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1.
Ecology ; 103(10): e3775, 2022 10.
Article in English | MEDLINE | ID: mdl-35661139

ABSTRACT

Managing wildlife populations in the face of global change requires regular data on the abundance and distribution of wild animals, but acquiring these over appropriate spatial scales in a sustainable way has proven challenging. Here we present the data from Snapshot USA 2020, a second annual national mammal survey of the USA. This project involved 152 scientists setting camera traps in a standardized protocol at 1485 locations across 103 arrays in 43 states for a total of 52,710 trap-nights of survey effort. Most (58) of these arrays were also sampled during the same months (September and October) in 2019, providing a direct comparison of animal populations in 2 years that includes data from both during and before the COVID-19 pandemic. All data were managed by the eMammal system, with all species identifications checked by at least two reviewers. In total, we recorded 117,415 detections of 78 species of wild mammals, 9236 detections of at least 43 species of birds, 15,851 detections of six domestic animals and 23,825 detections of humans or their vehicles. Spatial differences across arrays explained more variation in the relative abundance than temporal variation across years for all 38 species modeled, although there are examples of significant site-level differences among years for many species. Temporal results show how species allocate their time and can be used to study species interactions, including between humans and wildlife. These data provide a snapshot of the mammal community of the USA for 2020 and will be useful for exploring the drivers of spatial and temporal changes in relative abundance and distribution, and the impacts of species interactions on daily activity patterns. There are no copyright restrictions, and please cite this paper when using these data, or a subset of these data, for publication.


Subject(s)
COVID-19 , Animals , Animals, Wild , Birds , COVID-19/epidemiology , Humans , Mammals , Pandemics , United States
2.
J Membr Biol ; 255(1): 41-53, 2022 02.
Article in English | MEDLINE | ID: mdl-34546414

ABSTRACT

Ligands of high specificity and selectivity have been selected for biological molecules of interest including nicotinic acetylcholine receptor (nAChR) using combinatorial libraries of nucleic acids. The nAChR belongs to a group of structurally related proteins that regulate signal transmission between ~ 1012 cells of the mammalian nervous system. It is inhibited by both therapeutic agents and abused drugs, including cocaine. A mechanism-based approach to alleviating noncompetitive inhibition of the mucle-type nAChR, including Torpedo, resulted in the selection of very short DNA aptamers only seven nucleotides long. By transient kinetic measurements, these DNA aptamers, which displaced cocaine from its binding site on the muscle-type nAChR, were classified into two groups based on their effects on the nAChR: Class I aptamers inhibit agonist-induced current in the muscle-type nAChR and Class II molecules alleviate inhibition by MK-801 [(+)-dizocilpine] without affecting the receptor function. The most potent Class I DNA aptamer, which inhibits the muscle-type nAChR, has an apparent dissociation constant (KIapt) of 5 µM, while the most efficient Class II DNA aptamer, which alleviates MK-801-induced inhibition, has an apparent dissociation constant (KApt) of 1.8 µM. An innovative aspect of the work is the identification of very short DNA aptamers with these properties that makes them attractive for therapeutic and diagnostic applications.


Subject(s)
Aptamers, Nucleotide , Cocaine , Receptors, Nicotinic , Animals , Aptamers, Nucleotide/pharmacology , Cell Line , Cocaine/chemistry , Cocaine/pharmacology , Dizocilpine Maleate/pharmacology , Mammals/metabolism , Muscles/metabolism , Receptors, Nicotinic/chemistry
3.
Ecology ; 102(7): e03372, 2021 07.
Article in English | MEDLINE | ID: mdl-33866560

ABSTRACT

Camera trap surveys are useful to understand animal species population trends, distribution, habitat preference, behavior, community dynamics, periods of activity, and species associations with environmental conditions. This information is ecologically important, because many species play important roles in local ecosystems as predators, herbivores, seed dispersers, and disease vectors. Additionally, many of the larger wildlife species detected by camera traps are economically important through hunting, trapping, or ecotourism. Here we present a data set of camera-trap surveys from 6,043 locations across all 100 counties of North Carolina, USA from 2009 to 2019. These data come from 26 survey initiatives and contain 215,108 records of 36 mammal species and three species of terrestrial birds. This large data set increases the geographical distribution data for these 39 mammal and bird species by >500% over what is available for North Carolina in the Global Biodiversity Information Facility (GBIF). These data can be used to conduct inquiries about species, populations, communities, or ecosystems, and to produce useful information on wildlife behavior, distribution, and interactions. There are no copyright restrictions. Please cite this paper when using the data for publication.


Subject(s)
Animals, Wild , Ecosystem , Animals , Biodiversity , Mammals , North Carolina
4.
Ecology ; 102(6): e03353, 2021 06.
Article in English | MEDLINE | ID: mdl-33793977

ABSTRACT

With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August-24 November of 2019). We sampled wildlife at 1,509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the United States. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as will future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.


Subject(s)
Animals, Wild , Mammals , Animals , Birds , Population Dynamics , United States
5.
J Wildl Dis ; 56(4): 791-802, 2020 10 01.
Article in English | MEDLINE | ID: mdl-32320341

ABSTRACT

The North American river otter (Lontra canadensis) is the largest mustelid in North Carolina, US, and was once extirpated from the central and western portions of the state. Over time and after a successful reintroduction project, otters are now abundant and occur throughout North Carolina. However, there is a concern that diseases may have an impact on the otter population, as well as on other aquatic mammals, either through exposure to emerging diseases, contact with domestic animals such as domestic cats (Felis catus), or less robust condition of individuals through declines in water quality. We tested brain and kidney tissue from harvested otters for the pathogens that cause leptospirosis, parvovirus, and toxoplasmosis. Leptospirosis and toxoplasmosis are priority zoonoses and are maintained by domestic and wild mammals. Although parvovirus is not zoonotic, it does affect pets, causing mild to fatal symptoms. Across the 2014-15 and 2015-16 trapping seasons, we tested 220 otters (76 females, 144 males) using real-time PCR for Leptospira interrogans, parvovirus, and Toxoplasma gondii. Of the otters tested, 1% (3/220) were positive for L. interrogans, 19% (41/220) were positive for parvovirus, and 24% (53/220) were positive for T. gondii. Although the pathogens for parvovirus and toxoplasmosis are relatively common in North Carolina otters, the otter harvest has remained steady and the population appears to be abundant and self-sustaining. Therefore, parvovirus and toxoplasmosis do not currently appear to be negatively impacting the population. However, subsequent research should examine transmission parameters between domestic and wild species and the sublethal effects of infection.


Subject(s)
Leptospirosis/veterinary , Otters , Parvoviridae Infections/veterinary , Parvovirus/isolation & purification , Toxoplasmosis, Animal/epidemiology , Animals , Female , Leptospira/isolation & purification , Leptospirosis/epidemiology , Leptospirosis/microbiology , Male , North Carolina/epidemiology , Otters/microbiology , Otters/parasitology , Otters/virology , Parvoviridae Infections/epidemiology , Parvoviridae Infections/virology , Toxoplasma/isolation & purification , Toxoplasmosis, Animal/parasitology , Zoonoses
6.
Environ Monit Assess ; 192(2): 146, 2020 Jan 28.
Article in English | MEDLINE | ID: mdl-31993757

ABSTRACT

Aquatic apex predators are vulnerable to environmental contaminants due to biomagnification. North American river otter (Lontra canadensis) populations should be closely monitored across their range due to point and nonpoint pollution sources. Nonetheless, no information exists on environmental contaminants in the North Carolina otter population. Metals and metalloids occur naturally across the landscape, are essential for cellular function, and become toxic when concentrated unnaturally. We conducted our study across the three Furbearer Management Units (FMU) and 14 river basins of North Carolina. We determined the concentrations of arsenic, cadmium, calcium, cobalt, copper, iron, lead, magnesium, manganese, mercury, molybdenum, selenium, thallium, and zinc in liver and kidney samples from 317 otters harvested from 2009 to 2016. Arsenic, lead, and thallium samples were tested at levels below the limit of detection. With the exception of cadmium, we detected all other elements at higher levels in the liver compared with the kidney. Specifically, cadmium, cobalt, copper, iron, magnesium, manganese, mercury, molybdenum, and zinc levels differed by tissue type analyzed. Most element concentrations remained stable or increased with otter age. We detected higher levels of mercury and selenium in the Lower Pee Dee and Cape Fear river basins. River basins within the Mountain FMU were higher in cadmium, copper, iron, lead, and zinc, whereas the Coastal Plain FMU was lower in cobalt and manganese. None of the elements occurred at toxic levels. Our research establishes baseline concentration levels for North Carolina, which will benefit future monitoring efforts and provide insight into future changes in the otter population.


Subject(s)
Mercury , Otters , Animals , Environmental Monitoring , Mercury/analysis , Metals , North Carolina
7.
PLoS One ; 14(1): e0210149, 2019.
Article in English | MEDLINE | ID: mdl-30608960

ABSTRACT

Education may encourage personal and collective responses to climate change, but climate education has proven surprisingly difficult and complex. Self-perception of knowledge and intelligence represent one factor that may impact willingness to learn about climate change. We explored this possibility with a case study in Raleigh, North Carolina in 2015 (n = 200). Our goal was to test how gender and ethnicity influenced perceptions people had of their own climate change knowledge. Survey respondents were asked how strongly they agreed with the statement "I feel knowledgeable about climate change" (1 = strongly disagree, and 5 = strongly agree). Our survey instrument also included demographic questions about race, age, income, gender, and education, as well as respondent's experience with natural disasters and drought. We observed an interaction between education and gender where women's self-perceived knowledge was higher than men among people with low levels of educational attainment, but was higher for men than women among people with high levels of educational attainment. In addition, minority respondents self-reported lower perceived climate change knowledge than white respondents, regardless of educational attainment. This study enhances our understanding of the gender gap in self-perceptions of climate knowledge by suggesting it is contingent on educational attainment. This could be the result of stereotype-threat experienced by women and minorities, and exacerbated by educational systems. Because people who question their knowledge are often more able to learn, particularly in ideologically charged contexts, highly educated women and minorities may be more successful learning about climate change than white men.


Subject(s)
Climate Change , Educational Status , Self Concept , Adult , Aged , Aged, 80 and over , Culture , Female , Humans , Male , Middle Aged , Minority Groups/psychology , Minority Groups/statistics & numerical data , North Carolina , Sex Factors , Socioeconomic Factors , Stereotyped Behavior , Surveys and Questionnaires/statistics & numerical data , Young Adult
9.
Environ Manage ; 58(1): 15-30, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27094440

ABSTRACT

Impervious surfaces degrade urban water quality, but their over-coverage has not explained the persistent water quality variation observed among catchments with similar rates of imperviousness. Land-cover patterns likely explain much of this variation, although little is known about how they vary among watersheds. Our goal was to analyze a series of urban catchments within a range of impervious cover to evaluate how land-cover varies among them. We then highlight examples from the literature to explore the potential effects of land-cover pattern variability for urban watershed management. High-resolution (1 m(2)) land-cover data were used to quantify 23 land-cover pattern and stormwater infrastructure metrics within 32 catchments across the Triangle Region of North Carolina. These metrics were used to analyze variability in land-cover patterns among the study catchments. We used hierarchical clustering to organize the catchments into four groups, each with a distinct landscape pattern. Among these groups, the connectivity of combined land-cover patches accounted for 40 %, and the size and shape of lawns and buildings accounted for 20 %, of the overall variation in land-cover patterns among catchments. Storm water infrastructure metrics accounted for 8 % of the remaining variation. Our analysis demonstrates that land-cover patterns do vary among urban catchments, and that trees and grass (lawns) are divergent cover types in urban systems. The complex interactions among land-covers have several direct implications for the ongoing management of urban watersheds.


Subject(s)
Conservation of Natural Resources/methods , Urbanization/trends , Water Quality , Water Resources/supply & distribution , North Carolina , Poaceae/growth & development , Trees/growth & development
11.
J Chem Phys ; 143(11): 114702, 2015 Sep 21.
Article in English | MEDLINE | ID: mdl-26395723

ABSTRACT

Infrared reflection absorption spectroscopy is used to study the evolution of binary physisorbed films on graphite. A predeposited monolayer of SF6 is exposed to slowly increasing pressure of CF4 at constant temperature between 80 and 113 K. Shifts in the frequencies of the dominant vibrational mode of each species due to resonant dipole-dipole coupling serve as proxies for the areal density of each species in the monolayer. If the initial SF6 film is far below saturation (coexistence with bulk solid), the SF6 can be largely displaced by continuous solution of CF4. However, if the initial SF6 layer is at or near saturation, a layer of CF4 condenses on top at a well defined CF4 pressure after only 2%-3% dilution of the SF6 layer. Simultaneously, most of the dissolved CF4 is withdrawn from the SF6 layer. With further increase in CF4 pressure, the CF4 layer is compressed and additional layers condense, while the SF6 layer is again diluted. Still, the SF6 layer retains about 90% concentration until the CF4 pressure is very close to saturation, at which point the SF6 is rapidly displaced, apparently going into dilute solution in the rapidly growing CF4 multilayer. Monte Carlo simulations are used to quantitatively relate measured frequency shifts to concentrations in the binary monolayer.

12.
PLoS One ; 10(8): e0136973, 2015.
Article in English | MEDLINE | ID: mdl-26317355

ABSTRACT

Many global challenges, including obesity, health care costs, and climate change, could be addressed in part by increasing the use of bicycles for transportation. Concern about the safety of bicycling on roadways is frequently cited as a deterrent to increasing bicycle use in the USA. The use of effective signage along roadways might help alleviate these concerns by increasing knowledge about the rights and duties of bicyclists and motorists, ideally reducing crashes. We administered a web-based survey, using Twitter for recruitment, to examine how well three US traffic control devices communicated the message that bicyclists are permitted in the center of the travel lane and do not have to "get out of the way" to allow motorists to pass without changing lanes: "Bicycles May Use Full Lane" and "Share the Road" signage, and Shared Lane Markings on the pavement. Each was compared to an unsigned roadway. We also asked respondents whether it was safe for a bicyclist to occupy the center of the travel lane. "Bicycles May Use Full Lane" signage was the most consistently comprehended device for communicating the message that bicyclists may occupy the travel lane and also increased perceptions of safety. "Share the Road" signage did not increase comprehension or perceptions of safety. Shared Lane Markings fell somewhere between. "Bicycles May Use Full Lane" signage showed notable increases in comprehension among novice bicyclists and private motor vehicle commuters, critical target audiences for efforts to promote bicycling in the USA. Although limited in scope, our survey results are indicative and suggest that Departments of Transportation consider replacing "Share the Road" with "Bicycles May Use Full Lane" signage, possibly combined with Shared Lane Markings, if the intent is to increase awareness of roadway rights and responsibilities. Further evaluation through virtual reality simulations and on-road experiments is merited.


Subject(s)
Automobile Driving/psychology , Bicycling/psychology , Automobile Driving/legislation & jurisprudence , Bicycling/legislation & jurisprudence , Environment Design , Humans , Safety , Surveys and Questionnaires , United States
13.
Cold Spring Harb Protoc ; 2014(10): pdb.prot084160, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-25275111

ABSTRACT

Various devices have been used to flow neurotransmitter solutions over cells containing receptors (e.g., ligand-gated ion channels) for whole-cell current recordings. With many of the devices, the orientation between the porthole of the flow device and the cell is not maintained absolutely constant. Orientation is critical for reproducibility in kinetic experiments. To be able to change the composition of the flowing solution during an experiment and still maintain a constant orientation, we use the cell-flow device described here. A peristaltic pump, a stainless steel U-tube, two different sizes of peristaltic tubing, and a solenoid valve are required to create a simple solution exchange system that can rapidly apply and remove solutions over the surface of a cell in tens of milliseconds. This system allows one to test multiple conditions on a cell containing the receptor of interest while constantly "washing" the cell with extracellular buffer solution between experimental applications. The use of the solenoid valve allows for the application of solutions to be precisely timed and controlled by a computer during electrophysiological current recording.


Subject(s)
Action Potentials/drug effects , Electrophysiology/methods , Pulsatile Flow , Solutions/administration & dosage , Action Potentials/physiology , Animals , Cells, Cultured , Electrophysiology/instrumentation , Humans , Infusion Pumps, Implantable , Kinetics , Neurotransmitter Agents/administration & dosage , Patch-Clamp Techniques , Rats
14.
Cold Spring Harb Protoc ; 2014(10): pdb.top084152, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-25275116

ABSTRACT

The approaches using caged neurotransmitters described here enable transient kinetic investigations to be made with membrane-bound proteins (receptors) on a cell surface with the same time resolution as was previously possible only with proteins in solution.


Subject(s)
Neurons/physiology , Neurotransmitter Agents/metabolism , Photochemistry/methods , Photolysis , Animals , Cells, Cultured , Humans , Neurons/drug effects , Neurotransmitter Agents/chemistry , Receptors, Neurotransmitter/metabolism
15.
J Chem Phys ; 140(19): 194703, 2014 May 21.
Article in English | MEDLINE | ID: mdl-24852553

ABSTRACT

We report an experimental study of physisorbed monolayers and bilayers of CF4 on graphite using infrared reflection absorption spectroscopy supplemented by ellipsometry. The symmetric C-F stretch mode ν3 near 1283 cm(-1) in the gas is strongly blue shifted in the film by dynamic dipole coupling. This blue shift provides a very sensitive measure of the inter-molecular spacing in the monolayer and, less directly, in the bilayer. We find that important corrections are necessary to the volumetric coverage scales used in previous heat capacity and x-ray diffraction studies of this system. This requires quantitative and some qualitative changes to the previously proposed phase diagram. We find evidence for a new phase transition in the middle of the hexagonal incommensurate region and construct new phase diagrams in both the variables coverage-temperature and chemical potential-temperature. We determine the compressibility and thermal expansion in the low-pressure hexagonal incommensurate phase and values for the entropy change in several phase transitions. Below about 55 K there is evidence of solution of up to 7% of an impurity, most likely CO, in our monolayer but not the bilayer film.

16.
Conserv Biol ; 26(1): 7-12, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22044678

ABSTRACT

In the United States local land trusts preserve and conserve land to protect water quality and supply, farmlands, habitat for native plants and animals, areas of cultural or historical significance, and scenic views. We surveyed the 24 active, local land trusts in North Carolina (U.S.A.) to determine how they report progress toward attaining such conservation goals. Twenty-two land trusts responded to our survey. Of these, eight reported developing specific conservation goals for all of the properties they protect, five identified conservation targets on all properties, and two reported monitoring biological indicators on all of their protected properties. On the basis of these results, we believe most of the land trusts surveyed could not determine whether they were meeting conservation goals because most did not identify explicit, measurable goals and monitor progress toward them. Instead they reported success in terms of the amount of land protected and money raised. We think this is a lost opportunity for land trusts to build sound approaches to environmental management, engage the public, entice new donors, and attain funding for additional conservation activities. We propose conservation professionals help local land trusts adopt the Open Standards for the Practice of Conservation, a framework developed by a consortium of international conservation organizations, to develop conservation goals and measure whether the goals are achieved.


Subject(s)
Conservation of Natural Resources , Goals , North Carolina
17.
J Chem Phys ; 134(11): 114702, 2011 Mar 21.
Article in English | MEDLINE | ID: mdl-21428651

ABSTRACT

We report a study of the adsorption of CF(4) on graphite preplated with a monolayer of CF(3)Cl, using infrared reflection absorption spectroscopy combined with ellipsometry. The saturated vapor pressure of CF(3)Cl is nearly 3 orders of magnitude smaller than that of CF(4) at the same temperature, so the main control variables are the temperature and the pressure (or chemical potential) of CF(4), together with the initial coverage of CF(3)Cl. The temperature range covered is 60-105 K. We find that, if the initial monolayer of CF(3)Cl is liquid, CF(4) continuously displaces CF(3)Cl by substitution in the monolayer. If the initial monolayer of CF(3)Cl is solid, due to either lower temperature or compression, CF(4) condenses as a second layer on the top of the CF(3)Cl layer, with only slight mixing with the original layer. This behavior persists to multiple layers of CF(4).

18.
Future Med Chem ; 3(2): 243-50, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21428818

ABSTRACT

We discuss the potential use of multicomponent reactions in developing small-molecule probes of GABA(A) receptor function. Two examples that illustrate this approach are presented: the synthesis of a class of compounds that specifically modulate the function of GABA(A) receptors containing the δ-subunit, and also 'caged' GABA derivatives. A caged GABA is a photolabile precursor of GABA that releases GABA upon photolysis.


Subject(s)
Receptors, GABA-A/metabolism , gamma-Aminobutyric Acid/chemistry , gamma-Aminobutyric Acid/metabolism , HEK293 Cells , Humans , Molecular Structure , Photochemistry/methods , Photolysis , Pyrimidinones/chemical synthesis , Pyrimidinones/chemistry , Receptors, GABA-A/chemistry
19.
Biochemistry ; 49(36): 7892-901, 2010 Sep 14.
Article in English | MEDLINE | ID: mdl-20726514

ABSTRACT

The malfunction of a mutated GABA(A) receptor (alpha1beta2gamma2L(K289M)) in an inheritable form of epilepsy (GEFS+, generalized epilepsy with febrile seizures plus) in humans [Baulac, S., Huberfeld, G., Gourfinkel-An, I., Mitropoulou, G., Beranger, A., Prud'homme, J. F., Baulac, M., Brice, A., Bruzzone, R., and LeGuern, E. (2001) Nat. Genet. 28, 46-48] has been accounted for by a 5-fold decrease in the channel-opening equilibrium of the mutated receptor compared to the wild type [Ramakrishnan, L., and Hess, G. P. (2004) Biochemistry 43, 7534-7540]. Here we describe the mechanism by which the neurosteroid 3alpha, 21-dihydroxy-5alpha-pregnan-20-one (5alpha-THDOC) alleviates this malfunction of the mutated receptor transiently expressed in HEK293 cells. Two rapid reaction techniques, the cell-flow and the laser-pulse photolysis methods, were used in combination with whole-cell current recordings. 150-muM 5alpha-THDOC does not affect the rate constant for channel opening (k(op)) of approximately 250 s(-1) but does decrease the rate constant for channel closing (k(cl)) from 121 +/- 11 s(-1) to 56 +/- 21 s(-1). This results in an increase in the channel-opening equilibrium constant ((Phi(-1) = k(op)/k(cl)) by a factor of about 2, leading to about 50% alleviation of the malfunction of the inheritable mutated (alpha1beta2gamma2L(K289M)) GABA(A) receptor linked to GEFS+.


Subject(s)
Desoxycorticosterone/analogs & derivatives , Epilepsy/genetics , Mutation , Receptors, GABA-A/genetics , Receptors, GABA-A/metabolism , Cells, Cultured , Desoxycorticosterone/chemistry , Desoxycorticosterone/pharmacology , Epilepsy/metabolism , Humans , Kinetics , Neurotransmitter Agents/chemistry , Neurotransmitter Agents/pharmacology , Photolysis , Transfection
20.
Biochemistry ; 49(23): 4841-51, 2010 Jun 15.
Article in English | MEDLINE | ID: mdl-20450160

ABSTRACT

Gamma-aminobutyric acid type A receptors (GABA(A) receptors) are ligand-gated chloride channels that play a central role in signal transmission within the mammalian central nervous system. Compounds that modulate specific GABA(A) receptor subtypes containing the delta-subunit are scarce but would be valuable research tools and starting points for potential therapeutic agents. Here we report a class of dihydropyrimidinone (DHPM) heterocycles that preferentially potentiate peak currents of recombinant GABA(A) receptor subtypes containing the delta-subunit expressed in HEK293T cells. Using the three-component Biginelli reaction, 13 DHPMs with structural features similar to those of the barbiturate phenobarbital were synthesized; one DHPM used (monastrol) is commercially available. An up to approximately 3-fold increase in the current from recombinant alpha1beta2delta receptors was observed with the DHPM compound JM-II-43A or monastrol when co-applied with saturating GABA concentrations, similar to the current potentiation observed with the nonselective potentiating compounds phenobarbital and tracazolate. No agonist activity was observed for the DHPMs at the concentrations tested. A kinetic model was used in conjunction with dose-dependent measurements to calculate apparent dissociation constant values for JM-II-43A (400 muM) and monastrol (200 microM) at saturating GABA concentrations. We examined recombinant receptors composed of combinations of subunits alpha1, alpha4, alpha5, alpha6, beta2, beta3, gamma2L, and delta with JM-II-43A to demonstrate the preference for potentiation of delta-subunit-containing receptors. Lastly, reduced currents from receptors containing the mutated delta(E177A) subunit, described by Dibbens et al. [(2004) Hum. Mol. Genet. 13, 1315-1319] as a heritable susceptibility allele for generalized epilepsy with febrile seizures plus, are also potentiated by these DHPMs.


Subject(s)
Epilepsy/genetics , Epilepsy/metabolism , Genetic Variation , Protein Subunits/metabolism , Pyrimidinones/pharmacology , Receptors, GABA-A/genetics , Receptors, GABA-A/metabolism , Alanine/genetics , Allosteric Regulation/genetics , Cell Line , Drug Synergism , Glutamic Acid/genetics , Humans , Mutagenesis, Site-Directed , Protein Binding/drug effects , Protein Isoforms/genetics , Protein Isoforms/metabolism , Pyrimidines/pharmacology , Thiones/pharmacology
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