the mean discharge rate for 16 receptors ranged from 11.3 impulses X sec-1 (SD 0.3) to 25.7 impulses X sec-1 (SD 0.4). The discharge rate could be influenced by displacement of the main elements of the respiratory pumping system. The receptors showed a tonic response. Their firing frequency was approximately linearly related to gill arch position and, hence, showed a respiratory modulation during ventilation. Gill arch adduction caused a decrease and abduction an increase in discharge rate. In actively breathing fish the mean firing frequency of 30 neurons ranged from 9.9 impulses X sec-1 (SD 0.7) to 40.1 impulses X sec-1 (SD 6.7). These gill arch proprioceptors are located in the cartilaginous strip between the epibranchial and the ceratobranchial of each gill arch and are innervated by the pretrematic branches of the vagal branchial nerves. The role these proprioceptors play in the regulation of gill movements during both feeding and ventilation is discussed.

Animals↗
PubMed2006

Transcriptome profiling the gills of amoebic gill disease (AGD)-affected Atlantic salmon (Salmo salar L.): a role for tumor suppressor p53 in AGD pathogenesis?

Neoparamoeba spp. are amphizoic amoebae with the capacity to colonize the gills of some marine fish, causing AGD. Here, the gill tissue transcriptome response of Atlantic salmon (Salmo salar L.) to AGD is described. Tanks housing Atlantic salmon were inoculated with Neoparamoeba spp. and fish sampled at time points up to 8 days postinoculation (pi.). Gill tissues were taken from AGD-affected fish, and a DNA microarray was used to compare global gene expression against tissues from AGD-unaffected fish. A total of 206 genes, representing 190 unique transcripts, were reproducibly identified as up- or downregulated in response to Neoparamoeba spp. infection. Informative transcripts having GO biological process identifiers were grouped according to function. Although a number of genes were placed into each category, no distinct patterns were observed. One Atlantic salmon cDNA that was upregulated in infected gill relative to noninfected gill at 114 and 189 h pi. showed significant identity with the Xenopus, mouse, and human anterior gradient-2 (AG-2) homologs. Two Atlantic salmon AG-2 mRNA transcripts, designated asAG-2/1 and asAG-2/2, were cloned, sequenced, and shown to be predominantly expressed in the gill, intestine, and brain of a healthy fish. In AGD-affected fish, differential asAG-2 expression was confirmed in samples used for microarray analyses as well as in AGD-affected gill tissue taken from fish in an independent experiment. The asAG-2 upregulation was restricted to AGD lesions relative to unaffected tissue from the same gill arch, while p53 tumor suppressor protein mRNA was concurrently downregulated in AGD lesions. Differential expression of p53-regulated transcripts, proliferating cell nuclear antigen and growth arrest and DNA damage-inducible gene-45beta (GADD45beta) in AGD lesions, suggests a role for p53 in AGD pathogenesis. Thus AGD may represent a novel model for comparative analysis of p53 and p53-regulated pathways.

Amebiasis↗
PubMed1995

Examination of gills from salmonids with bacterial gill disease using monoclonal antibody probes for Flavobacterium branchiophilum and Cytophaga columnaris.

Bacterial diseases of the gills of commercially reared salmonids in freshwater are common problems. They accounted for 18% of all diagnostic submissions to the Atlantic Veterinary College from commercial fish hatcheries. Definitive diagnosis is difficult because of the growth characteristics of the putative bacteria in culture. Research into the pathogenesis of these diseases has also been similarly limited. Monoclonal antibodies (MAbs) were developed to 2 globally significant gill bacterial pathogens, Flavobacterium branchiophilum, the causative agent of bacterial gill disease, and Cytophaga columnaris, the causative agent of columnaris disease of salmonids. These MAbs were then used as the basis for an indirect fluorescent antibody test to assess archived cases of gill disease in our study region. Of the cases tentatively diagnosed based on histopathology as bacterial gill disease, 76.2% tested positively with the MAbs to F. branchiophilum. Also present within 18.7% of these cases were bacteria which reacted positively to the MAbs for C. columnaris. We conclude that the MAbs produced are valuable diagnostic and research probes for common bacterial disease of the gills of salmon and trout in Atlantic Canada. This study also adds further proof that F. branchiophilum acting alone can be sufficient cause for bacterial gill disease.

Animals↗
PubMed1988

Classical conditioning alters the efficacy of identified gill motor neurones in producing gill withdrawal movements in Aplysia.

In a semi-intact preparation of Aplysia californica Cooper, classical conditioning training leads to changes in the synaptic strength at the sensory-motor neurone synapse. However, these changes are neither necessary nor sufficient to bring about the observed behavioural changes of the gill withdrawal reflex. We therefore tested whether the ability of a gill motor neurone to elicit a gill withdrawal response was altered following classical conditioning training of the reflex. We found that following classical conditioning training, the ability of a gill motor neurone to elicit a gill withdrawal response was significantly potentiated. In addition, in control preparations which did not receive classical conditioning training, the ability of a gill motor neurone to elicit a gill response was decreased. Thus, associative learning of this reflex appears to involve alteration in neuronal activity at loci distal to the sensory-motor neurone synapse.

Animals↗
PubMed1981

Arginine vasotocin, an endogenous neuropeptide of Aplysia, suppresses the gill withdrawal reflex and reduces the evoked synaptic input to central gill motor neurons.

The superfusion (15 min) of arginine vasotocin (AVT; 10(-9)--10(-12) M) over the abdominal ganglion of Aplysia californica suppressed the amplitude of the gill withdrawal reflex evoked by tactile stimulation of the siphon, increased the rate of gill reflex habituation, and decreased the evoked synaptic activity to central gill motor neurons. The suppressive effects of AVT on gill reflex behaviors were not due to toxic effects of the hormone since the effects were completely reversible following washout and 3 h rest. The results obtained with AVT were similar to those previously found using the mammalian neuropeptide arginine vasopressin. AVT may act by increasing the activity of central neurons which exert suppressive control over both gill reflex behaviors and evoked activity to central gill motor neurons.

Animals↗
PubMed1985

The influence of surfactants on gill physiology and cadmium uptake in perfused rainbow trout gills.

Cadmium transfer through and the retention of metal in perfused gills from rainbow trout (Salmo gairdneri) has been studied in the presence of two detergents, LAS (linear alkylaryl sulphonate) and NP-10EO (nonylphenol ethoxylate). Accordingly, the effects of the metal and the surfactants on gill viability (vascular resistance, oxygen diffusion capacity, sodium net flux) was measured. Cd had no effect on gill viability either at 0.008 or at 9.0 mumol/liter during a 60-min perfusion period. The viability of the gills deteriorated markedly during 60 min of exposure to 100 mumol/liter LAS and to NP-10EO, or to a mixture of 100 mumol/liter surfactant + 8.1-8.3 mumol/liter Cd. LAS, 100 mumol/liter, reduced Cd transfer, whereas NP-10EO had no effect. NP-10EO increased Cd retention in gill tissue. LAS more than doubled Cd transfer through the gills when tested in concentrations expected to be found in a polluted recipient (0.9 micrograms/liter Cd + 0.05 mg/liter LAS). NP-10EO had no effect on the transfer when tested under these environmentally relevant conditions.

Animals↗
PubMed1985

Gill arch movements and the function of the dorsal gill arch muscles in the carp.

The activity coordination of the dorsal gill arch muscles in a teleost, the carp, is described and the effect of their contraction in combination with the respiratory pump movements is analysed. Based on their origin and insertion the dorsal branchial arch muscles can be divided into three groups: the external branchial arch levators, connecting the branchial arches to the neurocranium, the internal branchial arch levators, connecting the pharyngobranchials to the neurocranium and the dorsal oblique muscles, interconnecting the branchial arches and pharyngobranchials. Functionally, however, there are only two categories with the following properties. The first, which consists of the external branchial arch levators alone, is active during every respiratory cycle, including the cough. These muscles expand the branchial basket through gill arch abduction and, in combination with hyomandibular pumping movements, lower the floor of the buccal cavity. The results of these combined movements are: The gill arches remain evenly distributed within the expanding branchial cavities during inspiration, so that continuity of the gill curtain is maintained. Water flow resistance is reduced also. The volume of water flowing into the buccal cavity during inspiration is increased. The second category, comprising the internal branchial arch levators and the dorsal oblique muscles, contracts only during the cough and else is completely inactive. Contraction of these muscles reinforces the dorsal suspension of the gill arches by firmly anchoring the pharyngobranchials and epibranchials to the base of the skull. In this way strong, caudally directed forces which develop during the intermediate expansion of the cough can be prevented from dislocating the branchial basket.

Animals↗
PubMed1988

FMRFamide prevents habituation and potentiates the gill withdrawal reflex in the isolated gill preparation of Aplysia.

Perfusion of the endogenous neuropeptide, FMRFamide, through the isolated gill of Aplysia facilitated the amplitude of the gill withdrawal reflex (GWR) evoked by tactile stimulation of the gill. The GWR was facilitated in a dose-dependent manner. The facilitation of the GWR produced by FMRFamide perfusion was reversible. In addition to facilitating GWR amplitude, FMRFamide perfusion could also prevent habituation of the reflex. It is hypothesized that FMRFamide may play a role in the peripheral nervous system (PNS) in the gill in the mediation of behavioral state and modulation of adaptive gill behaviors.

Animals↗
PubMed2005

MHC class II+ cells in the gills of Atlantic salmon (Salmo salar L.) affected by amoebic gill disease.

Amoebic gill disease (AGD) is characterised by the association of Neoparamoeba sp. with hyperplastic gill tissue of affected fishes, however, the identity and role of host cells associated with AGD lesions are not known. Here, we investigated cells with an immunological role that were associated with AGD lesions by locating cellular MHC class II beta chain. A tank housing Atlantic salmon (Salmo salar) was inoculated with Neoparamoeba sp., and MHC class II beta chain expression in the gills was qualitatively assessed by immunohistochemistry. In AGD-naïve control fish, MHC class II+ cells were detected basolateral to the interlamellar epithelium as well as upon the interlamellar and secondary epithelium. In the gills of AGD affected fish MHC class II+ cells were observed in both affected and unaffected tissue. Within AGD lesions, numerous MHC class II+ cells were present and these cells exhibited variable levels of expression suggesting that like mammals, MHC class II expression is highly regulated. The presence of MHC class II+ cells within gill lesions is indicative of immune cell trafficking and these cells could contribute in an antigen presentation capacity to the development of an antibody response in fish chronically affected by AGD.

Amebiasis↗
PubMedDate not supplied

Technical evaluation of oxygen transfer rates of fish gills and artificial gills.

An artificial gill, which takes oxygen from water, would enhance the ability of people to function under water for extended periods. Increasing oxygen transfer rate, however, would be essential to the realization of compact, commercially viable equipment. Fish have evolved a variety of techniques to enable them to breathe under water, and their mechanisms must be clarified before compact, high-performance artificial gills can be developed. A model of the secondary lamellae of fish gills, through which oxygen is taken up from water to the blood, was devised, and its structure and oxygen transfer rate were evaluated by computer simulation analysis for carp and dogfish. Oxygen transfer rates were also found for an outside-water-flow artificial gill using a hollow fiber membrane at various fiber packing ratios. The biologic membrane is rate-determining for oxygen transfer through the secondary lamellae. Blood and water side boundary film resistances are small for fish because the blood and water channels are very narrow and numerous. When the fiber packing ratio of the artificial gill is raised, the oxygen transfer rate increases because of lower water side boundary film resistance. An optimum fiber packing ratio should be selected so that there is no major increase in pressure drop and no channeling occurs.

Animals↗
PubMed2004

Gill histopathology of wild marine fish in Tasmania: potential interactions with gill health of cultured Atlantic salmon, Salmo salar L.

This study surveyed conditions in the gills of wild marine fish in Tasmania to determine potential interactions between wild and cultured fish. Wild marine fish of 12 species were captured from three Atlantic salmon farm sites and three reference sites around Tasmania. The survey concentrated on three species, red cod, Pseudophycis bachus, sand flathead, Platycephalus bassensis, and jack mackerel, Trachurus declivus. Seventy-six per cent of salmon pens contained wild fish species. The number of species found in a pen ranged from one to nine and the number of individuals ranged from one to 23. Trichodinids were prevalent and occurred on seven of the 13 species examined. Trichodina occurred on the gills of all but one specimen of red cod. Monogenean gill flukes were observed on all three major species sampled and were abundant on sand flathead. Other parasites and conditions observed in the survey included metacercariae of digenean trematodes, epitheliocystis and cysts of unknown origin. Infestations of trichodinids on red cod and monogenean gill flukes on sand flathead were significantly more intense at farm sites than at reference sites. Atlantic salmon sampled at the same time from the farms were only affected by amoebic gill disease and isopods.

Analysis of Variance↗
PubMed2006

Fooling a freshwater fish: how dietary salt transforms the rainbow trout gill into a seawater gill phenotype.

Numerous fish species, including rainbow trout (Oncorhynchus mykiss), are able to inhabit both freshwater and seawater and routinely migrate between the two environments. One of the most critical adjustments allowing such successful migrations is a remodelling of the gill in which a suite of morphological and molecular changes ensure optimal function in the face of reversing requirements for salt and water balance. The remodelling leads to specific freshwater and seawater gill phenotypes that are readily identified by the orientation and/or quantities of specific ion transporters and the presence or absence of specific cell types. The proximate cues promoting gill phenotypic plasticity are unknown. Here, by assessing the consequences of a salt-enriched diet (in the absence of any changes in external salinity) in the freshwater rainbow trout, we demonstrate that internal salt loading alone, is able to induce various elements of the seawater gill phenotype. Specifically, we show upregulation of three ion transport genes, cystic fibrosis transmembrane conductance regulator (CFTR), Na(+)/K(+)/2Cl(-) co-transporter (NKCC1) and Na(+)/K(+)-ATPase, which are essential for ionic regulation in seawater, and the appearance of chloride cell-accessory cell complexes, which are normally restricted to fish inhabiting seawater. These data provide compelling evidence that gill remodelling during migration from freshwater to seawater may involve sensing of elevated levels of internal salt.

Animal Feed↗