The present study examined the effects of NIH 11082 ((−)-(1R,5R,9R)-5,9-dimethyl-2'-hydroxy-2-(6-hydroxyhexyl)-6,7-benzomorphan hydrochloride), a benzomorphan analogue, in the mouse tail suspension, an assay used to detect antidepressant agents. NIH 11082 significantly decreased immobility time during tail suspension, with a comparable magnitude as the tricyclic antidepressant desipramine. Importantly, NIH 11082 failed to elicit convulsions or other overt behavioral signs of toxicity. The delta-opioid receptor antagonist naltrindole (AD 50 =2.0 mg/kg), but not the nonselective mu-opioid receptor antagonist naltrexone or the kappa-opioid receptor antagonist nor-BNI, blocked the effects of NIH 11082 in the tail suspension test. These results reinforce the notion that delta opioid receptor agonists can produce significant effects in a behavioral model used to screen antidepressant drugs.

<p>Lake Lungo and Lake Ripasottile are two shallow (4-5 m) lakes located in the Rieti Basin, central Italy, that have been described previously as surface outcroppings of the groundwater table. In this work, the two lakes as well as springs and rivers that represent their potential source waters are characterized physio-chemically and isotopically, using a combination of environmental tracers. Temperature and pH were measured and water samples were analyzed for alkalinity, major ion concentration, and stable isotope (δ²H, δ¹⁸O, δ¹³C of dissolved inorganic carbon, and δ³⁴S and δ¹⁸O of sulfate) composition.  Chemical data were also investigated in terms of local meteorological data (air temperature, precipitation) to determine the sensitivity of lake parameters to changes in the surrounding environment. Groundwater represented by samples taken from Santa Susanna Spring was shown to be distinct with SO₄^2-and Mg²⁺content of 270 and 29 mg/L, respectively, and heavy sulfate isotopic composition (δ³⁴S=15.2 ‰ and δ¹⁸O=10‰). Outflow from the Santa Susanna Spring enters Lake Ripasottile <em>via</em> a canal and both spring and lake water exhibits the same chemical distinctions and comparatively low seasonal variability. Major ion concentrations in Lake Lungo are similar to the Vicenna Riara Spring and are interpreted to represent the groundwater locally recharged within the plain. The δ¹³C_DIC exhibit the same groupings as the other chemical parameters, providing supporting evidence of the source relationships. Lake Lungo exhibited exceptional ranges of δ¹³C_DIC(±5 ‰) and δ²H, δ¹⁸O (±5 ‰ and ±7 ‰, respectively), attributed to sensitivity to seasonal changes. The hydrochemistry results, particularly major ion data, highlight how the two lakes, though geographically and morphologically similar, represent distinct hydrochemical facies. These data also show a different response in each lake to temperature and precipitation patterns in the basin that may be attributed to lake water retention time. The sensitivity of each lake to meteorological patterns can be used to understand the potential effects from long-term climate variability.</p>