The pelagic food web of the Western Adriatic Sea: a focus on the role of small pelagics.

The Adriatic Sea is one of the largest areas of occurrence of shared small pelagic stocks and the most fished area of the Mediterranean Sea, which is in turn one of the most exploited basins of the world. The variations in the stable isotope contents (δ15N and δ13C) were determined for three small pelagic fishes (i.e., Engraulis encrasicolus, Sardina pilchardus, and Sprattus sprattus, respectively known as anchovies, sardines and sprats) collected across the western side of the basin. Our data allowed to determine the width and features of their trophic niches, to assess potential overlap or resource partitioning among them, and likely anticipate species adaptation to future climate change scenarios. Moreover, variations in stable isotope contents were correlated to both resource availability (i.e., mesozooplankton) and environmental variables. The high productivity and in turn the high resource availability of the basin, especially in the northern part, resulted in favor of the resource partitioning that occurs in each sub-area of the Adriatic Sea among the three species. Medium-sized specimens of the three species mostly fed on small zooplankton, while adult sprats relied on large copepods and those of sardines and anchovies also consumed large portion of phytoplankton, confirming the high trophic plasticity of these two dominants small pelagic species. However, considering that anchovies have the greatest degree of trophic diversity compared with the other two species, they could be the most adapted to changing feeding conditions. The increase in sea temperatures that are reducing primary production and in turn zooplankton abundances, coupled with even more frequent extreme meteorologic events could exacerbate the competition for trophic resources among pelagic mesopredators, and could lead to more notable stocks' fluctuations and unpredictable wasp-waist effects.

Crowding in the middle of marine food webs: A focus on Raja asterias and other mediterranean batoids.

The Mediterranean Sea is among the three biodiversity hotspots of the world where elasmobranchs are severely threatened. Elasmobranchs act as apex or meso-predators within marine food webs and the loss/decline of apex predators determines the mesopredator release, leading in turn to increased predation on smaller prey. However, also several mesopredators (including rays, skates and small sharks) are intensively fished, being of commercial interest, or by-caught, and thus mesopredators increase could not be so evident. We analysed the trophic ecology of an endemic Mediterranean ray, the starry ray Raja asterias, at a seasonal scale from the Adriatic basin, one of the most intensively exploited area of the Mediterranean, by means of stomach contents and stable isotopes analyses. Our results evidenced that starry rays rely on benthic sources including species of local commercial values, such as swimming crabs, small cephalopods, and stomatopods and share the same trophic position with other elasmobranchs (rays, skates, and small sharks) and other mesopredators (e.g., common soles, Norway lobsters and mullets). As all mesopredators are overexploited, as well as their benthic prey are affected by intense trawl-fishing, the whole food webs are disrupted and neither the classical trophic cascade nor the mesopredator release hypothesis could be verified. Conservation measures for these species, such as the release after capture or the application of exclusion grids to the net, should be applied in areas where populations are strongly impacted by trawling.

Seasonal trophic ecology of the invasive crab Percnon gibbesi (Brachyura, Plagusiidae) in the southwestern mediterranean: Insights from stomach contents and stable isotope analyses.

The invasive sally lightfoot crab Percnon gibbesi (H. Milne Edwards, 1853) has spread among the coasts of the Mediterranean Sea, including the coasts of Annaba Gulf (Algeria). Investigating the trophic position of the species and looking for the seasonal variations in the diet of this alien decapod was the aim of this study. To do this, samples of P. gibbesi were collected along Annaba coasts within a year. The traditional stomach content analysis (SCA) was integrated to the stable isotope analysis (SIA) of nitrogen and carbon to provide a comprehensive evaluation of the feeding ecology of P. gibbesi, and its within-year variability. Results highlighted, for the first time, significant seasonal variation in P. gibbesi diet, improving our understanding of its trophic plasticity and potential dietary overlaps with other herbivore species. Its feeding plasticity is an asset in the successful expansion of its distribution. Relating its diet composition through the different seasons with the interactions with native herbivores will be essential to fully appreciate the impact of the spread of P. gibbesi in the Mediterranean Sea.

Exo-Ocean Exploration with Deep-Sea Sensor and Platform Technologies.

One of Saturn's largest moons, Enceladus, possesses a vast extraterrestrial ocean (i.e., exo-ocean) that is increasingly becoming the hotspot of future research initiatives dedicated to the exploration of putative life. Here, a new bio-exploration concept design for Enceladus' exo-ocean is proposed, focusing on the potential presence of organisms across a wide range of sizes (i.e., from uni- to multicellular and animal-like), according to state-of-the-art sensor and robotic platform technologies used in terrestrial deep-sea research. In particular, we focus on combined direct and indirect life-detection capabilities, based on optoacoustic imaging and passive acoustics, as well as molecular approaches. Such biologically oriented sampling can be accompanied by concomitant geochemical and oceanographic measurements to provide data relevant to exo-ocean exploration and understanding. Finally, we describe how this multidisciplinary monitoring approach is currently enabled in terrestrial oceans through cabled (fixed) observatories and their related mobile multiparametric platforms (i.e., Autonomous Underwater and Remotely Operated Vehicles, as well as crawlers, rovers, and biomimetic robots) and how their modified design can be used for exo-ocean exploration.

Towards an Ecosystem-Based Marine Spatial Planning in the deep Mediterranean Sea.

The deep sea covers about 79% of the Mediterranean basin, including habitats potentially able to deliver multiple ecosystem services and numerous resources of high economic value. Thus, the deep Mediterranean Sea represents an important frontier for marine resources exploitation, which is embedded within the European Blue Growth Strategy goals and agendas. The deep sea is crucial for the ecological functioning of the entire basin. For this reason, the deep Mediterranean deserves protection from the potential cumulative impacts derived from existent and developing human activities. Marine Spatial Planning (MSP) has been identified as key instrument for spatially allocating maritime uses in the sea space avoiding spatial conflicts between activities, and between activities and the environment. Indeed, MSP incorporates the ecosystem-based approach (EB-MSP) to balance both socio-economic and environmental objectives, in line with the Maritime Spatial Planning Directive and the Marine Strategy Framework Directive. Despite MSP is under implementation in Europe, the Directive is not applied yet for the managing and monitoring of the environmental status of the deep sea. In the Mediterranean, deep areas fall both in internal and territorial waters, and in High Seas, and its management framework turns out to be complicated. Moreover, a certain level of cumulative impacts in the deep Mediterranean has been already identified and likely underestimated because of paucity of knowledge related with deep-sea ecosystems. Thus, the implementation of scientific knowledge and the establishment of a sustainable management regime of deep-sea resources and space are urgent. This study aims at reflecting on the best available ecological knowledge on the deep Mediterranean to incorporate conservation objectives in EB-MSP. We propose a framework to include key ecological principles in the relevant phases of any EB-MSP processes taking in consideration existing socio-economic and conservation scenarios in the region. We add the uncertainty principle to reflect on the still unexplored and missing knowledge related to the deep Mediterranean. Here, we resume some guidelines to overcome limits and bottlenecks while ensuring protection of deep-sea ecosystems and resources in the Mediterranean Sea.

Characterization of a population of Pelodera strongyloides (Nematoda: Rhabditidae) associated with the beetle Lucanus ibericus (Coleoptera: Lucanidae) from Georgia.

During a field survey for entomopathogenic nematodes in Georgia, in the territory of Borjomi-Kharagauli, a nematode population was isolated from the body of single dead beetle of Lucanus ibericus Motschulsky 1845 (Coleoptera: Lucanidae). Based on morphological characters and molecular analyses, the nematode species is identical to Pelodera strongyloides (Schneider, 1860, 1866), being the first record of this species in Georgia. Morphometrics of the Georgian population agree with the original description, and females differ from males by very few characters. The Georgian population of P. strongyloides was molecularly characterized by sequencing the D2 to D3 expansion domains of the 28S rRNA gene and two new molecular markers as the ITS and the mitochondrial COI gene. Phylogenetic analyses revealed that all P. strongyloides sequences grouped together along with all other Pelodera species.

Detecting the occurrence of indigenous and non-indigenous megafauna through fishermen knowledge: A complementary tool to coastal and port surveys.

Marine bioinvasions and other rapid biodiversity changes require today integrating existing monitoring tools with other complementary detection strategies to provide a more efficient management. Here we explored the efficacy of fishermen observations and traditional port surveys to effectively track the occurrence of both indigenous and non-indigenous megafauna in the Adriatic Sea. This consisted mainly of mobile taxa such as fishes, crustaceans and molluscs. Port surveys using traps and nets within 10 major Adriatic harbours, were compared with the information obtained from 153 interviews with local fishermen. Information gathered by traps and nets varied significantly and generally resulted of limited efficacy in exotic species detection. Interviews allowed tracking the occurrence of new species through time and space, providing complementary knowledge at the low cost. This combined approach improves our capability of being informed on the arrival of species of different origin, providing a more rational, improved basis for environmental management and decision making.

Faunal activity rhythms influencing early community succession of an implanted whale carcass offshore Sagami Bay, Japan.

Benthic community succession patterns at whale falls have been previously established by means of punctual submersible and ROV observations. The contribution of faunal activity rhythms in response to internal tides and photoperiod cues to that community succession dynamism has never been evaluated. Here, we present results from a high-frequency monitoring experiment of an implanted sperm whale carcass in the continental slope (500 m depth) offshore Sagami Bay, Japan. The benthic community succession was monitored at a high frequency in a prolonged fashion (i.e. 2-h intervals for 2.5 months) with a seafloor lander equipped with a time-lapse video camera and an acoustic Doppler profiler to concomitantly study current flow dynamics. We reported here for the first time, to the best of our knowledge, the occurrence of strong 24-h day-night driven behavioral rhythms of the most abundant species (Simenchelys parasitica; Macrocheira kaempferi, and Pterothrissus gissu). Those rhythms were detected in detriment of tidally-controlled ones. Evidence of a diel temporal niche portioning between scavengers and predators avoiding co-occurrence at the carcass, is also provided. The high-frequency photographic and oceanographic data acquisition also helped to precisely discriminate the transition timing between the successional stages previously described for whale falls' attendant communities.

Inertial bioluminescence rhythms at the Capo Passero (KM3NeT-Italia) site, Central Mediterranean Sea.

In the deep sea, the sense of time is dependent on geophysical fluctuations, such as internal tides and atmospheric-related inertial currents, rather than day-night rhythms. Deep-sea neutrino telescopes instrumented with light detecting Photo-Multiplier Tubes (PMT) can be used to describe the synchronization of bioluminescent activity of abyssopelagic organisms with hydrodynamic cycles. PMT readings at 8 different depths (from 3069 to 3349 m) of the NEMO Phase 2 prototype, deployed offshore Capo Passero (Sicily) at the KM3NeT-Italia site, were used to characterize rhythmic bioluminescence patterns in June 2013, in response to water mass movements. We found a significant (p < 0.05) 20.5 h periodicity in the bioluminescence signal, corresponding to inertial fluctuations. Waveform and Fourier analyses of PMT data and tower orientation were carried out to identify phases (i.e. the timing of peaks) by subdividing time series on the length of detected inertial periodicity. A phase overlap between rhythms and cycles suggests a mechanical stimulation of bioluminescence, as organisms carried by currents collide with the telescope infrastructure, resulting in the emission of light. A bathymetric shift in PMT phases indicated that organisms travelled in discontinuous deep-sea undular vortices consisting of chains of inertially pulsating mesoscale cyclones/anticyclones, which to date remain poorly known.

Spatial variability of soft-bottom macrobenthic communities in northern Sicily (Western Mediterranean): Contrasting trawled vs. untrawled areas.

This study examines the impact of bottom trawl fishing on the macrobenthic communities inhabiting the coastal terrigenous mud off the northern coast of Sicily (Western Mediterranean). Two intensely trawled gulfs were compared with two gulfs from which trawling has been excluded for 15 years. The results show a significant effect of trawling on the faunal assemblage and when comparing the mean biomass and the whole isotopic composition of the benthic communities. A similar pattern, although not significant, was found for total abundance, biomass, production/biomass ratio and diversity. Higher abundance and lower biomass were found in the untrawled areas, attributable to the presence of more numerous yet smaller individuals, possibly a consequence of more abundant larger predators that are not removed by trawling, and consequent higher predatory pressure on the benthic macrofauna. The SIMPER analysis evidenced a dominance of burrowing deposit feeding worms (Paraonidae and Cossuridae) in trawled areas, as a result of increased mechanical alteration and hence more organic matter available as food. In contrast, the response to trawling as drawn by the use of trophic markers (i.e., stable isotopes) was less clear. While δ15N of benthic taxa did not vary significantly between untrawled and trawled areas, δ13C was higher in trawled areas possibly due to high sediment resuspension and consequent intense microbial activity. Mixing models confirmed higher reliance to a detritus-based food web for benthic organisms in the trawled areas. Standard Ellipse Areas (SEAc) as a measure of community niche width were slightly larger in trawled areas, likely due to higher generalism triggered by alteration/removal of the original benthic community.

Spatial variations in feeding habits and trophic levels of two small pelagic fish species in the central Mediterranean Sea.

Trophic ecology of adults of European sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) was examined and compared among various regions of central Mediterranean Sea. Carbon and nitrogen stable isotope analyses (δ(13)C and δ(15)N) were adopted as a tool to determine changes in feeding behaviour of adults of sardines and anchovies. In the study period (summer) a clear geographical pattern was recognized in the isotopic composition of both species, with an increasing trend northward. The highest variations in isotopic signal were linked to the geographical positions of the samples and, especially, between pairs of areas: South Sicily/South Campania and Gulf of Gaeta/South Elba. Higher isotope values were found in the anchovies and sardines caught in northern Tyrrhenian Sea, while lower values were mostly estimated in the southern region. Higher carbon and nitrogen isotopes may reflect a more coastal behaviour of both species, being (13)C-enriched source from benthic primary producers in addition to phytoplankton. Variations in the nitrogen isotope ratio may reflect not only differences in the trophic level of prey species, but also variations in the baseline level of food webs. Our results support the hypothesis that feeding behaviour of both species is directly or indirectly influenced by local factors, or by resource partitioning based on zooplankton size. Findings can supply knowledge needed for improving fish stock management and promoting plans able to take into account also local ecosystem analysis.

Trophic ecology of Lampanyctus crocodilus on north-west Mediterranean Sea slopes in relation to reproductive cycle and environmental variables.

This study examined the population structure, reproductive cycle and feeding pattern of the lanternfish Lampanyctus crocodilus in the Balearic Basin (north-west Mediterranean Sea) from a depth of 450 to 1800 m and at a seasonal scale. Juveniles were mainly located at shallower depths, but also at deepest stations in autumn, while adults mostly inhabited intermediate depths with their centre of population density (CPD) located at 800-1000 m of depth. The migration of adults to deeper depths was detected in late summer to autumn, probably linked to the occurrence of nepheloid layers at c. 1200 m, which in turn enhances the biomass of the zooplankton prey. The diet was mainly based on euphausiids and mysids, with marked seasonal variations both on the upper (450-800 m) and lower (1000-1800 m), where suprabenthic gammariids and pelagic decapods were also dominant. Stomach fullness increased from winter to autumn on the US, while it had a maximum in spring on the LS, in parallel with high consumption of gelatinous zooplankton, which is probably more available after the phytoplankton bloom in late winter. Reproduction occurred in winter, confirmed by the higher percentage of mature females and high gonadosomatic indices (I(G)) at both depth ranges. Hepatosomatic indices (I(H)) showed an inverse trend to I(G) on the US, except in autumn, and was almost parallel on the LS, probably attributable to the migration of adults, which determined different temporal schemes in energy use and storage for reproduction on the US v. LS. Consistent with the different patterns observed at the two depth ranges, environmental drivers of fullness (i.e. feeding intensity) and I(G) (as a proxy of reproductive cycle) differed on the US and LS. The biomass of mysids and euphausiids was the greatest explanatory variables of fullness on the US and LS, pointing to the increasing feeding intensity when a resource was more available. I(H) also explained fullness, suggesting that greater feeding intensity in pre-reproductive periods enabled energy storage in the liver. I(G) was linked directly (i.e. mysids) or indirectly (i.e. surface primary production recorded 2 months before sampling) to food availability, implying a rapid response to vertical food inputs by deep-sea predators. Also, I(G) in L. crocodilus was related to population density, which suggests aggregations for reproduction. Estimates of L. crocodilus trophic levels, and of other accompanying mesopelagic fishes, indicated that the species feed through a continuum spanning the third trophic level, confirming the key role of mesopelagic fishes in transferring organic carbon between trophic levels. Trophic niche segregation among mesopelagic species was pronounced and non-overlapping groups could be distinguished because of the different vertical distribution and migratory behaviour. The study highlights the important role of the benthic boundary layer in sustaining benthopelagic communities in the deep Mediterranean Sea and the need to study the biology of a species throughout its whole depth range and not just at exploited depths (i.e. fishing grounds).

Women and alcohol. A survey in the city of Barletta.

INTRODUCTION: The aim of this survey was to evaluate the qualitative and quantitative relationship among women from Barletta--a national renowned wine center--and their alcohol consumption. METHODS: The AUDIT questionnaire was used to assess the prevalence of alcohol hazardous consumption among women. Questionnaires were submitted from March to November 2012. The sample was composed of 150 women older than 13 years of age, selected by stratified sampling based on age group. RESULTS: 107 women were enrolled with a total response rate of 71.3%. 62% of enrolled women consumes alcoholic beverages with a frequency that goes from 2-3 times a week to less than once a month, usually 1 or 2 alcoholic units. The binge-drinking was reported by 5% of women. Women who reported alcohol-related risk behaviors were less than 3%, they were single and between 18 and 60 years old and such behaviors occur less than once a month. The final score, calculated for all the women from their questionnaire answers, was not higher than 8, with an average score of 1.3 (SD = 1.5; range: 0 to 2.8). The comparison of the average scores of the three age groups showed a statistically significant difference (F = 5.8, p = 0.004). DISCUSSION: Data from literature showed a change in the habits of alcohol intake by the global, European and also Italian population. These changes also affect and involve female. Our study found a quite moderate alcohol consumption among women from Barletta, with only 1% who consumes 3 or more alcohol units and drink more than four times a week and 3% who had hazardous behavior related to their alcohol consumption. Statistical significance was found for the age and the lack of stable relationships. The analysis of characteristics of at risk women (old age and single-status) suggests that much attention should be paid to them and they should represent the main subject of future social interventions to prevent alcohol related problems in the city of Barletta.

Biomass gasification and in-bed contaminants removal: performance of iron enriched olivine and bauxite in a process of steam/O2 gasification.

A modified Olivine, enriched in iron content (10% Fe/Olivine), and a natural bauxite, were tested in the in-bed reduction of tar and alkali halides (NaCl and KCl) released in a process of biomass steam/O(2) gasification. The tests were carried out at an ICBFB bench scale reactor under the operating conditions of: 855-890 °C, atmospheric pressure, 0.5 steam/biomass and 0.33 ER ratios. From the use of the two materials, a reduction in the contaminant contents of the fuel gas produced was found. For the alkali halides, a decrease up to 70%(wt) was observed for the potassium concentration, while for sodium, the reduction was found to be quite poor. For the organic content, compared to unmodified Olivine, the chromatographically determined total tar quantity showed a removal efficiency of 38%(wt). Moreover, regarding the particulate content a rough doubling in the fuel gas revealed a certain brittleness of the new bed material.

Food partitioning and diet temporal variation in two coexisting sparids, Pagellus erythrinus and Pagellus acarne.

Resource partitioning in two congeneric sparids, pandora Pagellus erythrinus and axillary seabream Pagellus acarne, was investigated using stomach content analysis integrated with data on stable isotopes (δ(15) N and δ(13) C). The study was carried out on coastal muddy bottoms in the Gulf of Castellammare (southern Tyrrhenian Sea, western Mediterranean Sea) in seasons (autumn, November 2004; winter, March 2005; spring, early June 2005), at depths between 50 and 100 m. Stomach content analysis suggested low trophic niche overlap between the two species. Pagellus erythrinus mainly preyed on strictly benthic organisms (polychaetes, brachyuran crabs and benthic crustaceans). Although it consumed benthic prey, P. acarne preferred suprabenthic prey such as peracarid crustaceans from the benthic boundary layer a few metres above the bottom. The two species showed different isotopic values, with P. erythrinus exhibiting higher δ(15) N and more enriched δ(13) C than P. acarne, in accordance with its marked benthic behaviour and high predation on carnivore polychaetes. Significant temporal variability in both diet and isotopic values caused trophic differences between the two species. The autumn and winter diet differed from the spring diet and the trophic levels of both species increased from autumn and winter to spring, in accordance with variations in food availability and changes in prey δ(15) N and δ(13) C. These temporal variations may be linked to an increase in energy requirements for reproduction, together with the differing availability of preferred prey throughout the year. Significantly, lower δ(13) C was recorded in fishes collected in winter (March), suggesting the influence of river inputs as a source of particulate organic matter in this zone after the flooding season. In conclusion, these sympatric congeneric fish species displayed clear food partitioning throughout the temporal scale analysed.

Phase transformations in bulk nanostructured potassium niobiosilicate glasses.

In potassium niobiosilicate (KNS) glasses, nanostructuring can be driven and controlled by thermal treatments at the glass transition temperature and/or by modulation of the chemical composition. The tight relationship between nanostructure and nonlinear optical properties suggests these bulk nanomaterials as an appealing route to nanophotonics. The focus of this paper is placed on assessing the phase transformations which occur in these materials upon annealing at the glass transition temperature and subsequent heating. High-temperature resolved X-ray diffraction (HTXRD) and high-resolution transmission electron microscopy (HRTEM) experiments are integrated with previously published results for in-depth insight. It will be shown that nanostructuring evolves from nucleation of niobium-rich nanocrystals, which are up to 20 nm large, uniformly distributed in the matrix bulk, and metastable. Formation kinetics as well as phase transformation of the nanocrystals are determined by the glass composition. Depending on it, nanocrystal nucleation can be preceded or not by phase separation, and the nanocrystals' phase transition can be of first or second order.

Monitoring the Prestige oil spill impacts on some key species of the Northern Iberian shelf.

Selected key components of the continental shelf benthic and demersal communities were monitored for the two years following the Prestige oil spill (POS) in order to identify the possible ecological effects of the oil. This work includes the first results regarding changes in abundance, distribution and food habits of hake (Merluccius merluccius), four-spot megrim (Lepidorhombus boscii), Norway lobster (Nephrops norvegicus) and Pandalid shrimp (Plesionika heterocarpus) populations of Galician and Cantabrian Sea shelves following the POS. Significant reductions in the abundance of Norway lobster, Plesionika heterocarpus and four-spot megrim were detected in the POS maximum impact area, located over the Galician shelf. Noteworthy recoveries were observed in the 2004 abundance indices of four-spot megrim and Plesionika. On the other hand, no significant effects were detected in the abundance or distribution of hake juveniles even though the tar aggregates were bound by the same oceanographic drift events as the hake recruits were during the winter of 2003 (Navidad current) in different water column layers of the Cantabrian Sea. Feeding patterns of the four species analysed did not present apparent modifications that can be related to the POS.

Studies on the role of serotonin receptor subtypes in the effect of sibutramine in various feeding paradigms in rats.

The effect of the 5-hydroxytryptamine (5-HT) and noradrenaline (NA) reuptake inhibitor sibutramine was studied in food deprived, neuropeptide Y (NPY)- or muscimol-injected rats. Sibutramine dose-dependently reduced feeding caused by food-deprivation (ED50 = 5.1+/-0.8 mg kg(-1)) or by NPY injection into the paraventricular nucleus of the hypothalamus (ED50 = 6.0+/-0.5 mg kg(-1)). The increase in food intake caused by muscimol injected into the dorsal raphe was not modified by sibutramine (1-10 mg kg(-1)). The hypophagic effect of 5.1 mg kg(-1) sibutramine in food-deprived rats was studied in rats pretreated with different serotonin receptor antagonists. Metergoline (non-selective, 0.3 and 1.0 mg kg(-1)), ritanserin (5-HT2A/2C, 0.5 and 1.0 mg kg(-1)) and GR127935 (5-HT1B/1D), 0.5 and 1.0 mg kg(-1)) did not modify the hypophagic effect of sibutramine, while SB206553 (5-HT2B/2C, 5 and 10 mg kg(-1)) slightly but significantly reduced it (Fint(2.53) = 3.4; P<0.05). The reduction in food intake caused by 6.0 mg kg(-1) sibutramine in NPY-injected rats was not modified by GR127935 (1.0 mg kg(-1)). The results suggest that, with the possible exception of a partial involvement of 5-HT2B/2C receptors in sibutramine's hypophagia in food-deprived rats, 5-HT1 and 5-HT2 receptor subtypes do not play an important role in the hypophagic effect of sibutramine, at least in the first 2 h after injection.

Citalopram-induced hypophagia is enhanced by blockade of 5-HT(1A) receptors: role of 5-HT(2C) receptors.

The selective 5-hydroxytryptamine reuptake inhibitor citalopram (10 and 20 mg kg(-1), i.p.) significantly reduced food intake in male rats (CD-COBS) habituated to eat their daily food during a 4-h period. The 5-HT1A receptor antagonist WAY100635 (0.3 mg kg(-1)) administered systemically did not modify feeding but significantly potentiated the reduction in food intake caused by 10 mg kg(-1) i.p. citalopram. The dose of 5 mg kg(-1) i.p. citalopram was not active in animals pretreated with vehicle but significantly reduced feeding in animals pretreated with WAY100635. WAY100635 (0.1 microg 0.5 microl(-1)) injected into the dorsal raphe significantly potentiated the hypophagic effect of 10 mg kg(-1) citalopram. WAY100635 (1.0 microg 0.5 microl(-1)) injected into the median raphe did not modify feeding or the hypophagic effect of 10 mg kg(-1) citalopram. The 5-HT2B/2C receptor antagonist SB206553 (10 mg kg(-1), p.o.) slightly reduced feeding by itself but partially antagonized the effect of WAY100635 administered systemically (0.3 mg kg(-1), s.c.) or into the dorsal raphe (0.1 microg 0.5 microl(-1)) in combination with 10 mg kg(-1) i.p. citalopram. The hypophagic effect of 10 mg kg(-1) i.p. citalopram alone was not significantly modified by SB206553. Brain concentrations of citalopram and its metabolite desmethylcitalopram in rats pretreated with SB206553, WAY100635 and their combination were comparable to those of vehicle-pretreated rats, 90 min after citalopram injection. The hypophagic effect of citalopram was potentiated by blocking 5-HT1A receptors. Only the effect of the WAY100635/citalopram combination seemed to be partially mediated by central 5-HT2C receptors.