bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the muscarinic receptor mediating contraction of the dog prostate
Authors: Fernández J. L. G. , Rivera L. , López P. G. , Recio P. , Vela‐Navarrete R. , García‐Sacristán A. 
Published: March 2003

1 We have studied the effects of muscarinic cholinoceptor agonists and subtype‐preferring antagonists on the isometric contraction of smooth muscle strips from dog prostate. 2 Acetylcholine and carbachol induced contraction of prostate strips from the peripheral zone, (‘the capsule’). Bethanechol contracted the tissue but not at lower doses. McN‐A‐343 and oxotremorine‐M showed the same effects. 3 Blocking α‐ and β‐adrenoceptors with phentolamine and propranolol, respectively, did not modify carbachol‐induced contractions. 4 The nicotinic receptor blocker, hexamethonium (10−−6–10−−4 m) did not affect the contractile response evoked by a single dose of carbachol (10−−5 m), whilst the muscarinic receptor antagonist, atropine (10−−11–10−−9 m), inhibited it in a competitive manner. 5 The muscarinic M1 (pirenzepine), M2[AF‐DX 116, himbacine (M2/M4) and methoctramine], M3 (HHSID and f‐F‐HHSID), and putative M4 (tropicamide) antagonists reduced significantly the carbachol‐induced contractions. The pIC50 values were: atropine (10.01) > himbacine (8.3) > methoctramine (7.85) > AF‐DX 116 (7.60) > HHSID (7.21) > p‐F‐HHSID (7.10) > pirenzepine (7.30) > tropicamide (7.00). 6 The antagonist profile indicates that an predominant M2 receptor subtype could mediate the muscarinic contraction in the canine prostate.
Involvement of cyclic GMP‐dependent mechanism in the nitrergic relaxation of the bovine oesophageal groove
Authors: Barahona M. V. , Sánchez‐Fortún S. , San Andrés Md , Rodríguez C. , Andrés M. San 
Published: March 2003

1 The present study was designed to investigate the mechanisms involved in the relaxations to nitric oxide (NO) of bovine oesophageal groove preparations suspended in organ baths for isometric tension recordings. In preparations treated with guanethidine (10−−5 m) and atropine (10−−7 m) to block adrenergic neurotransmission and muscarinic receptors, respectively, NO released from nitrergic nerves by electrical field stimulation (EFS, 0.5–16 Hz, 1 ms duration, 20 s trains) and exogenously applied as an acidified solution of sodium nitrite (NaNO2, 10−−6–10−−3 m) caused frequency‐and dose‐dependent relaxations of noradrenaline (NA, 10−−5 m)‐precontracted preparations. 2 Incubation with an inhibitor of NO‐stimulated soluble guanylate cyclase, 1H‐[1,2,4]oxadiazolo[4,3,‐a]quinoxalin‐1‐one (ODQ, 3 × 10−−6m, for 30 min) did not change the basal tension of oesophageal groove strips but inhibited relaxations to EFS and to exogenous NO. 3 Treatment with iberiotoxin (10−−7 m) and apamin (5 × 10−−7 m), which are blockers of large and small conductance Ca2+‐activated K+ channels, respectively, did not modify basal tension or the relaxations induced by EFS and exogenous NO. Incubation with iberiotoxin (10−−7 m) or apamin (5 × 10−−7 m) plus ODQ (3 × 10−−6 m) significantly reduced the relaxations to EFS and exogenous NO. However, in both cases the reductions were similar to the inhibition caused by ODQ alone. The combined addition of charybdotoxin (3 × 10−−8 m) and apamin (5 × 10−−7 m) did not change relaxations to EFS or exogenous NO of the bovine oesophageal groove. 4 The blocker of ATP‐sensitive K+ channels, glibenclamide (10−−6 m), had no effect on either resting tension or relaxations induced by both EFS and exogenous NO. Combined treatment with ODQ (3 × 10−−6 m) and glibenclamide (10−−6 m) did not produce additional inhibition compared to ODQ alone. 5 The present results indicate that NO acts as an inhibitory neurotransmitter by relaxing bovine oesophageal groove smooth muscle through a guanylate cyclase‐dependent mechanism which does not appear to involve the opening of K+ channels.
Response to isoprenaline of rabbit detrusor muscle following exposure to 5, 8, 11, 14 eicosatetraynoic acid. Role of prostanoids on beta‐adrenergic‐evoked response
Authors: Bolle Paola , Fidanza Stefano , Tucci Paolo 
Published: March 2003

1 Incubation with indomethacin or ibuprofen causes a fall in basal tone and inhibits isoprenaline‐evoked response in rabbit detrusor muscle strips. To ascertain whether this is due to cyclo‐oxygenase inhibition, we investigated the influence on β‐adrenoceptor response of 5, 8, 11, 14 eicosatetraynoic acid (ETYA) which, unlike nonsteroidal anti‐inflammatory drugs, has no action in vitro other than cyclo‐oxygenase inhibition. 2 Incubation of detrusor strips with ETYA (7 or 14 μm) for 60 min significantly reduced tissue response to isoprenaline by an extent similar to that induced by indomethacin, but only slightly affected basal tone. 3 In tissues preincubated with indomethacin, the addition of PGE2 or PGE1 to restore basal tone, completely re‐established isoprenaline‐evoked responses. 4 Our findings in rabbit detrusor strips show that inhibition of cyclo‐oxygenase and of prostanoid production is the main mechanism involved in lowered β‐adrenoceptor evoked response. 5 In addition, these findings strengthen the conviction that ibuprofen and indomethacin act largely through mechanisms other than inhibition of prostanoid production.
Sensory neuropeptides are not involved in acetaldehyde‐induced bronchoconstriction in guinea‐pigs
Authors: Myou S. , Fujimura M. , Kita T. , Katayama N. , Abo M. , Yoshimi Y. , Nishitsuji M. , Nomura S. , Nakao S. 
Published: March 2003

1 Alcohol‐induced asthma is characterized by worsening of asthmatic symptoms after alcohol ingestion. Acetaldehyde, a metabolite of ethanol, is thought to be a main factor of alcohol‐induced asthma. Although airway sensory nerves are known to be activated in asthma, there have been no studies investigating the role of tachykinins in the airway response to acetaldehyde. The purpose of the present study was to evaluate the involvement of tachykinins on acetaldehyde‐induced bronchoconstriction in guinea‐pigs. 2 After capsaicin desensitization or intravenous administration of 10 mg kg–1 FK224, a NK1 and NK2 dual antagonist, airway responses to ascending doses (2.5–20 mg ml–1) of inhaled acetaldehyde was examined using a modified Konzett–Rössler method in guinea‐pigs. 3 Inhalation of acetaldehyde induced bronchoconstriction in a dose‐dependent manner. The FK224 failed to reduce the acetaldehyde‐induced bronchoconstriction. Pretreatment with capsaicin did not alter the bronchoconstriction induced by acetaldehyde at a dose of 2.5–10 mg ml–1. Pretreatment with capsaicin slightly, but significantly, inhibited bronchoconstriction induced by 20 mg ml–1 of acetaldehyde. 4 The present results suggest that tachykinins are not involved in acetaldehyde‐induced bronchoconstriction in guinea‐pigs.
Forest response to climate changes in Atlantic Equatorial Africa during the last 4000 years BP and inheritance on the modern landscapes
Authors: Vincens Annie , Schwartz Dominique , Elenga Hilaire , Reynaud‐Farrera Isabelle , Alexandre Anne , Bertaux Jacques , Mariotti André , Martin Louis , Meunier Jean‐Dominique , Nguetsop François , Servant Michel , Servant‐Vildary Simone , Wirrmann Denis 
Published: March 2003

SummaryThis review paper synthesizes the recent published palaeoecological results obtained in Atlantic Equatorial Africa (ECOFIT program) on the history of forest ecosystems and inferred climate changes during the past 4000 years. Evidence are mainly provided by pollen analysis carried out at nine sites from Congo, Cameroon and Ghana, locally supported by macroflora remains, phytoliths, diatoms, δ13C and mineralogical data.At all the sites, except Lake Bosumtwi (Ghana), following a large expansion of rain and mesophilous forests until 3000 years BP, a major change is registered, affecting floristic composition, structure and geographical distribution. According to the hydrological sensitivity of the different sites, local openings of the forests with development of heliophilous formations and/or isolated enclosed savannas are observed at the most humid sites; complete disappearance of forested formations at the driest. The agreement between pollen records, hydrological and hydrobiological data definitely demonstrates that an arid event has been the primary driving factor of this change and is responsable for the main features of the modern landscapes in Atlantic Equatorial Africa. Moreover, the most recent palaeoecological data obtained in Congo (Lake Sinnda), indicate that this Late Holocene increasing aridity was of longer duration, from 4000 to 1300 years BP, and more progressive than previously inferred. A new expansion of forests is locally detected c. 900–600 BP despite increased human impact.
Reconstruction of adaptive radiation in insular habitats using integrated biogeographic information
Authors: Knox E. B. 
Published: March 2003

Summary AimTo develop an analytical method for accurately reconstructing the biogeographic events associated with adaptive radiation in a system of insular habitats. LocationAn idealized, two‐dimensional model system of insular habitats is based on the altitudinally stratified vegetation zones on the island‐like mountains of eastern Africa. MethodsThe model system is treated as a two‐dimensional array of insular habitats, and adaptive radiation is treated as a ‘space‐filling’ process according to six premises based on uniformitarian principles. Previous approaches to this class of problems have used (1) Hennig's progression rule, (2) optimization of biogeographic character states, and (3) reasoned argumentation with an intuitive synthesis of information. The strengths and limitations of these previous approaches are evaluated. ResultsA closed analytical method is presented that accurately reconstructs biogeographic events. This methodological approach integrates atomized information back up to the appropriate level of biological organization and has general applicability to phylogenetic analysis. Main conclusionsIn a truly evolutionary approach to phylogenetic systematics and biogeography, the initial analysis of the pattern of descent should be complemented with a subsequent analysis of the pattern of modification. The method presented here offers one approach to analysing the pattern of modification, which in this case constitutes biogeographic movement.
Structure, floristic composition and natural regeneration in the forests of Cat Tien National Park, Vietnam: an analysis of the successional trends
Authors: Blanc L. , Maury‐Lechon G. , Pascal J.‐P. 
Published: March 2003

AbstractThe forests in Cat Tien National Park, appear as a mosaic of different communities, distinct from each other with respect to their floristic and structural parameters. The objectives of this study are (1) to characterize the different formations occurring in the lowland part and (2) to identify the main successional trends in the area. Understanding forest succession is important for silviculture and restoration of forests and land rehabilitation, as adequate information on the ecological role of local species in the functioning of the forests is not available in Vietnam. Five plots (1 ha each) were established in the lowland part of Cat Tien National Park, where all the trees ≥ 10 cm d.b.h. (diameter at breast height) were located, measured and identified. A systematic sampling was made to assess the regeneration. Three plots (A, C and D) can be considered as secondary forests on the basis of their structural parameters. Plots A and C are dominated by Lagerstrmia calyculata and plot D by Dipterocarpus alatus. The other two plots can be regarded as mature forests. Plot B corresponds to a semideciduous formation dominated by Lagerstrmia calyculata and Fabaceae species, and plot E to an evergreen one dominated by dipterocarp species. The floristic composition of plots A and C will change in the future because dominant canopy species are rare or absent in regeneration. A correspondence analysis performed on the number of trees per species shows two kinds of successional trends: one from A to B on shallow and drier soils, and another from C to E on deeper and wetter soils.
The relative importance of trees versus lianas as hosts for phytophagous beetles (Coleoptera) in tropical forests
Authors: Ødegaard Frode 
Published: March 2003

AbstractAimInsect assemblages associated with lianas in tropical forests are poorly studied compared with those associated with trees. The importance of lianas for the maintenance of local species richness of insect herbivores in tropical forests is therefore poorly understood. With this in mind, a comparative study of the relative importance of trees and lianas as hosts for phytophagous beetles was carried out.LocationThe study area was located in the canopy of a dry tropical forest in Parque Natural Metropolitano, Panama province, Republic of Panama.MethodsA crane system was utilized to access the canopy. The number of species and host specialization of adult phytophagous beetles associated with twenty‐six liana species of ten different families, and twenty‐four tree species of twelve different families were compared.ResultsA total of 2561 host associations of 697 species of beetles were determined (1339 for trees and 1222 for lianas). On average 55.8 ± 6.8 beetle species were found to be associated with each tree species while the comparable number for lianas was 47.0 ± 6.1.The pooled numbers of phytophagous beetle species associated with trees and lianas, respectively, were not significantly different. However, there were significantly more species feeding on green plant parts on lianas than on trees, and there were significantly more wood eaters on trees than on lianas.Phytophagous beetles associated with lianas were significantly more specialized than the tree associates due to a higher degree of specialization among the species feeding on green plant parts of lianas. Wood eaters and flower visitors showed no differences in host specialization on different growth forms.Main conclusionThe present study shows that lianas are at least as important as trees for the maintenance of local species diversity of phytophagous beetles at this site. The mechanisms that drive the patterns can only be hypothesized. Plant architecture, size, and length of growing season are probably involved. Further studies, should include measurements of plant traits to elucidate experimentally what mechanisms that drive the patterns. Additional insight would come from similar studies in other forest types, and also studies of other major taxonomic groups of arthropod herbivores.
Long‐term change in the floristic composition and vegetation structure of Carnac Island, Western Australia
Authors: Abbott Ian , Marchant Neville , Cranfield Ray 
Published: March 2003

AbstractAim To document changes in the floristic composition and vegetation structure of Carnac Island during a period of 40 years. This paper presents a synthesis of all available floristic and vegetational information.Location Carnac Island is 8 km offshore from Fremantle, south‐west Western Australia.Methods Comparison of lists of plant species for 1951, 1958/9, 1966/7, 1975/6 and 1995–6. Comparison of vegetation, based on structural and floristic elements, for 1951, 1965, 1972, 1984 and 1995.Results Floristic composition (both native and exotic species) changed most dramatically in the period 1975/6–1995/6, with a 37% reduction in number of plant species. The number of annual and perennial native species present in 1995/6 was most similar to that in 1951. The most remarkable change in the flora has been the increase in annual exotic species since 1951. Immigration and extinction rates were greatest in the periods 1951–58/9 and 1958/9–1966/7, respectively. Vegetation structure has also altered, involving a reduction in height of dominant species from 3–4 m to 1 m as Acacia rostellifera and Olearia axillaris have declined in distribution. The weed species Mesembryanthemum crystallinum (first recorded 1975) and Malva parviflora (1958) now dominate the vegetation of half the island.Main conclusions Five factors are considered to have contributed to botanical change: nesting seabird populations, eradication of the rabbit in 1969, drought, increased saltload from occasional cyclones in summer or autumn, and competition from increasing dominance of several weed species. Several of these factors have operated in opposing ways with respect to plant species richness and vegetation cover. Experimental studies are required to determine the strength of these interactions. Two weed species, Zantedeschia aethiopica (first recorded 1966) and Lycium ferocissimum (1992) have the potential to dominate the vegetation of the island.
Last glacial maximum biomes reconstructed from pollen and plant macrofossil data from northern Eurasia
Authors: Tarasov P. E. , Volkova V. S. , Webb T. , Guiot J. , Andreev A. A. , Bezusko L. G. , Bezusko T. V. , Bykova G. V. , Dorofeyuk N. I. , Kvavadze E. V. , Osipova I. M. , Panova N. K. , Sevastyanov D. V. 
Published: March 2003

AbstractPollen and plant macrofossil data from northern Eurasia were used to reconstruct the vegetation of the last glacial maximum (LGM: 18,000 ± 2000 14C yr bp) using an objective quantitative method for interpreting pollen data in terms of the biomes they represent (
Prentice et al., 1996
). The results confirm previous qualitative vegetation reconstructions at the LGM but provide a more comprehensive analysis of the data.Tundra dominated a large area of northern Eurasia (north of 57°N) to the west, south and east of the Scandinavian ice sheet at the LGM.Steppe‐like vegetation was reconstructed in the latitudinal band from western Ukraine, where temperate deciduous forests grow today, to western Siberia, where taiga and cold deciduous forests grow today. The reconstruction shows that steppe graded into tundra in Siberia, which is not the case today.Taiga grew on the northern coast of the Sea of Azov, about 1500 km south of its present limit in European Russia. In contrast, taiga was reconstructed only slightly south of its southern limit today in south‐western Siberia.Broadleaved trees were confined to small refuges, e.g. on the eastern coast of the Black Sea, where cool mixed forest was reconstructed from the LGM data.Cool conifer forests in western Georgia were reconstructed as growing more than 1000 m lower than they grow today. The few scattered sites with LGM data from the Tien‐Shan Mountains and from northern Mongolia yielded biome reconstructions of steppe and taiga, which are the biomes growing there today.
Interactive effects of land use and other factors on regional bird distributions
Authors: Allen Andrew P. , O’Connor Raymond J. 
Published: March 2003

AbstractAimWe assessed the independent and interactive effects of land use and other factors on regional distributions of lake shore bird assemblages.LocationAnalyses were restricted to lakes of the northeastern United States (New England, New York, New Jersey).MethodsLake shore bird and habitat data were collected from a regional sample of 186 lakes between 1991 and 1995. Local and regional gradients in environmental attributes of the lakes and their watersheds, and in bird species composition, were characterized using detrended correspondence analysis. Bird assemblages were also characterized with respect to species diversity, total bird abundance, and absolute and proportional abundance for neotropical migrants, omnivores and tree foragers. The assemblage measures were compared with the environmental gradients and with the environmental variables from which those gradients were derived using correlations, linear regression and bivariate plots.ResultsAnthropogenic variables (e.g. human density) and nonanthropogenic variables (e.g. climate, forest composition, lake productivity) were highly confounded regionally, reflecting the influence of climate and geomorphology on land use and, in turn, the influence of land use on the environment. Moving south along the regional gradient to watersheds with more intensive land use, changes in bird assemblage structure were consistent with anthropogenic effects on the avifauna attributable to forest fragmentation: total bird abundance increased, fragmentation‐tolerant species were encountered more frequently, the proportional abundance of omnivores increased and the proportional abundances of tree foragers and neotropical migrants decreased. Bird diversity, as assayed using rarefaction, peaked at an intermediate position along the regional gradient, as did the absolute abundances of tree foragers and migrants.Main conclusionsWe propose that some community attributes peaked at an intermediate position along the regional gradient as a result of the interactive effects of land use and other factors on this region’s avifauna, with broad‐scale anthropogenic factors constraining assemblages on the urbanized lakes, and climate or other nonanthropogenic factors constraining assemblages on the pristine lakes. Anthropogenic and nonanthropogenic factors of similar scale and magnitude thus acted in concert to shape regional bird distributions.
Spatial variation and biogeography of sand forest avian assemblages in South Africa
Authors: Van Rensburg Berndt J. , Chown Steven L. , Van Jaarsveld Albert S. , McGeoch Melodie A. 
Published: March 2003

AbstractAim To examine biogeographical affiliations, habitat‐associated heterogeneity and endemism of avian assemblages in sand forest patches and the savanna‐like mixed woodland matrix.Location Two reserves in the Maputaland Centre of Endemism (MC) on the southern Mozambique Coastal Plain of northern KwaZulu‐Natal, South Africa.Methods Replicated surveys were undertaken in each of the two habitat types in each reserve, providing species abundance data over a full year. Vegetation structure at each of the survey sites was also quantified. Differences between the bird assemblages and the extent to which vegetation structure explained these differences were assessed using multi‐variate techniques. Biogeographical comparisons were based on species presence/absence data and clustering techniques.Results Bird assemblages differed significantly between habitats both within a given reserve and between reserves, and also between reserves for a given habitat. Differences in vegetation structure contributed substantially to differences between the avian assemblages. Of the four species endemic to the MC, three (Neergaard’s sunbird, Rudd’s apalis, and Woodward’s batis) were consistently present in sand forest. The fourth (pink‐throated twinspot) preferred mixed woodland. None of these endemic species was classed as rare. In the biogeographical analysis, both the sand forest and the mixed woodland bird assemblages were most similar to bird assemblages found in the forest biome or the Afromontane forest biome, depending on the biome classification used.Main conclusions The close affinities of sand forest and mixed woodland assemblages to those of the forest biome are most likely due to similarities in vegetation structure of these forests. Bird assemblages differ between the sand forest and mixed woodland habitats both within a given reserve and between reserves, and also between reserves for a given habitat. These differences extend to species endemic to the MC. Thus, conservation of sand forest habitat in a variety of areas is necessary to ensure the long‐term persistence of the biota.