The avian community of the Karen Mogensen Reserve, a wealth of biodiversity within the poorly investigated and threatened environments of northwestern Costa Rica.

Despite being characterized by some of the most threatened forest ecosystems of Mesoamerica, the Nicoya Peninsula is among the least known regions of neotropical Costa Rica in terms of its birdlife. Within this region, in the framework of an ongoing international cooperation program between Italy and Costa Rica, we had the opportunity to investigate the Karen Mogensen Reserve, a protected area distinguished by the presence of a variety of habitats, including tropical dry forest and moist forest. Species richness in the Reserve was relatively high compared with similar areas in northwestern Costa Rica. A series of surveys carried out over a 20-year period documented an avian community consisting of 207 species, of which 115 were breeding in the zone and another 14 were potentially breeding. We recorded five IUCN globally Vulnerable or Near-Threatened species, along with six species reported for the first time from the Nicoya Peninsula, each representing range extension of more than 100 km. Twenty-six species, mostly breeding in the area, are at their southernmost range borders, and are likely susceptible to global environmental alterations, such as the effects of climate change. Furthermore, our study revealed the presence of two species endemic to a restricted area of Central America and four subspecies endemic to Costa Rica, along with breeding populations of two species that are geographically isolated from the main ones. The present analysis led to the ecological characterization of the resident avian community, showing that 65% of the species are strictly associated with forested environments, and especially with the understory or middle tree level, hence more vulnerable to environmental change (climatic, anthropogenic, etc.) and susceptible to local extinction. These results underscore the importance of the Karen Mogensen Reserve for bird conservation within a vulnerable environmental context, and warrant the continuation of periodic bird surveys, taxonomic study of isolated populations or endemic taxa, and improvement of local conservation measures. The data collected will be an important tool for future studies aimed at evaluating the consequences of habitat fragmentation and to monitor the effects of climate change on the resident avifauna. We exhort the creation of programs that integrate bird monitoring, ecological research, conservation initiatives, and the involvement of the local communities, by promoting environmental education, capacity-building, and income generation. To this purpose, the Karen Mogensen Reserve may represent a convincing model and valuable example to apply in similar neotropical contexts.

Endoreplication: a molecular trick during animal neuron evolution.

The occurrence of endoreplication has been repeatedly reported in many organisms, including protists, plants, worms, arthropods, molluscs, fishes, and mammals. As a general rule, cells possessing endoreplicated genomes are large-sized and highly metabolically active. Endoreplication has not been frequently reported in neuronal cells that are typically considered to be fully differentiated and non-dividing, and which normally contain a diploid genome. Despite this general statement, various papers indicate that giant neurons in molluscs, as well as supramedullary and hypothalamic magnocellular neurons in fishes, contain DNA amounts larger than 2C. In order to study this issue in greater detail here, we review the available data about endoreplication in invertebrate and vertebrate neurons, and discuss its possible functional significance. As a whole, endoreplication seems to be a sort of molecular trick used by neurons in response to the high functional demands that they experience during evolution.

Restraint stress alters the secretory activity of neurons co-expressing urocortin-1, cocaine- and amphetamine-regulated transcript peptide and nesfatin-1 in the mouse Edinger-Westphal nucleus.

Central stress regulatory pathways utilize various neuropeptides, such as urocortin-1 (Ucn1) and cocaine- and amphetamine-regulated transcript peptide (CART). Ucn1 is most abundantly expressed in the non-preganglionic Edinger-Westphal nucleus (npEW). In addition to Ucn1, CART and nesfatin-1 are highly expressed in neurons of the npEW, but the way these three neuropeptides act together in response to acute stress is not known. We hypothesized that Ucn1, CART and nesfatin-1 are colocalized in npEW neurons and that these neurons are recruited by acute stress. Using quantitative immunocytochemistry and the reverse transcriptase polymerase chain reaction (RT-PCR), we support this hypothesis, by showing in B6C3F1/Crl mice that Ucn1, CART and nesfatin-1 occur in the same neurons of the npEW nucleus. More specifically, Ucn1 and CART revealed a complete colocalization in the same perikarya, while 90% of these neurons are also nesfatin-1-immunoreactive. Furthermore, acute (restraint) stress stimulates the general secretory activity of these npEW neurons (increased presence of Fos) and the production of Ucn1, CART and nesfatin-1: Ucn1, CART and nesfatin-1(NUCB2) mRNAs have been increased compared to controls by x1.8, x2.0 and x2.6, respectively (p<0.01). We conclude that Ucn1, CART and nesfatin-1/NUCB2 are specifically involved in the response of npEW neurons to acute stress in the mouse.

Tyrosine and tyramine increase endogenous ganglionic morphine and dopamine levels in vitro and in vivo: cyp2d6 and tyrosine hydroxylase modulation demonstrates a dopamine coupling.

BACKGROUND: The ability of animals to make morphine has been in question for the last 30 years. Studies have demonstrated that animals do contain morphine precursors and metabolites, as well as the ability to use some morphine precursors to make morphine. MATERIAL/METHODS: The present study uses excised ganglia from the marine invertebrate Mytilus edulis as well as whole animals. Morphine and dopamine levels were determined by high performance liquid chromatography coupled to electrochemical detection and radioimmunoassay. Tissues and whole animals were also exposed to morphine precursors and exposed to the CYP2D6 inhibitor quinidine and the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine (AMPT). Additionally, via RT-PCR, a cDNA fragment of the CYP2D6 enzyme in the ganglia of M. edulis was identified. RESULTS: Pedal ganglia incubated with either tyramine or tyrosine, or whole animals receiving injections, exhibited a statistically significant concentration- and time-dependent increase in their endogenous morphine and dopamine levels (2.51 +/- 0.76 ng/g for tyrosine and 2.39 +/- 0.64 ng/g for tyramine compared to approximately 1.0 ng/g morphine wet weight). Incubation with quinidine and/or AMPT diminished ganglionic morphine and dopamine synthesis at various steps in the synthesis process. We also demonstrated that CYP2D6 mediates the tyramine to dopamine step in this process, as did tyrosine hydroxylase in the step from tyrosine to L-DOPA. Furthermore, via RT-PCR, we identified a cDNA fragment of the CYP2D6 enzyme in the ganglia, which exhibits 94% sequence identity with its human counterpart. Evidence that tyrosine and tyramine were, in part, being converted to dopamine then morphine, and that this process can be inhibited by altering either or both CYP2D6 or tyrosine hydroxylase, is also provided. CONCLUSIONS: It appears that animals have the ability to make morphine. This process also appears to be dynamic in that the inhibition of one pathway allows the other to continue with morphine synthesis. Moreover, dopamine and morphine synthesis were coupled.

Endogenous morphine and ACTH association in neural tissues.

BACKGROUND: Endogenous morphine and proopiomelanocortin-derived peptide-like molecules were identified in molluscan tissues, including the nervous system, supporting their ancient phylogeny. Their presence and function in "simple" animals, demonstrates their involvement in mechanisms underlying the stress response, preceding the mammalian neuroendocrine axis. MATERIAL/METHODS: Immunocytochemical analysis was used to study the localization of morphine- and adrenocorticotropic hormone (ACTH)-like material in the nervous system of Planorbarius corneus, Mytilus galloprovincialis, Lymnaea stagnalis and Viviparus ater. Acute stress experiments were performed on P. corneus and, by radioimmune assay, we quantified the expression of an ACTH-like peptide in control and stressed animals. RESULTS: We demonstrate that in mollusks the presence of a morphine-like compound is differentially distributed in neuronal structures containing an ACTH-like molecule. In P. corneus, the two immunoreactivities appear to be colocalized in neuronal bodies and axonal endings, suggesting a role in neurotransmission/neuromodulation. We also found that these molecules are released in the hemolymph, suggesting neuroendocrine-immunoregulatory communication. Comparative studies on the other mollusks gave different distribution pictures of the two immunoreactivities. In P. corneus, following experimental trauma, the levels of both the messengers increase in ganglia and hemolymph at different times, which can be related to their postulated roles. CONCLUSIONS: In mollusks more than in mammals, there is a diversified but close association between morphine and ACTH, both acting in a stress response possibly exerting reciprocal influences, suggesting that the relationship evolved in invertebrates and was conserved during evolution.

Endogenous morphine and codeine in the brain of non human primate.

BACKGROUND: Morphine is the most used compound among narcotic analgesics. Apart from its presence in the poppy plant, morphine has been shown to be endogenously present in different tissues of mammals and lower animals. MATERIAL/METHODS: The presence of endogenous morphine and codeine was investigated by Gas Chromatography/ Mass Spectrometry (GC/MS) in the brain of non human primate. The release of endogenous morphine from monkey brain slices was studied in vitro in the presence of high potassium concentrations with and without calcium in the medium. RESULTS: Endogenous morphine, and its direct precursor codeine, was for the first time detected by GC/MS in the brain of non human primate. High potassium concentrations depolarized neurons releasing endogenous morphine twofold above basal line levels in a calcium dependent mechanism. CONCLUSIONS: This finding confirms the presence of the endogenous alkaloid throughout the phylogenesis of the nerve system of mammals and lower animals and indicates that endogenous morphine might function as a neuromodulator/neurotransmitter agent in the central nervous system (CNS) of non human primates.

Presence and role of nitric oxide in the central nervous system of the freshwater snail Planorbarius corneus: possible implication in neuron-microglia communication.

The aim of the present study was to investigate the involvement of nitric oxide (NO) as a messenger molecule in neuron-microglia communication in the central nervous system (CNS) of the freshwater snail Planorbarius corneus. The presence of both neuronal (nNOS) and inducible nitric oxide synthase (iNOS) was studied using NADPH-diaphorase (NADPH-d) histochemistry and NOS immunocytochemistry. The experiments were performed on whole ganglia and cultured microglial cells after different activation modalities, such as treatment with lipopolysaccharide and adenosine triphosphate and/or maintaining ganglia in culture medium till 7 days. In sections, nNOS immunoreactivity was found only in neurons and nNOS-positive elements were less numerous than NADPH-d-positive ones, with which they partially overlapped. The iNOS immunoreactivity was observed only after activation, in both nerve and microglial cells. We also found that the number of iNOS-immunoreactive neurons and microglia varied, depending on the activation modalities. In microglial cell cultures, iNOS was expressed in the first generation of cells only after activation, whereas a second generation, proliferated after ganglia activation, expressed iNOS even in the unstimulated condition.

Distribution of sensorin immunoreactivity in the central nervous system of Helix pomatia: functional aspects.

Land snails belonging to the genus Helix are commonly used to study several behaviors and their plasticity at the cellular level. Because the knowledge of sensory neurons in these species is far from being complete, we have investigated the presence and distribution in Helix pomatia central nervous system of the immunoreactivity for sensorin, a peptide specific for mechanosensory neurons in Aplysia. We found that the majority of immunopositive cells were grouped in clusters located in all the central ganglia, except for the pedal ganglion, where only a single large neuron was stained. A symmetrical cluster of stained cells in the cerebral ganglia showed homology with the cerebral J clusters in Aplysia. Most of the somata of these Helix cerebral clusters send their axons in the ipsilateral cerebropedal connective and lip nerves and make monosynaptic connections with cells located in a medial adjacent cluster. This monosynaptic circuit can be reestablished in culture, where it shows homosynaptic depression as it does in the ganglionic preparation.