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PubMed2006

An impedimetric immunosensor for the label-free detection of bisphenol A.

Label-free detection of bisphenol A based on the impedance measurement was achieved with an impedimetric immunosensor. The immunosensor was fabricated by the covalent bond formation between a polyclonal antibody and a carboxylic acid group functionalized onto a nano-particle comprised conducting polymer. By using a commercial reagent 4,4-bis(4-hydroxyphenyl) valeric acid (BHPVA), which has an analogous structure of BPA, we have prepared the antigen through the conjugation of BHPVA with bovine serum albumin (BSA) and then produced a specific polyclonal antibody. The immobilization of antibody and the interaction between antibody and antigen were studied using quartz crystal microbalance (QCM) and electrochemical impedance spectroscopic (EIS) techniques. The impedance and mass changes due to the specific immuno-interaction at the sensor surface were utilized to detect antigen and bisphenol A (BPA). The immunosensor showed specific recognition of BPA with less interference than 4.5% from other common phenolic compounds. Under an optimized condition, the linear dynamic range of BPA detection was between 1 and 100 ng/ml. The detection limit of bisphenol A was determined to be 0.3+/-0.07 ng/ml. The proposed immunosensor was applied to a human serum sample and the BPA concentration was determined by the standard addition method.

Antibodies, Monoclonal↗

PubMed2006

Biotin uptake by rabbit corneal epithelial cells: role of sodium-dependent multivitamin transporter (SMVT).

PURPOSE: The objective of this research was to investigate the presence of sodium-dependent multivitamin transporter (SMVT) on rabbit corneal epithelial cells. METHODS: Primary cultured rabbit corneal epithelial cells (rPCECs)and freshly excised rabbit corneas were used for characterization of biotin uptake and transport, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to confirm the molecular identity of SMVT. Liquid chromatography/tandem mass spectrometry (LC-MS/MS) analysis was performed to examine the presence of biotin in rabbit tears. RESULTS: Uptake of biotin by rPCECs was found to be time and concentration dependent with Km of 32.52 microM and Vmax of 10.43 pmol min- 1 mg protein- 1. Biotin was significantly inhibited in the presence of pantothenic acid and lipoic acid. Biotin uptake was found to be energy and Na+ dependent but H+ and Cl- independent. The uptake was inhibited by valeric acid in a concentration-dependent manner but not much affected in the presence of biotin methyl ester and biocytin with no free carboxyl group. Modulators of both PKC- and PKA-mediated pathways had no effect on biotin uptake, but calcium-calmodulin inhibitor significantly inhibited its uptake. Sodium-dependent multivitamin transporter was identified by RT-PCR in rPCECs. Transport experiments across the rabbit corneas revealed the functional localization of SMVT on the apical side of the cornea, and thereby corroborating with in vitro results with cultured corneal cells. Finally, LC-MS/MS analysis showed the presence of biotin in rabbit tears. CONCLUSIONS: Results obtained from both in vitro and exvivo studies suggest the possible role of SMVT expressed on corneal epithelial cells for the uptake of biotin, which co-transports pantothenic acid and lipoic acid. Further, the presence of biotin in tears suggests the physiological significance of this transporter in rabbit corneal epithelium.

Animals↗

PubMed1986

The effects of short-chain fatty acids on the neuronal membrane functions of Helix pomatia. II. Cholinoreceptive properties.

We have examined the effects of short-chain fatty acids on acetylcholine (ACh)-induced transmembrane currents using internally dialyzed neurons of Helix. Decenoic acid, which increased the fluidity of excitable membranes, caused dramatic changes in the voltage sensitivity of ACh currents consisting of an ACh-induced increase in membrane permeability for K+ and Na+ ions and a shift of the Erev of these ACh responses to more positive potentials. Valeric acid, which did not change the membrane fluidity, had no effect on this type of ACh response. Changes of the ENa and ECl had no effect on the size of the decenoic acid-induced shift of the Erev. But the influence of decenoic acid on the voltage sensitivity of ACh-induced currents almost disappeared after the change of the EK by the reduction of the internal K concentration. Decenoic acid had no effect on ACh responses in which K+ ions were not involved in the generation of ACh-induced currents. The results suggest that decenoic acid-induced changes in membrane fluidity modulate cholinoreceptive properties of the neuronal membrane by the inhibition of the K+ carrier involved in the generation of ACh responses.

Animals↗

PubMed1995

New insights on the specificity of penicillin acylase.

In contrast with the general thought that penicillin G acylases (PGAs) were only able to hydrolyse amides or esters of higly hydrophobic acids, we have demonstrated that the PGA from Kluyvera citrophila catalysed the hydrolysis of 4-nitrophenyl esters of acetic, propionic, butyric and valeric acids. Values of kcat. and kcat./Km were greatest for the first compound and less than values for benzylpenicillin by factors of 30 and 7, respectively. 4-Nitrophenyl acetate was hydrolysed faster than 2-nitrophenyl acetate but slower than phenyl acetate. The pH dependence of the reaction was similar to that of benzylpenicillin. Several experiments showed that hydrolysis of 4-nitrophenyl acetate was not catalysed by contaminating esterase activity. The implications for the structural basis of substrate binding are discussed. These substrates open, for the first time, a way to investigate the kinetic parameters of PGA at the presteady-state and provides a new perspective about the role of PGA in nature.

Esters↗

PubMed1982

Pharmacokinetic and pharmacological features of oestradiol valerate.

Natural oestrogenic hormones are the appropriate substances for the therapy of climacteric complaints. After oral or parenteral administration, oestradiol valerate, the synthesis compound contained in various commercially available preparations, is completely converted into the natural substances 17 beta-oestradiol and valeric acid. The 17 beta-oestradiol produced on cleavage of the ester behaves in the organism like the endogenous steroid hormone. Oestradiol valerate and 17 beta-oestradiol are virtually dose-equivalent. No differences in the spectrum of action of the oestrogen and its ester have been found either in animal experiments or man. The pharmacokinetic behaviour and the biotransformation of the 17 beta-oestradiol originating from oestradiol valerate are no different from those of natural 17 beta-oestradiol. Differences of practical significance exist in respect of the quantitative effect of oestradiol valerate following oral and intramuscular administration, whereas 4 mg oestradiol valerate administered intramuscularly is therapeutically sufficient for a period of 2-4 wk (depot effect). As much as 2 mg daily over 3 wk must be administered via the oral route to achieve the same effect. This difference is due to the greatly diverging pharmacokinetic behaviour of oestradiol valerate depending on which of the two modes of administration is employed.

Administration, Oral↗

PubMed1975

Maple syrup urine disease: analysis of branched chain ketoacid decarboxylation in cultured fibroblasts.

Kinetic data are presented for the decarboxylation of branched chain alpha-ketoacids (BCKA) by intact human fibroblasts. Cultured cells of normal individuals and nine patients with different clinical pictures of maple syrup urine disease (MSUD) are studied with both alpha-ketoisocaproic acid (2-oxo-4-methylpentanoic acid (KIC)) and alpha-ketoisovaleric acid (2-oxo-3-methylbutanoic acid (KIVA)) as substrates. One normal cell strain and one patient cell strain is analyzed with alpha-keto-beta-methyl-n-valeric acid (2-oxo-3-methylpentanoic acid (MEVA)) as a substrate. A biphasic degradation kinetic for each BCKA is obtained for normal control subjects. The component with higher substrate affinity is affected in MSUD: for KIC the normally hyperbolic substrate curve is changed to sigmoid shape, for KIVA and MEVA as substrates this component is not detectable at all. Considering qualitative aspects of the BCKA decarboxylation kinetics intact fibroblasts yield the same results as our recent studies with the decarboxylase moieties of partially purified kidney BCKA dehydrogenase of normal individuals and one patient with classic MSUD (27). The decarboxylation velocities for normal and patient fibroblasts with one exception differ widely at low but not at high substrate concentrations of BCKA. To get meaningful data on the residual substrate degradation activities with intact fibroblasts of different phenotypes of MSUD physiologically low substrate concentrations are required in the assay.

Butyrates↗

PubMed1992

[Quantitative direct gas-liquid chromatography for rapid diagnosis of anaerobic infections].

Quantitative direct gas-liquid chromatography (GLC) was performed on 74 specimens of surgical infections and relevant findings were compared with cultural results. In the present study, significant amounts of multiple volatile fatty acids (VFA) and/or succinate were found as markers of anaerobic infections. At least one of the VFA (propionic, isobutyric, butyric, isovaleric or valeric acid) greater than or equal to 0.1 mumol/ml and/or succinate greater than or equal to 0.3 mumol/ml was strong evidence for anaerobic infections. More than 3.5 mumol/ml of butyric acid was interpreted as indication of the presence of Fusobacterium spp. Succinate greater than or equal to 0.3 mumol/ml was associated with the presence of Bacteroides fragilis.

Appendicitis↗

PubMed1991

Autoradiographic characterization of [3H]L-glutamate binding sites in developing mouse cerebellar cortex.

Postnatal changes of [3H]L-glutamate binding sites in mouse cerebellum were studied by in vitro autoradiography. These sites were already present at birth, their density globally increased until postnatal day 25, and at all ages it was higher when Cl- and Ca2+ were present in the incubation buffer. At birth, these binding sites were diffused through the whole cerebellar mass, but became distinctly concentrated in the molecular and the internal granular layers by postnatal day 10. From this age on, binding site sensitivity to ions and glutamate analogues takes a different course in each layer. The external granular layer and the white matter never displayed significant amounts of binding. In the molecular layer the Cl-/Ca2+ effect increased during ontogeny until, in adults, the ion-dependent binding was threefold higher than the ion-independent binding. Quisqualate-sensitive sites accounted for 80% of the total binding sites already at postnatal day 15, while displacement by alpha-amino-3-hydroxy-methyl-4-isoxazolepropionic and ibotenic acids attained the maximum (68%) at postnatal day 60. N-Methyl-D-aspartate displaced glutamate binding (50%) only in the presence of Cl- and Ca2+. Starting from postnatal day 15, binding site density in the molecular layer of lobules VIb and VII of the vermis was lower than in other lobules. In the internal granular layer, the Cl-/Ca2+ effect observed in young animals decreased during development. These transient binding sites were sensitive to quisqualic and ibotenic acid. In adults, the majority of glutamate binding sites were ion-independent and mainly sensitive to D,L-amino-5-phospho-valeric acid and N-methyl-D-aspartate. Throughout development and in both layers, sites displaced by kainate were present at low density and sites displaced by D,L-2-amino-4-phosphonobutyric acid were not detected. The localized postnatal changes of the [3H]L-glutamate binding sites were correlated with the events occurring during growth and maturation of cerebellar structures. The increase of the Cl-/Ca(2+)-dependent binding in the molecular layer is simultaneous with the growth of Purkinje cell dendrites and of parallel fibres and with the formation of the synapses between them. This suggests that these binding sites are localized in these synapses. The changing pattern of sensitivity to different agonists during development might correspond to the maturation of these synapses. The low density of [3H]L-glutamate binding in the molecular layer of lobules VIb and VII probably indicates the presence of specific nerve projections to these areas.(ABSTRACT TRUNCATED AT 400 WORDS)

2-Amino-5-phosphonovalerate↗

PubMed2004

Orientation behaviour of the blood-sucking bug triatoma infestans to short-chain fatty acids: synergistic effect of L-lactic acid and carbon dioxide.

The role of short-chain fatty acids in the host-seeking behaviour of Triatoma infestans larvae was investigated using a locomotion compensator. Several short-chain fatty acids were tested alone over a wide range of doses, or in combination with L-lactic acid (L-LA; 100 microg). Bugs showed no attractive response to single carboxylic acids, but when L-LA was added to airstreams carrying specific intensities of either propionic (C3; 100 microg), butyric (C4; 1 microg) or valeric acid (C5; 1 microg), these mixtures elicited an attractive response, evincing a synergistic effect. No orientation response was observed when caproic acid (C6) was offered with L-LA at the doses tested. Two blends were created: (1) C3, C4 and C5 combined at the effective doses when added with L-LA [C3C4C5 (1)], and (2) C3, C4 and C5 combined at a third of those intensities [C3C4C5 (2)]. Both blends were tested alone, with L-LA (100 microg), with a sub-threshold concentration of CO(2) (300 p.p.m. above the ambient level), and combined with both compounds together. Oriented responses of bugs were only observed with the blend (2) added with L-LA and with the combination of this lure with CO(2). This last combination evoked a behavioural response similar in intensity to that induced by a live mouse.

Animals↗

PubMed1993

Induction of peroxisomal beta-oxidation by a microbial catabolite of cholic acid in rat liver and cultured rat hepatocytes.

The capability of (4R)-4-(2,3,4,6,6a beta,7,8,9,9a alpha,9b beta-decahydro-6a beta-methyl-3-oxo-1H-cyclopental[f]quinolin-7 beta-yl)valeric acid (DCQVA), a catabolite of cholic acid produced by enterobacteria, to induce peroxisome proliferation in vivo and in vitro was studied. Rats given 0.3% DCQVA in the diet for 2 weeks showed marked increases in peroxisomal beta-oxidation, mitochondrial 2,4-dienoyl-CoA reductase and microsomal laurate omega-oxidation activities in the liver compared with control rats given the diet without DCQVA. Cultured rat hepatocytes treated with DCQVA for 72 h also exhibited greatly enhanced beta-oxidation activity. The increased activity was concentration-dependent and the effective concentrations were comparable with those of clofibric acid that produced the same degree of induction in the assay. The results demonstrate that DCQVA is a potent peroxisome proliferator that occurs naturally in rat intestine.

Animals↗

PubMed2002

Odor-stimulated glutamatergic neurotransmission in the zebrafish olfactory bulb.

The role of glutamate as a neurotransmitter in the zebrafish olfactory bulb (OB) was established by examining neuronal activation following 1). glutamate receptor agonist stimulation of isolated olfactory bulbs and 2). odorant stimulation of intact fish. Four groups of neurons (mitral cells, projection neurons; granule cells, juxtaglomerular cells, and tyrosine hydroxylase-containing cells; interneurons) were identified on the basis of cell size, cell location, ionotropic glutamate receptor (iGluR) agonist/odorant sensitivity, and glutamate, gamma-aminobutyric acid (GABA), and tyrosine hydroxylase immunoreactivity. Immunoreactive glutamate levels were highest in olfactory sensory neurons (OSNs) and mitral cells, the putative glutamatergic neurons. The sensitivity of bulbar neurons to iGluR agonists and odorants was established using a cationic channel permeant probe, agmatine (AGB). Agmatine that permeated agonist- or odor-activated iGluRs was fixed in place with glutaraldehyde and detected immunohistochemically. N-methyl-D-aspartic acid (NMDA) and alpha-amino-3-hydroxyl-5-methylisoxazole-4-propionic acid (AMPA)/kainic acid (KA) iGluR agonists and odorants (glutamine, taurocholic acid) stimulated activity-dependent labeling of bulbar neurons, which was blocked with a mixture of the iGluR antagonists, D-2-amino-5-phosphono-valeric acid (APV) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). The AMPA/KA antagonist CNQX completely blocked glutamine-stimulated AGB labeling of granule cells and tyrosine hydroxylase-containing cells, suggesting that, in these cell types, AMPA/KA receptor activation is essential for NMDA receptor activation. However, blocking AMPA/KA receptor activity failed to eliminate AGB labeling of mitral cells or juxtaglomerular cells. Collectively, these findings indicate that glutamate is the primary excitatory neurotransmitter in the zebrafish OB and that iGluR subtypes function heterogeneously in the bulbar neurons.

Animals↗

PubMed1983

Hypolipidemic activity of phthalimide derivatives. 3. A comparison of phthalimide and 1,2-benzisothiazolin-3-one 1,1-dioxide derivatives to phthalimidine and 1,2-benzisothiazoline 1,1-dioxide congeners.

Previously it has been observed that N-substituted phthalimide derivatives with chain lengths of four carbon or oxygen atoms showed potent hypolipidemic activity in rodents at 20 (mg/kg)/day ip. The 1,2-benzisothiazolin-3-one 1,1-dioxide (saccharin) nucleus, itself, had also been observed to be active at the same dose. An investigation was undertaken to examine a series of 1,2-benzisothiazolin-3-one 1,1-dioxide analogues for their hypolipidemic activity in mice and to compare them to their respective phthalimide congeners. In addition, a series of 1,2-benzisothiazoline 1,1-dioxide and phthalimidine analogues was prepared, and their hypolipidemic activity was compared to the phthalimide analogues. These studies show that the respective congeners of 1,2-benzisothiazolin-3-one 1,1-dioxide compared favorably to phthalimide congeners in reducing serum triglyceride and cholesterol levels in male CF1 mice at 20 (mg/kg)/day ip. Of the saccharin derivatives, 3-oxo-1,2-benzisothiazoline-2-propionic acid 1,1-dioxide was the most effective in lowering serum cholesterol levels by 53% after 16 days dosing and 3-oxo-1,2-benzisothiazoline-2-valeric acid 1,1-dioxide lowered serum triglycerides 56% after 14 days dosing. The 1,2-benzisothiazoline 1,1-dioxide and phthalimidine compounds were less active as hypolipidemic agents than their 1,2-benzisothiazolin-3-one 1,1-dioxide and phthalimide analogues, respectively.

Animals↗

PubMed1984

Growth and end-product formation in fermenter cultures of Brochothrix thermosphacta ATCC 11509T and two psychrotrophic Lactobacillus spp. in different gaseous atmospheres.

The effects of different gaseous atmospheres were determined on the maximum specific growth rate (mumax) and end-product formation by Brochothrix thermosphacta ATCC 11509T, Lactobacillus viridescens SMRICC 174 and Lactobacillus sp. SMRICC 173 (homofermentative). The highest mumax-values for Lact. viridescens (0.47/h) and Broc. thermosphacta (0.49/h) were obtained in air. Under anaerobic conditions mumax was reduced, an atmosphere containing CO2 alone giving the greatest reduction. Lactobacillus sp. 173 did not grow in air or N2. Aerobic growth was obtained by adding peroxidase while anaerobic growth occurred in the presence of 5-20% CO2. Carbon dioxide alone reduced the growth rate. All test organisms produced mainly lactic acid anaerobically. Lactobacillus viridescens also produced ethanol while Broc. thermosphacta produced small amounts of ethanol and formic acid. With O2 present, the number of end-products increased for all organisms. Lactobacillus sp. 173 produced small amounts of acetic acid and acetoin together with lactic acid. Oxygen induced acetic acid production in Lact. viridescens and Broc. thermosphacta. Aerobically, Broc. thermosphacta also produced a large amount of acetoin and smaller amounts of 2,3-butanediol, iso-valeric acid and iso-butyric acid. The production of lactic acid by Broc. thermosphacta was completely prevented under strictly aerobic conditions. All test organisms consumed O2 during aerobic growth. Hydrogen peroxide was produced by Lact. viridescens and Lactobacillus sp. 173.

Aerobiosis↗

PubMed1997

In situ derivatisation and extraction of volatile fatty acids entrapped on anion-exchange resin from aqueous solutions and urine as a test matrix using pentafluorobenzyl bromide in supercritical carbon dioxide.

The simultaneous extraction and derivatisation of anion-exchange resin-trapped volatile fatty acids (C2-C5) as their pentafluorobenzyl esters has successfully been performed under CO2 supercritical fluid extraction conditions. Volatile fatty acid standards of acetic, propionic and n-butyric acids (at 20 and 100 ppm) as their ester derivatives were recovered at 78.0-101.5% (C.V. 3.5-7.5%, n=6 and 7). Likewise, acrylic acid recoveries were 57.0-61.0% (C.V. 5.5-5.6%, n=6 and 7). This methodology was applied to the quantitation of acetic, propionic, n-butyric and n-valeric acids in spiked urine as a test matrix. Initial clean-up of phosphate and sulfate in the urine was required prior to anion-exchange application and this was achieved by barium salt precipitation. Recoveries ranged from 36 to 66.5% (C.V. 5.9-14.4%, n=9 and 6).

Anion Exchange Resins↗

PubMed1994

[The effect of cadmium on the protozoan population and rumen fermentation of feed in an artificial rumen].

In our experiment, the effects of 5, 10 and 20 mg cadmium per kg dry matter (DM) on protozoan population and rumen fermentation of feed ration consisting of 11.7 g DM of hay and 2.8 g DM of barley (80: 20%) were followed in artificial rumen (Rusitec). The results of the experiment showed that the addition of 5 and 10 mg cadmium per kg DM less significantly (P < 0.05) decreased the digestibility of DM, organic matter and neutral detergent fibre and significantly (P < 0.01) decreased the digestibility of cellulose of feed ration. It is interesting that the addition of 20 mg cadmium per kg DM did not influence these parameters. Although the total gas production showed a tendency of decrease due to the influence of the addition of 5, 10 and 20 mg cadmium/kg DM, methane and CO2 production was not altered. However, cadmium significantly influenced the production of individual volatile fatty acids-VFA's (mmol/day). The addition of 5, 10 and 20 mg cadmium per kg DM significantly increased acetic acid production (by 10-20%) and decreased propionic acid production (by 18-30%). Therefore, the acetate: propionate ratio was significantly increased (from 1.57 to 2.45-2.60) by the addition of cadmium. The production of n-valeric and iso-valeric acids was also significantly decreased in comparison with the control. The decrease of individual VFA's was more significant at the higher amount of cadmium added into the fermentation system. The proportions of individual VFA's in total VFA production expressed in molar % showed a similar character. The changes in the production of individual VFA's due to the influence of the addition of 5, 10 and 20 mg cadmium per kg DM caused a decrease in energetic efficiency of VFA's (P < 0.001) in comparison with the control. The other parameters of rumen fermentation - utilization of glucose, adenosine triphosphate (ATP) production, fermented hexose, fermented amino acids and fermented organic matter (OMF) were not influenced by the cadmium addition. Although the total microbial matter production in effluent and undigested feed (residues) was significantly (P < 0.001) decreased by the addition of 5, 10 and 20 mg cadmium per kg DM, the efficiency of microbial synthesis expressed as YATP and g microbial N/kg OMF was not changed and achieved the values 11.78-12.68 (YATP), 25.56-28.35 (g microbial N/kg OMF), respectively. The total protozoan population was significantly decreased by the cadmium addition mainly as a result of the decrease of infusoria of Entodinium spp.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal Feed↗

PubMed1996

Opposing effects on blood pressure following the activation of metabotropic and ionotropic glutamate receptors in raphe obscurus in the anaesthetized rat.

The microinjection of L-glutamate (1-6 nmol/rat) and N-methyl-D-aspartate (NMDA 1-10 nmol/rat), ionotropic glutamate receptor (iGluR) agonists, into the nucleus raphe obscurus caused a concentration -dependent increase of arterial blood pressure. In contrast, (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (t-ACPD, 14-42 nmol/rat), a metabotropic glutamate receptor (mGluRs) agonist, caused a concentration-dependent decrease in blood pressure. Pretreatment with D,L-2-amino-phosphono valeric acid (2-APV, 5 nmol/rat) a selective NMDA iGluR antagonist, and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,b] cyclohepten-5,10-imine hydrogen maleate (MK801, 0.9 nmol/rat), a noncompetitive NMDA iGluR antagonist, blocked both the glutamate and NMDA pressor responses, while pretreatment with (+)-alpha-methyl-4-carboxyphenylglycine (MCPG, 0.05 nmol/rat), a mGluR1 antagonist, increased the glutamate-induced pressor effects and blocked the fall in blood pressure induced by t-ACPD. 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX, 0.4 nmol/rat) a non-NMDA iGluR antagonist, did not affected the glutamate-induced hypertension. These observations indicate opposing roles for ionotropic and metabotropic receptors in the glutamate-induced blood pressure changes elicited from the nucleus raphe obscurus. Moreover, we suggest that the glutamate-induced hypertension may be due to the activation of NMDA ionotropic receptor subtypes and the metabotropic receptors may influence this activation through a reduction of excitability at level of synapses.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed1975

[Effect of different types of rations on various characteristics of ruminal and intermediary metabolism in sheep. 1. Formation of volatile fatty acids].

Studies on Ruminal Physiology were made with 15 growing female Merino sheep to investigate the influence of different types of rations on the fermentation of volatile fatty acids. The rations were constructed of green feed, straw and concentrates (type 1) or chemically treated straw pellets + concentrates (type 2). One ration (type 3) consisted of concentrates only. With regard to the total concentration of acids ration 3 was significantly superior to the 2 other types of rations. Moreover, ration 3 produced a specific fermentation pattern of the volatile fatty acids. This was characterized by a significant reduction in the molar proportion of acetate compared with ration 1 and 2 and a significant increase in the level of propionic and valeric acid relative to ration 1. Differences in the fermentation pattern between rations 1 and 2 were mainly limited to differences in the absolute and molar proportions of propionate where the straw pellet rations in each case produced the significant higher values. The acetate to propionate ratio was narrowed in the order of ration 1-3 (4.1 :1, 3.1:1, 2.6-2.9 :1). Statistically wellestablished negative correlations were found to exist between the concentrations of volatile fatty acids and the pH values which were established simultaneously.

Animal Feed↗

PubMed1996

GABAergic agents modify imipramine analgesia.

The influence of GABA agonists and antagonists on analgesic activity of imipramine (IMA, 20 mg/kg, ip) was studied using the hotplate method. Administration of GABAA receptor agonist muscimol (1 mg/kg, ip), GABAB receptor agonist baclofen (3 mg/kg, ip) or GABA-T inhibitor aminooxyacetic acid (25 mg/kg, ip) increased the analgesic effect of IMA. On the other hand pretreatment of GABAA receptor antagonist bicucukline (2 mg/kg ip), GABAB receptor antagonist delta-amino-n-valeric acid (50 mg/kg, ip) or GABA synthesis inhibitor thiosemicarbazide (50 mg/kg, ip) attenuated the IMA analgesia. These results suggest that the analgesic action of IMA may be mediated by functional alteration of a central GABAergic mechanism and/or subsequent stimulation of GABA receptors.

4-Aminobutyrate Transaminase↗