PubMed Health⌕ Search

Biomedical subjects

M Villar

Publications and source records attributed to M Villar.

At least 19 recordsLinked to original sources
PubMed2006

The neuropeptide tyrosine Y1R is expressed in interneurons and projection neurons in the dorsal horn and area X of the rat spinal cord.

The localization of the neuropeptide tyrosine Y1 receptor was studied with immunohistochemistry in parasagittal and transverse, free-floating sections of the rat lumbar spinal cord. At least seven distinct Y1 receptor-positive populations could tentatively be recognized: Type 1) abundant small, fusiform Y1 receptor-positive neurons in laminae I-II, producing a profuse neuropil; Type 2) Y1 receptor-positive projection neurons in lamina I; Type 3) small Y1 receptor-positive neurons in lamina III, similar to Type 1 neurons, but less densely packed; Type 4) a number of large, multipolar Y1 receptor-positive neurons in the border area between laminae III-IV, with dendrites projecting toward laminae I-II; Type 5) a considerable number of large, multipolar Y1 receptor-positive neurons in laminae V-VI; Type 6) many large Y1 receptor-positive neurons around the central canal (area X); and Type 7) a small number of large Y1 receptor-positive neurons in the medial aspect of the ventral horns (lamina VIII). Many of the neurons present in laminae V-VI and area X produce craniocaudal processes extending for several hundred micrometers. Retrograde tracing using cholera toxin B subunit injected at the 9th thoracic spinal cord level shows that several Type 5 neurons in laminae V-VI, and at least a few Type 2 in lamina I and Type 6 in area X have projections extending to the lower segments of the thoracic spinal cord (and perhaps to supraspinal levels). The present results define distinct subpopulations of neuropeptide tyrosine-sensitive neurons, localized in superficial and deep layers of the dorsal, in the ventral horns and in area X. The lamina II neurons express somatostatin [The neuropeptide Y Y1 receptor is a somatic receptor on dorsal root ganglion neurons and a postsynaptic receptor on somatostatin dorsal horn neurons. Eur J Neurosci 11:2211-2225] and are presumably glutamatergic [Todd AJ, Hughes DI, Polgar E, Nagy GG, Mackie M, Ottersen OP, Maxwell DJ (2003) The expression of vesicular glutamate transporters VGLUT1 and VGLUT2 in neurochemically defined axonal populations in the rat spinal cord with emphasis on the dorsal horn. Eur J Neurosci 17:13-27], that is they are excitatory interneurons under a Y1 receptor-mediated inhibitory influence. The remaining Y1 receptor-positive spinal neurons need to be phenotyped, for example if the large Y1 receptor-positive laminae III-IV neurons (Type 5) are identical to the neurokinin (NK)1R-positive neurons previously shown to receive neuropeptide tyrosine positive dendritic contacts [Polgár E, Shehab SA, Watt C, Todd AJ (1999) GABAergic neurons that contain neuropeptide Y selectively target cells with the NK1 receptor in laminae III and IV of the rat spinal cord. J Neurosci 19:2637-2646]. If so, neuropeptide tyrosine could have an antinociceptive action not only via Y1 receptor-positive interneurons (Type 1) but also projection neurons. The present results show neuropeptide tyrosine-sensitive neuron populations virtually in all parts of the lumbar spinal cord, suggesting a role for neuropeptide tyrosine signaling in many spinal functions, including pain.

Animals↗
PubMed2005

Hepatitis C virus reactivation in anti-hepatitic C virus-positive renal transplant recipients.

From 1992 to 2001 hepatitis C virus (HCV) viremia was studied in 53 renal transplant recipients anti-HCV+ with at least 3 months follow-up posttransplant using a quantitative retrotranscriptase-PCR method. HCV-RNA was detected in 45 (85%): 29 of the 34 recipients treated with azathioprine-based therapy and 15 of 18 treated with mycophenolate mofetil. Immunosuppressive therapy type did not affect HCV replication. Three different patterns of HCV-RNA evolution were detected: 13 (28.8%) patients with high RNA-HCV levels; 21 (46.7%) patients with low levels; and 11 (24.4%) patients with viremia elevation. In 10 (90%) of 11 of the last group, HCV viremia was detected before 15 days posttransplantation, significantly earlier than in the other two groups. Thus, replication during the first 15 days after transplantation leads to a high RNA-HCV viral load. No clinical symptoms were related to HCV.

Hepacivirus↗
PubMed2005

Differential gene expression of insulin receptor isoforms A and B and insulin receptor substrates 1, 2 and 3 in rat tissues: modulation by aging and differentiation in rat adipose tissue.

The insulin receptor (IR) occurs as two alternatively spliced isoforms, IR-A (exon 11-) and IR-B (exon 11+), which exhibit functional differences and are expressed in a tissue-specific manner. The IR substrate (IRS) proteins 1, 2 and 3 also differ in function and tissue distribution. Here we show the differential gene expression of IRs and IRSs in several rat target tissues of insulin action. IR-B is significantly higher than IR-A in epididymal white adipose tissue and adipogenesis induces a shift in the alternatively spliced species of IR from the A to the B isoform. Moreover, since aging in the rat is associated with the development of insulin resistance we looked for alterations of expression of these proteins in adipocytes from old rats. Our results reveal that there is a specific decrease in the expression of the IR-B isoform, as well as both mRNA and protein levels of IR, IRS-1 and IRS-3 being significantly decreased, in epididymal adipose tissue from old compared with adult rats. It is concluded that the down-regulation of early components of the insulin transduction pathway in a primary insulin target tissue could be related to the insulin resistance of aging.

Adipose Tissue↗
PubMed2004

Genetic analysis of phenotypic variation for ectomycorrhiza formation in an interspecific F1 poplar full-sib family.

A plant's capability to develop ectomycorrhizal symbiosis is under the control of both genetic and environmental factors. In order to determine the roles played by these different factors, we have performed a quantitative genetic analysis of the ability of poplar trees to form ectomycorrhizas. Quantitative genetics were applied to an interspecific family of poplar for which the two parental genetic maps had already been described, and for which data analyses concerning fungal aggressors were obtained. Quantitative trait loci (QTL) related to ectomycorrhiza formation were identified and located in the genetic maps of the two parents. One QTL was located at a linkage group of the genetic map of Populus trichocarpa showing a high concentration of several QTL involved in the pathogenic interaction with the fungus Melampsora larici-populina, the causal agent of leaf rust.

Basidiomycota↗
PubMed2003

Effect of dehydroleucodine on histamine and serotonin release from mast cells in the isolated mouse jejunum.

OBJECTIVE AND DESIGN: DhL, a lactone isolated from Artemisia douglasiana, prevents gastrointestinal damage elicited by necrosis-inducing agents and exhibits antiinflammatory action. This work examines the effect of DhL on compound 48/80-induced histamine and serotonin release in the isolated mouse jejunum, to determine whether DhL inhibits mediator release from mast cells at the enteric level. MATERIAL: Thirty jejuna from male Balb-c mice were used for the studies. TREATMENT: Samples were incubated sequentially in 9 test tubes containing RBS or 10 microg/ml compound 48/80 or 1.6 mmol/l + 10 microg/ml compound 48/80 at 37 degrees C for 90 minutes (10 min per tube). METHODS: Histamine and serotonin release studies, quantification of granulated mast cells, and evaluation of mast cell ultrastructure were carried out. Differences between groups were determined using analysis of variance followed by Tukey-Kramer multiple comparisons test. RESULTS: Compound 48/80 increased histamine and serotonin release by the tissue (141.95 +/- 62.58 pg/mg tissue vs basal 5.45 +/- 1.04, P<0.01 and 20.04 +/- 2.81 vs basal 9.24 +/- 1.56 ng/ mg tissue, P<0.01, respectively), decreased the number of granulated submucosal mast cells (0.077 +/- 0.0035 vs basal 0.14 +/- 0.015, P<0.05), and elicited evident granule ultrastructural changes. These effects were reduced by dehydroleucodine (19.51 +/- 7.88, P<0.01; 12.69 +/- 1, P<0.05 and 0.143 +/- 0.014, P<0.05, respectively). CONCLUSION: The lactone inhibits compound 48/80-induced histamine and serotonin release from mast cells in the isolated mouse jejunum.

Animals↗
PubMed2003

Mortality and prognostic factors in Spanish patients with systemic sclerosis.

OBJECTIVE: To determine survival and mortality in a cohort of Spanish patients with scleroderma (systemic sclerosis, SSc) and to analyse whether survival is influenced by demographic, clinical or immunological variables or the extent of skin involvement. METHODS: The study included 79 patients diagnosed with SSc and taking part in a study to determine the extent of sclerosis, visceral involvement and immunological alterations. We studied the number of observed and expected deaths (the expected number being based on age- and sex-specific rates in the background population) and derived standardized mortality ratios with their 95% confidence intervals (CI). Cumulative survival after onset of the first symptom was estimated according to the Kaplan-Meier method. The Cox method was used to identify the prognostic factors. RESULTS: The mortality rate was 0.0249 deaths per person-year. Survival at 15 yr was 0.62 (95% CI 0.410-0.778). The standardized mortality ratio was 429.4% (95% CI 222-750). On crude analysis, lung involvement [forced vital capacity (FVC) <70%, pulmonary hypertension], SSc renal crisis, an active capillaroscopic pattern, pericardial effusion and age over 60 yr at diagnosis were associated with shorter survival. On multivariate analysis, only age at diagnosis over 60 yr, FVC <70% and SSc renal crisis were independent prognostic factors. CONCLUSIONS: The mortality rate associated with SSc showed a four-fold increase compared with the background population. Lung involvement and sclerodermal renal crisis were found to be independently associated with reduced survival.

Adolescent↗
PubMed2002

Activation of MAP kinase by insulin and vanadate in adipocytes from young and old rats.

Vanadate has insulin-like effects in adipocytes without stimulating insulin receptor kinase activity. However, it activates IRS-1 associated PI 3-kinase, suggesting that it mimics insulin effects by stimulating signaling elements downstream of PI 3-kinase. Here we analysed the stimulation of MAPK by insulin and vanadate and observed that both elicit a rapid 3.5-4 fold activation which is abolished by wortmannin and PD98059. Simultaneous addition of insulin and vanadate does not result in an additive effect neither on MAPK nor in MEK. Whereas insulin action is transient, vanadate stimulation lasts up to 20 min. In insulin-resistant adipocytes from old rats, insulin stimulates poorly MAPK, whereas a normal activation is achieved with vanadate. We conclude that: (a) insulin and vanadate use a common signaling pathway from PI 3-kinase to MEK and MAPK; (b) vanadate but not insulin, elicits a sustained activation of both enzymes; (c) this pathway is functional in old rat adipocytes.

Adipocytes↗
PubMed2000

[High eradication rates in Helicobacter pylori infection in patients with duodenal ulcer who failed previous eradication therapy].

BACKGROUND: To analyze the effectiveness of a second-line treatment of Helicobacter pylori infection in patients with duodenal ulcer based on previous antibiotic regimen. PATIENTS AND METHODS: Open, prospective, uncontrolled study, but guided by protocol including 30 consecutive patients with endoscopic diagnosis of active duodenal ulcer and failure of a first-line H. pylori eradication treatment diagnosed by urea breath test or a new endoscopy with histology and positive urease test. Treatment consisted in 10 days with omeprazole (20 mg/12 h), bismuth subcitrate (120 mg/6 h), tetracycline (500 mg/6 h) and metronidazole (500 mg/8 h) (OBTM) if previous regimen was with clarithromycin; or 10 days with omeprazole (20 mg/12 h), clarithromycin (500 mg/12 h) and amoxycillin (1g/12 h) (OCA) if previous regimen did not include clarithromycin; using metronidazole (500 mg/8 h) instead of amoxycillin (OCM) in case of allergy. Eradication was defined as a negative 13C-urea breath test 2 months after the end of therapy. RESULTS: One patient had to stop treatment due to the side effects and in 2 patients urea breath test was not performed (3 patients due to the OBTM group). Per protocol eradication was achieved in 25 out of 27 patients (92.6%) and by intention-to-treat eradication was attained in 25 out of 30 cases (83.3%). When both groups analyzed separately, the OCA combination was successful in 5 from 6 patients (83.3%; 95% CI 35.9-99.6); while the OBTM combination was successful in 20 from 21 valuable patients (95. 2%; 95% CI 76.2-99.9). In this second case we make an intention to treat analysis and eradication was achieved in 20 from 24 (83.3%; 95% CI 62.6-95.3). CONCLUSION: The eradicative treatment for H. pylori based in different antibiotics used in subsequent attempts get high eradication rates in patients with duodenal ulcer.

Adult↗
PubMed2000

Antiviral and antiluteolytic activity of recombinant bovine IFN-omega1 obtained from Pichia pastoris.

The gene coding for bovine interferon-omega1 (BoIFN-omega1) was recently cloned and expressed at high levels in the yeast Pichia pastoris. The recombinant BoIFN-omega1 protein shows antiviral activity in different cell lines and has an antiluteolytic effect in cyclic ewes. In this article, we describe a method for purification of BoIFN-omega1 expressed in the methylotrophic yeast P. pastoris and characterization of its activity in vivo. The recombinant protein secreted to the culture medium had low activity because of self-aggregation. BoIFN-omega1 was solubilized using urea and desalting and finally purified by ion exchange chromatography on Q-Sepharose Fast Flow. The yield of purified product was approximately 300 mg/L of fermentation culture, with a specific antiviral activity of 10(8) IU/mg. Its purity was at least 80%. The biologic characterization of purified BoIFN-omega1 was determined by induction of an antiviral state on ewes challenged with 100 lethal doses (LD) of Aujeszky virus and by the extension of the corpus luteum life span and interestrous interval in cyclic cows. Ewes treated with 2 x 106 IU/kg BoIFN-omega1 were protected from Aujeszky virus infection. In cows receiving an intrauterine infusion of 1 mg BoIFN-omega1, equally distributed between the two uterine horns, twice daily from day 14 to day 22 of the experimental estrous cycle, the lifespan of the corpus luteum (25 vs. 19 days) and the interestrous intervals (26 vs. 21 days) were extended when compared with a control group (p < 0.05). We show that recombinant BoIFN-omega1 purified from P. pastoris has high antiviral activity and is an effective antiluteolytic agent in cattle.

Animals↗
PubMed1999

Nitroprusside stimulates contractility and the synthesis of 14C-acetylated PAF-like substances in estrogen primed-mouse uterine horns.

We investigated the effect of sodium nitroprusside (SNP), a donor of nitric oxide, on the formation of platelet-activating factor (PAF) and uterine contractility in mouse uterine horns from mice treated with estrogen. Because the major pathway of PAF synthesis is the remodeling pathway in uterine tissue, we evaluated the incorporation of 14C-acetate into PAF-like molecules. Our results showed that SNP (100-300 mumol/L) caused a transient increase in the synthesis of PAF, which remained cell-associated. The addition of SNP (100-300 mumol/L) to a mouse uterine horn in an isolated organ bath preparation evoked a transient increase in contractility, which was inhibited by hemoglobin (2 micrograms/mL), a nitric oxide scavenger, but not by methylene blue (10 mumol/L), a guanylate cyclase inhibitor. The pharmacological characteristics of the contractions evoked by SNP resembled those evoked after mast cell activation, in that they were blocked by ritodrine (a beta 2 adrenergic agonist, 0.1 mumol/L); indomethacin (a cyclooxygenase inhibitor, 10 mumol/L); ketotifen (a mast cell stabilizer, 1.0 mumol/L); cromolyn sodium (a mast cell stabilizer, 100 mumol/L); pyrilamine (an H1 antagonist, 10 mumol/L); and ketanserine (5HT2 antagonist, 0.1 mumol/L). These data demonstrate that nitric oxide generated from SNP stimulated the synthesis of PAF and evoked contractility in uterine horns from mice treated with estrogen. This result suggests the possibility that these tissue conditions might be favorable for the generation of peroxynitrites, possible mediators of both effects. It is also shown that the contractility evoked by the addition of SNP was not due to production of PAF, because its antagonist, WEB 2086 (10-30 mumol/L, a concentration that blocked contractions evoked by PAF 1 nmol/L), had no effect on the SNP-evoked contractions.

Animals↗
PubMed1998

Oxytocin inhibits the uptake of serotonin into uterine mast cells.

The uptake of serotonin (5HT) into mouse uterine horns, the localization of sites at which this amine could be stored and the effect of oxytocin on 5HT uptake were studied. To analyze the characteristics of the 5HT uptake process, the tissue was incubated with [3H]serotonin. The uptake of [3H]5HT was Na+ dependent and saturable (Kmapp: 166 +/- 15 nM, Vmax: 404 +/- 25 fmol/mg tissue, 30 min (diestrous); and Km: 165 +/- 39 nM, Vmax: 276 +/- 43 fmol/mg tissue, 30 min (estrous), n = 6), and was inhibited by imipramine, fluoxetine and 6-nitroquipazine (IC50: 2; 0.09 and 0.5 nM, respectively). In the myometrium the main 5HT uptake process was localized in uterine mast cells. This was determined by treating the uterine horns with 6-hydroxydopamine, by using an immunocytochemical approach and by studying the outflow of 3H under the action of stimuli directed to either mast cells (compound 48/80: 10 microgram/ml) or sympathetic nerves (high K+: 100 mM and veratridine: 20 microM) in uterine preparations. Oxytocin inhibited [3H]5HT uptake into uterine mast cells during estrus, but not in ovarectomized mice treated with progesterone. Maximal inhibition was attained at 0.03 nM, with a significant reduction in both Kmapp and Vmax (87 +/- 15 nM and 184 +/- 36 fmol/mg tissue/30 min, n = 3, respectively). This effect was reversed by the addition of OVT16, an oxytocin antagonist, at a concentration of 4 nM (Kmapp 158 +/- 35 nM, Vmax: 278 +/- 24 fmol/mg tissue, 30 min, n = 3). These findings support a new potential role of oxytocin and mast cells as a local regulators of serotonin bioavailability in myometrium. Because serotonin is recognized as an important endogenous uterotonic compound, this effect could be considered as an indirect action of oxytocin that may contribute to its potency as a labor inducer after genomic effects of estrogens are expressed in uterine tissue.

Animals↗
PubMed1996

Molecular genetics of rust resistance in poplars (Melampsora larici-populina Kleb/Populus sp.) by bulked segregant analysis in a 2 x 2 factorial mating design.

With random amplified polymorphic DNA (RAPD) markers, we have tagged a genomic region in Populus sp. involved in qualitative resistance to Melampsora larici-populina. Our approach was based on three steps: use of RAPD markers that can be quickly and efficiently researched: application of "bulked segregant analysis" technique on individuals of one interspecific family P. trichocarpa x P. deltoides to search for RAPD markers linked to resistance; and validation of these markers in two other families linked with the first one in a 2 x 2 factorial mating design. Of five detected markers, only one marker M03/04_480 was polymorphic in the three segregating families, involving 89 individuals and four different parents. We have estimated the recombination value of 1 cM with 1 cM sampling error.

Basidiomycota↗
PubMed1995

Histamine, a neuromodulator of noradrenergic transmission in uterine horns from mice in diestrus.

The effect of histamine on [3H]norepinephrine ([3H]NE) release in uterine horns from mice in estrous and diestrous states was studied under two different experimental conditions: resting NE release and stimulus-evoked NE release. It was found that [3H]NE release was higher for the diestrous state under both resting and stimulus-evoked (100 mM K+ and electrical stimulus) conditions. Histamine only potentiated the stimulus-evoked [3H]NE outflow in uterine horns from mice in the diestrous state and from ovariectomized mice treated with progesterone. This effect was dose dependent and was antagonized by H1 but not by H2 or H3 antagonists. R-alpha-Methylhistamine, a H3 agonist, has no effect on stimulus-evoked [3H]NE release. According to these results, it could be concluded that: (a) histamine regulates the NE release from noradrenergic nerve terminals in uterine tissues; (b) this heterologous regulation depends on progesterone predominance and on terminal depolarization; and (c) presynaptic H1 receptors located on noradrenergic terminals could be responsible for such an effect.

Animals↗
PubMed1995

Neuropeptide Y and galanin binding sites in rat and monkey lumbar dorsal root ganglia and spinal cord and effect of peripheral axotomy.

Using monoiodinated peptide YY (PYY) and galanin as radioligands, and neuropeptide Y (NPY) fragments, the distribution of NPY binding sites and its subtypes Y1 and Y2, and of galanin binding sites, was investigated in rat and monkey lumbar (L) 4 and L5 dorsal root ganglia (DRG) and spinal cord before and after a unilateral sciatic nerve cut, ligation or crush. Receptor autoradiography revealed that [125I]PYY bound to some DRG neurons and a few nerve fibres in normal rat DRG, and most of these neurons were small. NPY binding sites were observed in laminae I-IV and X of the rat dorsal horn and in the lateral spinal nucleus, with the highest density in laminae I-II. [125I]PYY binding was most strongly attenuated by NPY13-36, a Y2 agonist, and partially inhibited by [Leu31,Pro34]NPY, a Y1 agonist, in both rat DRG and the dorsal horn of the spinal cord. These findings suggest that Y2 receptors are the main NPY receptors in rat DRG and dorsal horn, but also that Y1 receptors exist. After sciatic nerve cut, PYY binding markedly increased in nerve fibres and neurons in DRG, especially in large neuron profiles, and in laminae III-IV of the dorsal horn, as well as in nerve fibres in dorsal roots and the sciatic nerve. Incubation with NPY13-36 completely abolished PYY binding, which was also reduced by [Leu31,Pro34] NPY. However, the increase in PYY binding seen in laminae I-IV of the ipsilateral dorsal horn after axotomy was not observed after coincubation with [Leu31,Pro34] NPY. NPY binding sites were seen in a few neurons in monkey DRG and in laminae I-II, X and IX of the monkey spinal cord. The intensity of PYY binding in laminae I-II of the dorsal horn was decreased after axotomy. Galanin receptor binding sites were not observed in rat DRG, but were observed in the superficial dorsal horn of the spinal cord, mainly in laminae I-II. Axotomy had no effect on galanin binding in rat DRG and dorsal horn. However, galanin receptor binding was observed in many neurons in monkey L4 and L5 DRG and in laminae I-IV and X of monkey L4 and L5 spinal cord, with the highest intensity in laminae I-II. No marked effect of axotomy was observed on the distribution and intensity of galanin binding in monkey DRG or spinal cord.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1995

Neuronal regulation of c-fos, c-jun, and junB immediate-early genes in rat adrenal medulla.

We have applied in situ hybridization histochemistry, Northern analysis, and immunocytochemistry to study the regulation of the immediate-early gene (IEG) c-fos, c-jun, and junB mRNAs and the respective proteins in the rat adrenal medulla. Electrophoresis mobility shift assay was used to examine changes in AP-1 DNA binding activity. In nontreated rats the mRNA and protein levels for these three IEGs were low. Reflex stimulation of adrenal medulla elicited by a single capsaicin injection induced a rapid and marked elevation in the mRNA levels for these IEGs. Stimulation with nicotine also caused a drastic increase in the mRNA levels, whereas muscarine only induced moderate elevations. c-fos and c-jun were induced strongly in adrenaline cells and only weakly in noradrenaline cells. junB was upregulated mainly in adrenaline cells. The AP-1 DNA binding activity was low in control adrenals, whereas a marked increase was observed after nicotine treatment. Treatment of the animals with a nicotinic (chlorisondamine) or a muscarinic (atropine) receptor antagonist did not change the expression of IEGs studied. The combination of the two drugs, however elevated the mRNA levels for all three IEGs, especially for junB. Pretreatment of the rats with chlorisondamine alone or in combination with atropine diminished the capsaicin-induced increase in c-fos, whereas atropine alone was less efficient. Increase in c-jun mRNA was not affected by these drugs. The capsaicin-induced elevation of junB mRNA levels was not influenced by chlorisondamine or atropine alone, whereas both combined potentiated the effect of capsaicin. The present results demonstrate that neurotransmitters released from splanchnic nerve terminals induce expression of c-fos, c-jun, and junB in adrenal chromaffin cells which results in increased AP-1 DNA binding activity. Although stimulation of both nicotinic and muscarinic cholinergic receptors may mediate the induction of these IEGs, it is possible that also another neurotransmitter(s), in addition to ACh, released from splanchnic nerve terminals is involved in the regulation of their expression, especially of c-jun and junB.

Adrenal Medulla↗
PubMed1994

Plasticity of NO synthase expression in the nervous and endocrine systems.

Using immunohistochemistry and in situ hybridization the effect of nerve injury and of hormones was analysed in sensory and hypothalamic systems and in the pituitary gland. After peripheral axotomy a marked increase in NOS protein and mRNA levels was observed in dorsal root ganglia, the trigeminal ganglion and a less dramatic effect in the nodose ganglia. This effect lasted in the dorsal root ganglion neurons for at least 10 weeks. In the hypothalamic magnocellular neurons a transient increase was observed in the paraventricular and supraoptic nuclei. A similar effect was also seen after salt loading. In the anterior pituitary gland NOS was expressed in gonadotrophs and folliculo-stellate cells. Castration markedly increased NOS levels in the anterior lobe, and this could be counteracted by steroid hormone replacement. Thus, the present results show that the constitutive, neuronal NOS can be dramatically regulated in response to various manipulations, suggesting an important involvement of NO in these situations.

Amino Acid Oxidoreductases↗
PubMed1994

ELISA Quantitation and GC-MS identification of abscisic acid in stigma, ovary and pedicel of pollinated poplar flowers (Populus nigra L.).

A method of fractionation, quantitation and identification of abscisic acid (ABA) in poplar flowers is presented in the context of intra- and interspecific pollination studies in Populus nigra x P. nigra and P. nigra x P. deltoides, respectively. Poplar flowers were dissected into stigma, ovary and pedicel. Abscisic acid concentrations were measured at receptivity and 5 days after pollination in each part of the flower. Abscisic acid was fractionated by reverse-phase HPLC followed by an enzyme-linked immunosorbent assay (ELISA) with anti-ABA polyclonal antibody and GC-MS identification of the immunoreactive ABA fractions. Samples were fractionated and ABA was identified by the presence of a cross-reactive metabolite of ABA in the extracts. The interspecific cross (P. nigra x P. deltoides) had a high concentration of ABA in the pedicel, where abscission occurred, whereas in the intraspecific cross, ABA concentration in the pedicel was low. The results are discussed with reference to the control ABA exerts on the abscission of poplar flowers after interspecific incompatible pollinations.

Journal Article↗